Preface
Last year, experts from CO2
Sciences, Columbia University
and Valence Strategic came
together to develop a roadmap.
That document, Carbon Dioxide Utilization ICEF
Roadmap 1.0, released at the UNFCCC Marrakesh
Climate Change Conference in 2016, surveyed
the commercial and technical landscape of CO2
conversion and use. The document provided
extensive background and analysis and hashelped to provide a foundation for additional
studies, including this one.
This roadmap is meant to complement andexpand upon the work of its predecessor. Basedin part on a workshop at Columbia University’s
Center on Global Energy Policy in July 2017, it
explores three distinct categories of CO2-based
products, the technologies that can be harnessedto convert CO2 to these products, and theassociated research and development needs.
It also explores the complicated topic of life
cycle analysis—critically important when
considering the climate impacts of CO2
conversion and use—as well as policy tools that
could be used to promote CO2-based products.
The authors of this new roadmap hope that it
will prompt others to explore these topics aswell, and to increase the rigor and robustnessof both life cycle analyses and techno-economic
assessments. The CO2-derived product markets
will only benefit from more scrutiny andadditional analytic work, and we invite others
to join us in cultivating an open, transparent
and actionable set of results that can undergird
future standards and business transactions in
CO2 conversion and use.

ii

Authors:
David Sandalow
Center on Global Energy Policy,
Columbia University
Chair, ICEF Innovation Roadmap
Project
Roger Aines
Lawrence Livermore National
Laboratory
Julio Friedmann
Lawrence Livermore National
Laboratory
Colin McCormick
Valence Strategic
Sean McCoy
Lawrence Livermore National
Laboratory
This roadmap was prepared tofacilitate dialogue at the FourthInnovation for Cool Earth Forum(Tokyo October 2017),
for final release at COP-23(Bonn November 2017).

November 2017

Contents
1
1 Chapter
Introduction and Overview
2
7 Chapter
Concrete and Carbonate Materials
3
17 Chapter
Commodity Chemicals
429 Chapter
Durable Carbon Materials
537 Chapter
Life Cycle Assessment
645 Chapter
General R&D Needs for CO Utilization
2

7
49 Chapter
Policy Options
8
55 Chapter
Findings and Recommendations

November 2017iii

Chapter 1:

Introduction andOverview
The Paris Agreement helped mobilize the global
community behind the goal of limiting the increase inglobal average temperatures to less than 2°C above
pre-industrial levels. Many studies have concluded
that this can be achieved with conventional mitigation
measures,1 including a significant contribution fromcarbon capture and storage (CCS).2 Other studies haveconcluded that the Paris Agreement goals require
going beyond traditional mitigation approaches andmust include removal of carbon dioxide (CO2) fromthe air and oceans, as well as geological storage orconversion to minerals.3
As with other technologies, including clean energy
technologies,4 broad deployment of CCS would
reduce costs, improve performance, and earn publicconfidence.5 Following the ratification of the Paris
Agreement, there has been increased attention on CO2
utilization (CO2U), which is the utilization of CO2 for an
economically beneficial purpose. Traditionally, CO2U
has primarily included enhanced oil recovery and theco-production of water; both of these applications
use large volumes of CO2 and result in its geologicalstorage. However, interest in CO2U has increasingly
become focused on the conversion of CO2 into otherproducts, such as cement, synthetic fuels and plastics.
Many see CO2U as a way to offset the cost of CO2
capture, which is the costliest part of the CCS chain.
Others note that it may improve public perception ofand acceptance of CCS. Both of these would be theresult of revenues and economic benefits from thecaptured CO2 that are absent from CCS today. The
combination of CO2U with CO2 removal from the airand oceans could also produce durable materials
and fuels that are not based on fossil carbon andencourage a “circular economy”.6 Finally, it is worth
noting that political opinion about CO2U is often lesscontentious than the combination of CO2 capture withgeologic storage because of potential revenues andother economic benefits.

November 2017

The growth of interest in CO2U over the last two
years has been due in part to the clarity that the Paris
Agreement provides regarding a carbon budget andthe relatively short time available to meet stabilization
goals. In addition, the recent rapid reduction of costs
for many renewable sources (notably solar and wind)
has made low-cost, near-zero-carbon electricity
abundant in both volume and geography. In somemarkets this has led to electricity being available atvery low or even negative prices,7 and even curtailmentof renewable generation at times.8 Since renewableelectricity is increasingly cheap, interest has grown
dramatically in potential applications—such as CO2U—
that can harness this abundance in an economicallyand environmentally beneficial way.
The landscape of CO2U is complex and diverse. It
involves a wide array of applications (e.g. adding
CO2 to greenhouses, conversion to liquid fuels),
technologies (e.g. electrochemical conversion using
fuel cells, thermal catalysis), energy requirements (i.e.
exothermic vs. highly endothermic), and settings (i.e.
large industrial sites vs. distributed applications). Since
the field of study is relatively young and immature,
there is only a limited amount of existing analysis
regarding potential markets for products, climate
benefits, additional benefits, and the volumes of CO2
used or potentially to be used.
It appears that there is enough potential andopportunity to expand commitment of resources into
CO2U. It also appears that planning and investment
decisions remain hampered by a lack of information,
the dynamic nature of the technology and the markets,and the changing policy landscape. Because of this,it will be important to continually revise and update
roadmap studies like this one.

1

What is CO2 utilization?
As it sounds, CO2U is the use of CO2 to produce orgenerate economically valuable products or services.
The potential range of applications is very large andincludes greenhouses, organic farming, conversion
of CO2 to fuels or chemicals, conversion to long-lived
solids (e.g. plastics, carbon fiber, graphene), andconversion to carbonate minerals.

CO2 -EOR
CO2-based enhanced oil recovery (CO2-EOR) is by far
the most well-understood form of CO2U. There is awell-established body of practice, commerce and law
around CO2-EOR, and the technology is mature. Today,roughly 17 million tons/year of anthropogenic CO2 areused for EOR.9 While there remains debate over theuse of CO2-EOR as a climate mitigation option, various
analyses have shown that it could be beneficial and it
is represented in economic and analytical models.10
Many governments, companies and investors see CO2EOR as a critical path for early CCS adoption since it
provides revenues, tax receipts, jobs and large-volume
offtakes.11 For these reasons, CO2-EOR will not be
considered further in this report.

Non-EOR applications
Because the non-EOR applications for CO₂ conversion
are so varied, the technology is also diverse. In
addition, many CO2 conversion technologies are
relatively early in their development, so a plethora ofoptions and pathways exist today that may become
technically or commercially viable in the future. The
Carbon Dioxide Utilization Roadmap 1.0 reviewed andfeatured many of the most important CO2U pathways
and markets.12 These include:■■ Minerals: CO2 can react with a range of minerals toform carbonate minerals, like calcite or magnesite.
Their uses include pharmaceutical feedstocks andbuilding materials like aggregate.
■■ Concrete: In some cases, CO2 becomes a new or
substitute feedstock in the concrete production
process; in other cases, CO2 is used to cure orprocess cement.
■■ Fuels: With added energy, CO2 can be converted to
any carbon-based fuel, including diesel, jet fuels,ethanol and natural gas.

2■■ Chemicals: Similarly, with added energy, CO2 canbe converted to a wide range of organic chemicals,
including methanol, ethylene, carbamates andothers. These may be used directly, or as feedstocks
for production of other products (e.g. plastics).
■■ Polymers: It is possible to polymerize CO2 to form
plastics and resins directly.
■■ Carbon fibers and composites: Either directly or
indirectly via CO2-based chemical intermediaries,
one can form carbon fibers, carbon composites, andother long-lived materials (like graphene).
These products all have different price points, market
volumes and performance requirements. They arealso used in different ways, have different lifetimes
and are disposed of differently, making evaluation of
their emissions impact complicated. Many of theseapplications will have specific geographic regions ofearly production or adoption based on local conditions
and resources.
It is important to note that this report doesn’t
consider CO2 conversion pathways that depend on
photosynthesis by living organisms (e.g. plants, algae).
In part, this is because such biomass-based pathways
are used widely today (e.g. bioethanol from corn andsugarcane) and continue to be the focus of researchand development, which means that there is a wealthof prior and current work to frame considerations.13
Roadmaps and similar strategic plans also already exist
for bioenergy.14 In contrast, direct CO2 conversion via
non-biomass routes is less well explored, less mature,and lacks a comprehensive review of the opportunities
and challenges.

Recent assessments and analysis
As mentioned above, recent and rapid growth ininterest around CO2U has prompted efforts to
support investments in both R&D and deployment
into markets. For example, CO2U is a specific topic
mentioned under Mission Innovation, and is partof the set of grand challenges taken up within themultinational framework.15 The Oil and Gas Climate
Initiative recently announced a dedicated annual R&D
fund, a portion of which is focused on CO2U.16 The
European Commission has begun a new effort underthe Horizon 2020 umbrella,17 and is providing funding
to a set of institutions to develop assessments for
CO2U.
November 2017

Similarly, following a review of these and other studies,
as well as the work in the first ICEF roadmap, several
uncertainties and knowledge gaps appear prominent:■■ Costs: Even for a relatively restricted class of CO2

conversion approaches (e.g. CO2 mineralizationand conversion to aggregate), little is known about
the current or likely costs, including first-of-a-kind(FOAK) or Nth-of-a-kind (NOAK). Cost uncertainties
flow from the wide range of technical approaches,a paucity of published literature and confidentiality
among companies.
■■ Market potential: The sizes of the individual
markets for specific CO2U applications vary widely.
Moreover, there is no clear sense within a given
market of the ability to compete on price or displace
incumbents, in part because non-cost factors suchas performance and standards affect analysis andcomparisons.
■■ Climate benefit: The size of the market and rate ofmarket penetration certainly affects the potential
climate benefit of a CO2U technology. So do thespecifics of a technical approach (for example, howmuch carbon is used to make a pound of plastic),
the source of the CO2, the energy needed to convert
it, and many other factors. Ultimately, these factors
must be considered in an integrated fashion, using
life cycle analysis (LCA).
■■ Potential for disruption: Some markets today arevery small, e.g. carbon fiber. However, if carbon fiber
can be made cheaply using CO2 as a feedstock, it
could potentially replace many other materials in
the market (e.g. rolled steel or aluminum), greatly
increasing the market size.
■■ Policy: Many countries, states, cities, and evencompanies are considering policy shifts in CO2U.
The range of policies under consideration today iswide, including tax credits, reporting requirements,
procurement mandates, market mandates (such asa portfolio standard) and shareholder actions. Policy
shifts could affect all the other uncertainties.
This report is an attempt to provide some clarity to thisdynamic technology and market landscape.

Focus on case studies and LCA
Making sense of the current landscape of CO2U
opportunities, technologies and markets remains
difficult. The enormous range of potential uses,
November 2017

product prices, conversion costs, and technology
options—on a dynamic landscape of technology
and policy development—complicates manystraightforward approaches to comparative analysis,
quantitative or qualitative.
Case-study methodology represents complexity welland provides a way to achieve depth of investigation.
This report focuses on a set of case studies, eachreflective of a different set of technologies andmarkets, in an attempt to represent a range oftechnologies, market conditions, and potential
outcomes. These are:■■ Concrete and carbonate materials: This case looks

at CO2U pathways with large market potential andhelpful thermodynamics (little energy is needed
to make these products). The market value of the
products is relatively low. Given technical and market
readiness, this represents an opportunity for nearterm deployment (3-10 years).
■■ Commodity chemicals: This case looks at CO2U
pathways with modest markets and CO2 volumes. In
some cases, the technology is fairly mature; less soin others. In most cases, substantial energy inputs
are required. However, the value of some of theseintermediates is quite high. These chemicals are
anticipated as feedstocks for long-lived products (e.g.
polymers). Given technical and market readiness,this represents an opportunity for near- to mediumterm deployment (5-20 years).
■■ Durable carbon materials: This case looks at CO2U
pathways that today represent relatively small
markets (e.g. carbon composites or graphene). Manyof the conversion technologies for direct singleor multi-stage conversion of CO2 are nascent andvery early in development. However, the market
potential of these materials may be quite large,
and the market value of these products ranges
from moderate to very high. Given technology andmarket readiness, this represents a long-term set ofopportunities.
Estimating the climate benefits for these different
approaches and products is difficult. Differentiatedand specific information inputs are needed to executean accurate life cycle analysis (LCA) for any specificproduction pathway, and the scope, boundaries, anddetailed methodological assumptions of LCA havea significant impact on the result. Since a critical3market and environmental value of CO2U is thenet carbon reduction, this report features a review
and discussion of both the current state of the art
and the key challenges in undertaking precise andaccurate estimation of CO2U LCA. An important
conclusion is the need for guidelines and standards
for accounting CO2U carbon balances. Standards(such as those established by the International
Organization for Standardization) will help facilitate
market adoption, as well as undergird policy decisions
and the development of regulations. However, given
the intrinsic complexity and early stage of CO2U
technologies and markets, it may prove challenging toachieve precision and accuracy for LCA of early-stage
pathways, and guidance may need to be adapted
over time to address the lessons from such analyses.
A further point to emphasize is that LCA should beincorporated in the technology development processfrom an early stage, for example, though “hotspot”
and improvement analyses. As the technology
matures, these studies should be progressively
refined, providing both guidance for future research
directions and an increasingly useful assessment of atechnology’s climate impact.
1

2

3

4

Otmar Edenhofer et al., eds., Climate Change 2014:
Mitigation of Climate Change. Contribution ofWorking Group III to the Fifth Assessment Reportof the Intergovernmental Panel on Climate Change(Cambridge, United Kingdom and New York, NY, USA:
Cambridge University Press, 2014).
IEA, Energy Technology Perspectives 2015: Mobilizing
Innovation to Accelerate Climate Action (Paris, France:
International Energy Agency, 2015); Elmar Kriegler
et al., “The Role of Technology for Achieving Climate
Policy Objectives: Overview of the EMF 27 Study on
Global Technology and Climate Policy Strategies,”
Climatic Change 123, no. 3–4 (April 1, 2014): 353–67,
doi:10.1007/s10584-013-0953-7; Detlef P. van Vuuren
et al., “The Role of Negative CO2 Emissions for
Reaching 2 °C—insights from Integrated Assessment
Modelling,” Climatic Change 118, no. 1 (2013): 15–27,
doi:10.1007/s10584-012-0680-5.
UNEP, “The Emissions Gap Report 2016” (Nairobi,
Kenya: United Nations Environment Programme,
2016), http://wedocs.unep.org/bitstream/
handle/20.500.11822/10016/emission_gap_

report_2016.pdf; Benjamin M. Sanderson, Brian C.
O’Neill, and Claudia Tebaldi, “What Would It Take toAchieve the Paris Temperature Targets?,” GeophysicalResearch Letters 43, no. 13 (July 16, 2016): 7133–42,
doi:10.1002/2016GL069563; Pete Smith et al.,“Biophysical and Economic Limits to Negative CO2Emissions,” Nature Climate Change 6, no. 1 (January2016): 42– 50, doi:10.1038/nclimate2870.
4

Timothy J. Foxon, “Stimulating Investment in Energy
Materials and Technologies to Combat Climate
Change: An Overview of Learning Curve Analysis andNiche Market Support,” Philosophical Transactionsof the Royal Society A: Mathematical, Physical andEngineering Sciences 368, no. 1923 (2010): 3469–83,
doi:10.1098/rsta.2010.0106.

5

IEA, Energy Technology Perspectives 2015.

6

F. S. Zeman and D. W. Keith, “Carbon Neutral
Hydrocarbons,” Philosophical Transactions of the Royal
Society a- Mathematical Physical and Engineering
Sciences 366, no. 1882 (November 2008): 3901–18,
doi:10.1098/rsta.2008.0143.

7

A. Hove and K. Mo, 2016, Going for Gold: Championing
Renewable Integration in Jing-Jin-Ji, Best practices
from Germany and Texas, Paulson Institute, http://
www.paulsoninstitute.org/economics-environment/
climatesustainable- urbanization/research/going-forgold-championing-renewable-integration-in-jing-jin-ji/

8

CAISO. Wind Solar Real-time Dispatch Curtailment
Report Oct 04 2016, page 4/5

9NEORI, “Carbon Dioxide Enhanced Oil Recovery: A
Critical Domestic Energy, Economic, and Environmental
Opportunity” (Washington, DC: National Enhanced Oil
Recovery Initiative, 2012).

10

IEA, “Storing CO2 through Enhanced Oil Recovery”(Paris, France: International Energy Agency,2015), https://www.iea.org/publications/insights/
insightpublications/storing-co2-through-enhanced-oilrecovery.html.

11

National Coal Council, “CO2 Building Blocks: Assessing
CO2 Utilization Options” (Washington, D.C.: National
Coal Council, 2016), http://www.nationalcoalcouncil.
org/studies/2016/NCC-CO2-Building-Block-FINALReport.pdf; Stefan Bachu et al., “Technical Challenges
in the Conversion of CO2-EOR Projects to CO2 Storage
Projects” (Washington, DC: Carbon Sequestration
Leadership Forum (CLSF), 2013).
November 2017

12

13

14

Issam Dairanieh et al., “Carbon Dioxide Utilization(CO2U) – ICEF Roadmap 1.0” (Tokyo, Japan: ICEF
Innovation Roadmap Project, 2016), http://www.
icef-forum.org/platform/upload/CO2U_Roadmap_
ICEF2016.pdf.
Felix Creutzig et al., “Bioenergy and Climate Change
Mitigation: An Assessment,” GCB Bioenergy 7,
no. 5 (September 1, 2015): 916–44, doi:10.1111/
gcbb.12205.
IEA, “Technology Roadmap: Biofuels for Transport”(Paris, France: International Energy Agency, April
20, 2011), https://www.iea.org/publications/
freepublications/publication/technology-roadmapbiofuels-for-transport.html; IEA, “Technology Roadmap:
Bioenergy for Heat and Power” (Paris, France:
International Energy Agency, May 29, 2012), https://www.iea.org/publications/freepublications/publication/

November 2017

technology-roadmap-bioenergy-for-heatand- power-.
html.
15

Mission Innovation, “Carbon Capture Innovation
Challenge – Mission Innovation,” Mission Innovation,accessed September 11, 2017, http://missioninnovation.net/our-work/innovation-challenges/
carbon-capture-challenge/.

16

OGCI, “OGCI Climate Investments,” Oil and Gas Climate
Initiative, accessed September 11, 2017, http://www.
oilandgasclimateinitiative.com/climateInvestments.
html.

17

European Commission, 2016, Research and Innovation
Participant Portal, Horizon 2020 Prize for CO2 Reuse,
http://ec.europa.eu/research/participants/portal/
desktop/en/opportunities/h2020/topics/lce-prizeco2reuse-01-2016.html

5Chapter 2:

Concrete andCarbonate Materials
Introduction
The largest near-term opportunity for utilizing CO2
is in cement and the aggregates used in concretematerials.1 This is because of the extraordinary
volume of these materials used commercially, theirpermanence, and the favorable chemistry involved.
For these reasons, this chapter will consider CO2U
for cement and aggregates as a near-to-market casestudy, illustrating how policy can support the further
development and deployment of this technology.
Cement, along with aggregate and water, are themain components of concrete (see Box 2.1). The 2016
market for concrete was around 30 billion tons (Gt) of
product, based on the global cement market size of
approximately 4 Gt.2 The Carbon Dioxide Utilization
Roadmap 1.0 estimated that the total market for
concrete would grow to about 40 Gt in 2030.3 It
further estimated that the worldwide aggregatesmarket was between 25 Gt and 35 Gt in 2015, andwould grow to about 50 Gt of product in 2030.
There are several approaches to incorporating CO2 into
concrete. In direct utilization systems, the amount of
CO2 consumed varies between 0.15%4 and 24%5 by
weight of traditional Portland cement used, or 0.02%
to 3% by weight of concrete. Applying direct utilization
systems to all concrete produced in 2016 would, thus,
create a demand between 10 MtCO2 and 1000 MtCO2

globally, and up to 1200 MtCO2 in 2030. Aggregates
could consume on the order of several billion
additional tons of CO2 if they were partially madefrom CO2.6
These large market volumes make concrete andaggregates an attractive target for CO2U. In addition,these products result in an effectively permanentmeans of sequestering CO2: mineral fixation. Thismeans that they have a clear leg up relative to other
CO2-based products in terms of climate impact.
Additionally, this application takes advantage of two
important characteristics of CO2:
1. CO2 is a very low-energy molecule, meaning thatconverting it to most other relevant molecules(such as liquid fuels) requires adding significant
amounts of energy (refer to Section 3). However,the form of carbon that makes up cements andaggregates (carbonate, CO32-) is an even lowerenergy molecule. If the conditions are properly
established, CO2 can be chemically converted into
carbonate without the need for external energy todrive the reaction. This is extremely important formaking large volumes of material, which could beprohibitively expensive and emissions-intense if
there were a need to add energy to the reaction.
2. The second characteristic is seemingly pedestrian
but important: CO2 weighs a lot. This is anunder-appreciated requirement for many uses ofconcrete, where the sheer mass of material is an
important building element (see Figure 2.1).
These characteristics have led to several proposed usesof CO2 as part of the actual binding material (cement),
and as a component of the filler (aggregate) thatmakes up most of concrete by mass. Both cement andFigure 2.1. The concrete pylons of the San Francisco Bay Bridge counter the weight of the suspension bridge andvehicles by simply being heavier. https://www.pexels.com.
November 2017

7

BOX 2.1 Cement and Concrete

Concrete that is used in the construction industry is a mixture of cement (sometimes referred to as binder),water, and solid aggregates such as sand, gravel, and crushed stone (sometimes referred to as filler). A typical
mixture by volume is 10-15% cement, 15-20% water and 60-75% aggregate. Manufacturing cement involves
heating limestone (calcium carbonate) and clay materials (primarily alumino-silicates) in a kiln to form amaterial known as clinker, which is then ground into a fine powder. When this is mixed withwater and aggregates, a series of chemical processes (“curing”) converts the cement
powder into interlocking crystals, which grow stronger over time. These crystals
give concrete very good compression strength—so it can support a lot ofweight—but poor tension strength, meaning that it cannot resist being
pulled apart unless other materials are added, such as steel (“rebar”).
Since the hydrated calcium oxide found in cement is very reactive with
CO2—in fact, CO2 is naturally taken up by the cement over time—it ispossible to return some of that CO2 to the product.
aggregate applications require the carbonate ion to bebalanced by a cation with two positive charges: mostoften calcium (Ca++) or magnesium (Mg++). Both cationcarbonate ion pairs are also very common minerals innature: calcium carbonate is limestone or marble, andmagnesium carbonate, while less common, is a natural
material called magnesite with comparable properties
to limestone.

and markets are also nearby. Slags and other alkaline
industrial wastes also contain the appropriate ions,and at scales of a few hundred million tons, may be
extremely valuable feedstocks to make carbonate
solids. Use of industrial wastes may also be viewed asa means of waste treatment, resulting in stabilizationof metals that might otherwise be hazardous in theenvironment.8

The requirement that cations balance the charge
on the carbonate ion CO32- is the most important
challenge to making carbonates and cements. Divalentions (+2 charged) are strongly preferred; unfortunately,
they are not broadly available. The largest commercial
source of +2 calcium is limestone, but extracting thecalcium cations from this rock releases carbon dioxide,making it impossible to achieve any net climate
benefit. Monovalent ions like sodium and potassium(Na+ and K+) can also balance the charge and be
obtained at much lower cost and emissions footprint.
However, using them as cations usually results inwater-soluble solid products of limited commercial use
as construction materials.

The use of these compounds as building materials
dates back thousands of years, and there is
widespread experience with their performance in suchapplications, including their non-toxic and long-lasting
natures. Meeting expectations (and standards)
for their performance–particularly tensile andcompressive strength metrics–is the most important
aspect of making new materials containing CO2 (seeBox 2.2). Understanding the impact of CO2 addition
to the products and gaining widespread acceptanceof the practice is, thus, critical. On the other hand, it
is widely accepted that the nature of the materials
and their use means that carbon fixed in cements andaggregates is likely to remain in this form indefinitely,
keeping it out of the atmosphere for hundreds or eventhousands of years.

One possible alternative source of calcium andmagnesium is seawater, which is a very large resource.
This is an active area of research.7 Another possible
source is ultramafic rocks or (in lower concentrations)basaltic lava. Transporting these heavy rocks to a sitewhere they could be reacted with CO2 is the primaryeconomic impediment of this approach, but could beovercome in strategic locations where CO2 sources

8

State of the technology
More than 20 organizations are actively engaged incommercializing processes to convert CO2 to carbonate
products for the construction sector (Figure 2.2).
CO2-based aggregates, concrete, and pre-cast concrete

November 2017

Feedstock

1

3

5

7

9

Brine,
SeawaterMinerals

Alkaline
WastesCO2
DirectUtilization

Figure 2.2. Stages of technology development for concrete and carbonate materials. (credit: Sean Zhou, Columbia
University)
products are commercially available today. The primarydifference among the technology pathways is thesource of the cation to pair with the carbonate ion.
■■ Pathways using calcium from seawater are primarily

using electrochemical means to separate the calcium
from seawater, although if done improperly thisapproach can release CO2 from seawater as well andnegate the climate benefit.
■■ Mineral sources are inherently easier to use, but
require transport of either rock to the carbonation
site, or carbonate product to the construction site.
In some cases, they also require additional capitaland energy for grinding and processing mineral
feedstocks.
■■ Approaches using alkaline wastes are the mostadvanced category because the calcium andmagnesium ions in wastes like iron slag areconcentrated (up to 40% by weight) and are moreclimate-friendly to use, since their utilization only
releases oxygen as the cations are changed fromoxygen-compensated (CaO, MgO) to carbonate(CaCO3, MgCO3).
■■ A final category follows a slightly different approach:instead of attempting to make a carbonate product,some organizations are replacing water in cement
November 2017with carbon dioxide. Two companies, CarbonCureand Solidia Technologies, currently sell commercial
products in this space.

Technical and economic limitations
Although the potential markets are large andmuch of the fundamental chemistry and physics iswell-understood, all approaches face some sort oftechnical challenge for economic viability. Some ofthese issues involve pre-processing of feedstocks,
including transportation and size reduction (crushing)costs. Other issues involve adding energy or new
chemical pathways to accelerate key reactions, butwith additional capital or operating expense. These
challenges all appear surmountable, either throughimproving technical aspects of the work (e.g. higher
efficiency, lower equipment cost) or improving the
economics of the process or products. The companies
involved are working to overcome these obstacles.
Seawater-Sourced Calcium. This approach benefits
from a nearly unlimited source of calcium fromseawater, which is routinely available near large
industrial sources of CO2. An related option is to obtaincalcium from brines found deep in sedimentary basins(where oil reservoirs are also found), many of which
originally came from seawater. These sources have9

calcium ions compensated by chloride ions. If thecalcium ions are to be used elsewhere, the chloride
ions must either be converted to neutral chlorine gas,a useful industrial product, or be compensated bysome other ion by an ‘ion exchange’ process.
Calera Corporation demonstrated considerable
progress in this area, ultimately developing an
advanced electrolysis system for extracting calcium
and chlorine, that proved economic on the basis of thesale of the chlorine product.9 An innovative aspect of
this process was the use of the calcium carbonate as asupplemental cementing material by encouraging thecreation of interlocking crystals that provide valuable
tensile strength. Calera has demonstrated productionof a fiber cement board from this process.10 However,
although there is a nearly unlimited source of calcium,the profitability of this process depends on the sale ofchlorine gas, which has a market of about 60 million
tons per year,11 much smaller than the potential
cement and aggregate market.
Technology development pathways in this area focus
on reducing energy expense. They include more
efficient electrolysis methods and innovative ionexchange processes. Additional research on converting
byproduct wastes into valuable products would also
improve the economics.
Mineral-Based Calcium. A large quantity of available
calcium appropriate for carbonation exists in thestockpiles of asbestos-, nickel- and diamond-mining
wastes,12 but almost no commercial work exists toturn these feedstocks into construction materials.
This is principally because of geographic mismatch. In
general, large industrial CO2 sources do not exist nearmost mines creating this kind of waste, and the costof transporting this material makes it economicallyunviable. However, these wastes carbonate readily—even without any encouragement beyond the original
grinding process used to extract the product. Thus,
one approach is to use these wastes to absorb CO2
from the atmosphere, but not immediately convert theresult into a valuable product. The DeBeers company
has announced that they will carbonate their minetailings in order to offset the CO2 emissions associatedwith diamond-mining operations.13
Basalt rock found in many volcanic regions of theworld could also be used as a source of mineral-based
calcium. One cubic kilometer of basalt contains
10

enough magnesium and calcium to capture one billion
tons of CO2. This is being investigated as a means ofsubsurface storage in the United States and Iceland,
but no schemes to harvest that calcium as a precursor
to building material have yet been announced.
This is due to the relatively lower concentration ofmagnesium and calcium in basalt (5-10%) comparedto the relatively higher concentrations in asbestos-,
nickel- and diamond-mining waste (10-50%).
Technology development pathways in this area include
the development of high-value products that could betransported long distances at a profit. Construction
materials would likely need to be decorative or
high-functioning to meet this criterion, rather thanthe bulk cements and aggregates already discussed.
Alternatively, a sufficiently high carbon price could
make aggregate sourced in mine wastes profitable,
leading to early introduction of these products into
the market.
Alkaline Industrial Waste-Sourced Calcium,
Magnesium and Iron. An extensive literature exists
in this area,14 and a number of commercial ventures
have been undertaken. Industrial wastes such as steelslag contain large amounts of calcium, magnesium andeven iron, which can also participate in carbonation
reactions. These materials are generally land-filled
and using them productively could create economic
benefits in addition to the value of the new products,
due to reduced landfill costs. Many authors include alarge variety of industrial wastes, such as fly ash fromcoal plants, in the list of potential starting materials,
but the degree of reactivity varies greatly as does theconcentration of divalent ions required to bind tothe carbonate. Worldwide sources of highly reactive
material appear to be capable of consuming CO2 on
the order of 100 million tons per year.
Most of these materials require some significant
pre-treatment to react at industrially significant
rates. Many studies have examined heat treating to“activate” these wastes, making them react with CO2
in a matter of seconds. This commonly introduces
significant cost, both in terms of capital and operating
expense. An important exception is red mud fromaluminum production, which contains iron oxide,
and reacts spontaneously with CO2 in waste ponds.
However red mud also contains other metallic oxides
which do not spontaneously react into a usable
November 2017

product, adding a cost for processing. This points out asignificant limitation in the use of industrial wastes: theyoften require significant separation before or after use.
Technology development pathways include combining
activation and separation approaches—a significant
R&D challenge. For example, activation could beenhanced through the development of new catalysts
and low-cost reactors.
Direct Utilization of CO2. The final major category
concerns producers that take a different approach—replacement of water in cements with CO2. This canoccur in two different ways: CO2 can either be added
to conventional cements during the grinding phase, or
it can be added during the final curing of the cement
by replacing some water with CO2. In addition, both
approaches result in a reduction in the amount ofclinker required in the final mixture (to achieve a
consistent strength), thus leading to reduced emissions
from the production of the cement.
CarbonCure is pursuing technology based on thisapproach that can be retrofitted to conventional“ready-mix” concrete plants.15 CO2 is injected into
the concrete mix at the plant, and as the concrete
cures, the CO2 is permanently mineralized. This takes
advantage of the fact that the primary binding phase,
calcium oxide, was created by removing CO2 fromlimestone, which can be reversed, reducing the overall
carbon footprint of the cement while still providing
the necessary new formation of minerals required
to bind the cement and aggregate together. The
resulting concrete has been measured to have better
compressive strength performance than that madewith ordinary Portland cement.16
Solidia Technologies has taken this approach one stepfurther by changing the makeup of the ‘clinker’ thatcomes out of the cement kiln.17 By using more silicarich materials, they achieve a cement mixture thatbinds with more CO2 and can be used to make highstrength pre-cast materials, as well as reducing boththe consumption of limestone and the temperature
required in clinker production. However, this cement
must be cured in a sealed environment, limiting it toprecast objects for now.
The research pathways in this case focus on processdevelopments to increase the amount of CO2 absorbed
while still maintaining a strong and competent product.
Understanding changes in performance properties
November 2017

resulting from CO2 addition is currently a major
research and development objective. Methods toapply CO2 during curing of large construction concretes
could greatly expand the applicability of CO2U, as
could easier means to more directly measure theamount of CO2 that has been taken up by concretes.
Sodium and Potassium-Compensated Materials. The
use of +1 ions to combine with carbonate results in
products that are not permanent building materials,
but rather products used as industrial chemical
feedstocks and animal supplements. Skyonic18 isdeveloping technology that takes advantage of acoupled process that simultaneously removes CO2 andother contaminants such as sulfur oxides.

Market considerations
The billions of tons of CO2U potential in cement andaggregate represent low-margin, highly standardized
markets that are difficult to penetrate with new
products.19 Successful businesses to date have focusedon making incremental changes to traditional concrete
formulation to minimize the acceptance challenges,
or on niche markets. Significant penetration into thebillion-ton global cement market will be very slow by
this method. On the other hand, use of carbonate as
aggregate does not face such significant hurdles tomarket entry, but does face significant cost pressures.
With gravel costs typically in the vicinity of $50/ton
even in high-priced markets like California, it is unlikelythat an industrial process making a CO2-based productwill be competitive purely on price. This will be truein most major construction markets absent policy
support. Regulatory considerations are critical (seeBox 2.2).
The billions of tons of potential market and carbon
mitigation also appear to require significant technology
development to be accessible. Direct CO2 utilization
as an additive in conventional products is the mosttechnologically mature approach, and if regulatory
acceptance can be achieved, this approach could
utilize several percent CO2 by weight of concrete inpre-cast applications where the “green” nature of the
product is valued. With the EU, United States, andChina all showing signs of such valuation, this market
will probably expand. Particularly in the EU, cement
manufacturers are reporting their carbon footprints
and competing to reduce them. This effort is mainly
focused on more efficient clinker production and using
11BOX 2.2 Regulations and Standards22

CO2 utilization can be pursued to create products using new methods, materials or feedstocks. In many
instances, the products will need to adhere to existing codes and standards to be accepted in the marketplace.
Often, there can be barriers within the codes and standards framework that discourage products made using
new technologies.
Codes and standards are typically overseen by members of government andindustry, and developed by consensus-based and voluntary committees.
Often, there are few incentives to update or expand existing standards.
Further, even if the willingness exists, the changes to the regulatory
framework can occur slowly. A process extending to 10 years is not unusual.
The route to acceptance under codes and standards can be long enoughto discourage the entrance of new technology into the market.
					—Sean Monkman, Carbon Cureless clinker, which has resulted in a 22% reduction
in carbon footprint for the European manufacturer
Heidelberg Cement since 1990.20 Efforts such as thiswill have a significant impact on overall emissions, andas efficiency limits are reached, these corporations
may be expected to take on new carbonation
approaches to continue their reductions. Expansionof those ambitions to the Chinese market, at nearly
2 billion tons of supply,21 would have a significant
impact on world CO2 emissions.

Life-cycle analysis considerations
Production of concrete is very emissions-intensive,
releasing approximately 240 kgCO2-eq to 320
kgCO2-eq per m3 (or approximately 104 to 139
kgCO2-eq/t cement).23 The production of clinker is
responsible for 90%–98% of cement greenhouse gas
emissions. The main contributors to emissions fromclinker manufacturing are the release of CO2 during
calcination of limestone (i.e. calcium carbonate, CaCO3)
to produce calcium oxide (CaO), and the fuel emissions
associated with heating the raw materials to over
1400 °C during sintering (i.e. formation of calcium
silicates). Reducing clinker use or changing the cement
chemistry to reduce limestone use or the maximum
temperature required—while still providing a finishedconcrete that meets or exceeds required measures of
performance—are clear means to reduce emissions.
Both industrial routes to direct CO2 utilization achieve a
lifecycle emissions benefit by reducing limestone use.24

12

Solidia may also achieve a benefit by using a cement
chemistry that requires a lower sintering temperature(approximately 1200 °C).25
In addition to the above lifecycle emissions benefits,
direct CO2 use results in the accelerated uptake of CO2
by the concrete. This is referred to as “accelerated”
because the mixed calcium hydroxide ‘gels’ thatmake up the binding phase in conventional concrete
naturally absorb CO2 from the atmosphere at very
slow rates. In a case study of the conventional cement
lifecycle in the Nordic countries—including crushingof concrete after demolition—the authors estimate
between 33% and 57% of the emissions from cement
manufacture are later absorbed by the cement.26 In a
comparable study of the United States, in which thelifecycle excludes demolition and crushing, the authors
estimate that the concrete only reabsorbs about 8% of
the manufacturing emissions.27
The potential benefits of accelerated uptake in direct
CO2 utilization are twofold: CO2 is removed more
rapidly, and more CO2 may be absorbed throughnatural carbonation than would otherwise occur. The
first benefit may be particularly important, given thatthe large emissions from cement manufacture occur
near the beginning of the lifecycle. Thus, the more
rapidly the absorption offset occurs, the greater the
climate benefit (Chapter 5 discusses accounting fortime-dependent emissions in LCA). However, to date
only one peer-reviewed estimate has been made ofthe emissions benefit of direct CO2 use in concrete,28
November 2017and this is clearly an area where additional analysis isneeded.

TECHNOLOGY

In contrast, the lifecycle of CO2-based aggregate
production has been assessed in a handful of studies.29
Collectively, these studies have considered ex-situ
mineralization of two distinct categories of alkalinity
sources: ultramafic minerals (i.e. olivine, serpentine
and wollastonite) mined for use in the process; andvarious waste streams (fly ash, cement kiln dust, andsteel slag). All but one of these studies30 have assessed
the emissions reduction potential of mineralization of
CO2 as the end goal, concluding that they result in a
net emissions reduction. The single study that lookedat the beneficial re-use of the CO2-based aggregatesconcluded that it made only a small difference to theoverall lifecycle emissions benefit because the avoided
emissions from aggregate mining are small and the
additional process steps required to prepare the CO2based aggregates for re-use offset much (or all) of thebenefit. This is a significant difference from concrete,
where reduction in use of Portland cement appears tobe the driver of emissions reduction benefit.

The aggregate studies highlight that there is a great
deal of variability between processes identified in theliterature31 and between alkalinity sources.32 In fact,
few of the processes under commercial development
have publicly available, peer-reviewed LCA results.
One of the existing studies also identifies ways tooptimize CO2-based aggregate production processes
to maximize the emissions re-absorption benefit.33
This latter finding is an excellent example of the way inwhich LCA results can be used to inform research anddevelopment (R&D).
Alternative cement formulations will not evolve on alinear path with one technology taking precedence.
Alternative clinker, more efficient production ofclinker, and supplementing conventional cement with
CO2-amended materials will move forward together.
(Figure 2.3) In addition, there are multiple otheropportunities to reduce greenhouse gas emissions
from concrete manufacturing, some of which can beapplied today (e.g. materials efficiency) and some ofwhich are longer-term objectives for the industry (e.g.
CCS).34 Given the differences between the ways in

Near-term(1-3 years)

Medium-term(2-8 years)

Long-term(4-15 years)

Fully commercialized(5-20 years)

Test methods to
add CO2 to conventional cements

Evaluate
performance andability to meetcurrent standards

Increase amountsof CO2, long-term
testing of
permanence

Full scale
production

Demonstrate atpilot scale.
Meet standards

Design full-scale
production cell

Demonstrate
production atpilot scale

Demonstrate
use in multiple
products

Encourage newminimum standards
for specific uses

Developnew cement
formulations

EMISSIONS

Develop testing
methods to verify
CO2 content andsourceUtilize verified datato confirm LCA
analyses. Update
LCA methods

Confirm LCA in
production
environments

STANDARDS

Design costeffective aggregate
creation

Demonstrateconsistent productionof high-quality
materials

Identify standards
to amend to
performance base

Adjust standards
and establish
testing protocols

Certify CO2enhanced concrete
for specific uses

Figure 2.3. Conceptual roadmap for accelerating the development and certification of CO2-enhanced concrete.
November 201713

which concrete is manufactured and used regionally,
the lowest-cost options to reduce emissions willvary. An important objective for industry bodies (e.g.
World Business Council for Sustainable Development)
and intergovernmental organizations (e.g. UNIDO,UNEP) should be the continued development ofregional roadmaps that show the opportunities toincrementally reduce their emissions while creating
value for the industry.

Recommendations/Conclusions
Cement and aggregate have a large market potential
for CO2 utilization, but that potential is in fact divided
into smaller opportunities that require separate paths
to full achievement.
Aggregate by itself appears to require direct incentives
for CO2 utilization to be economically viable. The
methods by which CO2 can be turned into industrially
useful aggregate are well-established, and the costs
always exceed the cost of conventional aggregate likegravel or even crushed stone. The “low-hanging fruit”
in this area involves avoiding the cost of industrial
waste disposal, which improves the market for cementkiln dust, iron slag, aluminum red mud and coal fly
ash. It is likely, however, that the social acceptabilityof those methods will vary widely by market, with ironslag and aluminum red mud achieving much higher
utilization because the value of the original product(iron and aluminum) is expected to stay high. R&D in
the separation of undesirable contaminants will be
crucial to achieve widespread market penetration forthese products.
Cement and concrete alternatives and carbon footprint
reductions are already being pursued to achieve“green” product distinctions. A critical need in thisarea is life cycle assessment that accurately includes
the efficiency and carbon-utilization benefits as small
proportions of CO2 are added to products. This canhave a multiplicative effect through the reduction ofother raw materials.
The second, and perhaps dominant, need in thisarea is for demonstration projects that create large
volumes of these alternative materials to aid in theregulatory evaluation and acceptance for materials
that have critical construction requirements. Some
early-market penetration can be expected in shopbuilt materials that can be tested by standard ASTM

14

methods today—this is an early-adoption pathway thatis proving successful and can be expanded. Industry
and government influencers should act to foster aregulatory environment that promotes a measured andfair process to ensure that products meet both quality
and safety requirements yet innovative technologies
can enter and compete in the marketplace without
undue resistance.
Methods to evaluate the benefits and performance ofsite-poured cements and concretes do not appear toexist, and should be encouraged.
The overall lifecycle for concrete as it ages in use is notwell understood, particularly when it is removed andreused as aggregate in new concrete, as is commonly
the case. This may be an excellent opportunity toencourage more cement carbonation, and should beresearched.
1

Issam Dairanieh et al., “Carbon Dioxide Utilization(CO2U) – ICEF Roadmap 1.0” (Tokyo, Japan: ICEF
Innovation Roadmap Project, 2016), http://www.
icef-forum.org/platform/upload/CO2U_Roadmap_
ICEF2016.pdf.

2

USGS, “MINERAL COMMODITY SUMMARIES 2016”(Reston, VA: U.S. Geological Survey, 2016), https://minerals.usgs.gov/minerals/pubs/mcs/2016/mcs2016.
pdf.

3

Growth in the CO2-based concrete curing market was
6.5 Gt, 10.5 Gt and 16.5 Gt in their scenarios. Dairanieh
et al., “Carbon Dioxide Utilization (CO2U) – ICEF
Roadmap 1.0.”

4Sean Monkman and Mark MacDonald, “OnCarbon Dioxide Utilization as a Means to Improve
the Sustainability of Ready-Mixed Concrete,”
Journal of Cleaner Production, n.d., doi:10.1016/j.
jclepro.2017.08.194.

5

Warda Ashraf, “Carbonation of Cement-BasedMaterials: Challenges and Opportunities,” Construction
and Building Materials 120 (September 1, 2016):
558–70, doi:10.1016/j.conbuildmat.2016.05.080.

6

Dairanieh et al., “Carbon Dioxide Utilization (CO2U) –ICEF Roadmap 1.0.”

7Natasha and Lalasari 2017: http://aip.scitation.org/
doi/abs/10.1063/1.4974443, PNNL/ARPA-E: https://arpa-e.energy.gov/?q=slick-sheetproject/ extractingmagnesium-seawater.
November 2017

8Peter J. Gunning et al., “Secondary Aggregate from
Waste Treated with Carbon Dioxide,” Proceedingsof the Institution of Civil Engineers - Construction
Materials 164, no. 5 (October 1, 2011): 231–39,
doi:10.1680/coma.1000011.

9

Scientific Synthesis of Calera Carbon Sequestration
and Carbonaceous By-Product Applications Consensus
Findings of the Scientific Synthesis Team January 2011
Co-Chairs Durwood Zaelke, Oran Young, & Stephen O.
Andersen Donald Bren School of Environmental Scienceand Management University of California, Santa
Barbara10

11

Carbon Mineralization by Aqueous Precipitation for
Beneficial Use of CO2 from Flue Gas Final Scientific/
Technical Report Principle Investigators Martin
Devenney Ryan Gilliam Project Director Randy Seeker
Report Date: June 2015 U.S. Department of Energy
National Energy Technology Laboratory Carbon
Capture and Sequestration from Industrial Sources
and Innovative Concepts for Beneficial CO2 Use Award:
DE-FE0002472 Reporting Period Start: January 15,
2010 Reporting Period Stop: June 30, 2015 Calera
Corporation 7697 Highway One at Dolan Road Moss
Landing, California 95039
Chlorine Market: Global Industry Analysis andOpportunity Assessment 2015-2025. Future Market
Insights. http://www.futuremarketinsights.com/
reports/chlorine-market

12Strategizing Carbon-Neutral Mines: A Case for Pilot
Projects Ian M. Power, Jenine McCutcheon, Anna
L. Harrison, Siobhan A. Wilson, Gregory M. Dipple,
Simone Kelly, Colette Southam and Gordon Southam.
Minerals 2014, 4, 399-436; doi:10.3390/min4020399

13

De Beers Pioneers Research Program to Make CarbonNeutral Mining a Reality. https://www.debeersgroup.
com/en/news/companynews/ company-news/
de-beers-pioneers-research-programme-to-makecarbon-neutral-mini.html

14

An Innovative Approach to Integrated Carbon
Mineralization and Waste Utilization: A Review
Shu-Yuan Pan, Andrew Chiang, E-E Chang, Yi- Pin
Lin, Hyunook Kim, Pen-Chi Chiang Aerosol and
Air Quality Research, 15: 1072–1091, 2015 CO2Mitigation Potential of Mineral Carbonation with
Industrial Alkalinity Sources in the United States
Abby Kirchofer, Austin Becker, Adam Brandt, andJennifer Wilcox, dx.doi.org/10.1021/es4003982 |November 2017

Environ. Sci. Technol. 2013, 47, 7548−7554 Alkaline
residues and the environment: a review of impacts,
management practices and opportunities Helena I.
Gomes, William M. Mayes, Mike Rogerson, Douglas I.
Stewart, Ian T. Burke Journal of Cleaner Production 112(2016) 3571e3582 A review of mineral carbonation
technologies to sequester CO2 A. Sanna, M. Uibu, G.
Caramanna, R. Kuusik and M. M. Maroto-Valer Chem.
Soc. Rev., 2014,43, 8049-8080
15

Sean Monkman et al., “Properties and Durabilityof Concrete Produced Using CO2 as an Accelerating
Admixture,” Cement and Concrete Composites
74 (November 1, 2016): 218–24, doi:10.1016/j.
cemconcomp.2016.10.007; “CarbonCure |Transforming the Space We Live in,” accessed
September 12, 2017, http://carboncure.com/.

16

Monkman et al., “Properties and Durability of Concrete
Produced Using CO2 as an Accelerating Admixture.”

17“Solidia Cement: Part One of a Two-Part Series
Exploring the Chemical Properties and Performance
Results of Sustainable Solidia Cement and Solidia
Concrete” (Piscataway, NJ: Solidia Technologies,
December 17, 2013), http://solidiatech.com/
wp-content/uploads/2014/02/Solidia- Cement-WhitePaper-12-17-13-FINAL.pdf; Ashraf, “Carbonation of
Cement-Based Materials.”18

http://www.carbonfreechem.com

19

Karen L. Scrivener, Vanderley M. John, and Ellis
M. Gartner, “Eco-Efficient Cements: Potential,
Economically Viable Solutions for a Low-CO2, Cementbased Materials Industry” (Paris, France: United
Nations Environment Programme, 2016).

20

https://www.worldcement.com/europe-cis/17072017/heidelbergcements-sustainability-challenge/

21

https://dealbook.nytimes.com/2014/04/07/
chinas-dominance-in-cement-has-little-effect-oneuropean-suppliers/ https://www.worldcement.com/
the-americas/17022017/us-cement-capacity-sufficientto-meet-demand/22

Box text provide by Sean Monkman, CarbonCure.

23

Sabbie A. Miller, Arpad Horvath, and Paulo J. M.
Monteiro, “Readily Implementable Techniques Can Cut
Annual CO2 Emissions from the Production of Concreteby over 20%,” Environmental Research Letters 11, no. 7(2016): 074029, doi:10.1088/1748-9326/11/7/074029.

15

24

Monkman and MacDonald, “On Carbon Dioxide
Utilization as a Means to Improve the Sustainability of
Ready-Mixed Concrete.”

25“Solidia Cement:”

26

Claus Pade and Maria Guimaraes, “The CO2 Uptakeof Concrete in a 100 Year Perspective,” Cement andConcrete Research 37, no. 9 (September 1, 2007):
1348–56, doi:10.1016/j.cemconres.2007.06.009.

27

Ibid.

28

Monkman and MacDonald, “On Carbon Dioxide
Utilization as a Means to Improve the Sustainability of
Ready-Mixed Concrete.”29

16

Hsien H. Khoo and Reginald B.H. Tan, “Life
Cycle Evaluation of CO2 Recovery and Mineral
Sequestration Alternatives,” Environmental Progress
25, no. 3 (October 1, 2006): 208–17, doi:10.1002/
ep.10139; Hsien H. Khoo et al., “Carbon Capture andMineralization in Singapore: Preliminary Environmental
Impacts and Costs via LCA,” Industrial & Engineering
Chemistry Research 50, no. 19 (October 5, 2011):
11350–57, doi:10.1021/ie200592h; Experience
Nduagu, Joule Bergerson, and Ron Zevenhoven,“Life Cycle Assessment of CO2 Sequestration in
Magnesium Silicate Rock – A Comparative Study,”
Energy Conversion and Management 55 (March 2012):
116–26, doi:10.1016/j.enconman.2011.10.026; Abby
Kirchofer et al., “Impact of Alkalinity Sources on theLife-Cycle Energy Efficiency of Mineral Carbonation
Technologies,” Energy & Environmental Science 5, no. 9(2012): 8631–41, doi:10.1039/C2EE22180B.
30

Kirchofer et al., “Impact of Alkalinity Sources on theLife-Cycle Energy Efficiency of Mineral Carbonation
Technologies.”

31

Nduagu, Bergerson, and Zevenhoven, “Life Cycle
Assessment of CO2 Sequestration in Magnesium Silicate
Rock – A Comparative Study.”

32

Kirchofer et al., “Impact of Alkalinity Sources on theLife-Cycle Energy Efficiency of Mineral Carbonation
Technologies.”

33

Ibid.

34

Scrivener, John, and Gartner, “Eco-Efficient Cements:
Potential, Economically Viable Solutions for a Low-CO2,
Cement-based Materials Industry.”

November 2017

Chapter 3:

refining. Commodity chemicals, such as methanol,
can also be finished products in themselves. As Figure
3.1 illustrates, there are many different direct andindirect routes by which CO2 can be converted into
a commodity chemical, some of which pass throughsynthesis gas (syngas).3

Commodity
ChemicalsCommodity chemicals are one of the CO2-based
products considered in the roadmap because of thewide range of market opportunities, the possibility toscale up relatively mature technologies for commercial
production in the medium-term, and the challenges
in assessing the climate benefits of myriad production
pathways and products. In this section, we review thetechnical challenges and R&D needs associated withthe main conversion pathways, examine three example
products, and look at issues in lifecycle assessment forcommodity chemicals.

Today well over 350 Mt of organic chemicals—in theform of solvents, synthetic rubber, fiber, plastics andother products—are manufactured each year fromfossil fuels.1 Production of these organic chemicals
results in approximately 2 GtCO2 of CO2 emissions
from the direct and indirect use of fossil fuels.2
Substitution of even a small fraction of this very large
flow of materials and fuels represents an important
opportunity for CO2 utilization. While this large flow iscomposed of myriad products, the precursors to thefinished products—i.e. commodity chemicals—are
fewer and individually larger in production volumes(Figure 3.1).

Technology and energy challenges
Carbon dioxide is a very stable, non-reactive molecule.
As a gas (at standard temperatures and pressures)it has a lower energy than most other feedstocks
used in industrial chemistry, meaning that it will notreact to form other chemicals unless energy—often
a substantial amount—is supplied to the process

Examples of these commodity chemicals include
ethylene, propylene, methanol, butadiene andpolyvinyl chloride. Typically, these chemicals have
low profit margins, and thus use highly efficient
production chains that are closely tied to petroleum
Section 2.2
TC
EC
PC

Raw Materials
Carbon dioxide
Hydrocarbons
Hydrogen
Water

Commodity
Chemicals

TC
EC
PT

SyngasTC

CarbonmonoxideHydrogen

BIO

MethaneMethanolFormic acid
Dimethyl ether
Alkanes(e.g. ethane)
Alkanes(e.g. ethylene)

TC

BIO

Commodity
Chemicals
MethaneMethanolFormic acid
Dimethyl ether
Alkanes(e.g. ethane)
Alkanes(e.g. ethylene)

BIO

Figure 3.1. Direct and indirect routes (via synthetic gas, or syngas) for the conversion of raw materials tocommodity chemicals, showing the multiple pathways that can be employed, linkages between commodity
chemicals and finished products, and the scope of the chapter (in dashed lines). Pathway abbreviations are:thermocatalytic (TC), electrochemical (EC), photochemical (PC), photothermal (PT), and biological (Bio).
November 201717

(Figure 3.2).4 This means that there are relatively few
thermodynamically favorable reactions other thanthe carbonates discussed in Chapter 2 where CO2
is a reactant, rather than a product. To use CO2 as areactant in the production of commodity chemicals
generally requires energy to be added into the system,in the form of heat and electricity.
The amount of energy that must be added to createcommodity chemicals from CO2 depends on thechange in the carbon atom’s oxidization state. When
CO2 is incorporated into an organic molecule without achange in oxidization state (e.g. to make carboxylates,
carbonates and carbamates), the amount of energythat must be added is small (see Figure 3.2).5 On theother hand, when CO2 is chemically reduced throughthe addition of hydrogen (e.g. to make methanol
or methane) the amount of energy that is added
is quite large (in the form of process heat and theenergy required to generate hydrogen). All otherthings being equal, synthesizing products from CO2that contain oxygen (e.g. aldehydes, carboxylic acids)
requires significantly less energy than synthesizinghydrocarbons (e.g. alkanes, alkenes).
The fact that energy must be supplied for synthesis
reactions involving CO2 is not a problem, per se, as
many common chemical processes, such thermal
cracking of ethane to produce ethylene, require

external energy to be supplied.7 However, mostof the energy required to drive these reactions
typically comes from combustion of a portion of thefossil-based feedstock (or other fossil fuel) to provide
heat.8 In CO2 synthesis reactions, this energy must be
provided from another source, which must have arelatively low-carbon intensity in order to provide an
overall climate benefit (see “Example Pathways”).
As an example, Bennett et al. estimate that
thermocatalytic production of ethylene from CO2
and water (as a hydrogen source) would require aminimum input of 13.1 MWh of heat and electricity
per ton of ethylene.9 Making all 32 Mt of ethylene
produced in North America in 2016 from CO2 would,
thus, require over 423 TWh of electrical and thermalenergy. If this use of CO2 is to contribute to emissions
reductions, the electricity and heat required would
have to come from low-carbon sources. This would be
the equivalent of consuming 1% of the total primaryenergy supply (TPES) for North America in 2016 or—more appropriately—about 5% of the total renewable
and nuclear energy supply to make only ethylene.10

Multiple technology pathways exist forCO2 conversion
Conversion pathways can be grouped into four broad
categories:11■■ Thermocatalytic: where energy is provided in the200

Gibbs Free Energy (KJ/mole)

0

-200

C6H6 (g) (+130)

C6H6 (l) (+124)
C2H4 (g) (+68)
H2 (l) (+18)
H2 (g) (0)C6H14 (l) (-4)
NH3 (g) (-16)
CH4 (g) (-51)
HCHO (l) (-102)
CH3OCH3 (g) (-113)
CH3OH (l) (-166)
CO (g) (-137)
H2O (l) (-228)
H O (g) (-237)2-400

CO2 (g) (-394)

NH2CONH2 (s) (-197)
NiO (s) (-212)
C6H5COOH (s) (-245)

HCOOH (l) (-361)
CO2 (l) (-386)
CO3= (l) (-528)-600

C-graphite (s) (0)Ni (s) (0)HCO3- (l) (-586)
C2O4= (l) (-671)

Nl(OH)2 (s) (-447)
NiCO3 (s) (-613)

-800

-1000
CaCO3 (s) (-1130)-1200

Gibbs Free Energy ∆Gºr (KJ/mole) (State, G: gas; L: liquid; S: solid)

Figure 3.2. Free energy of formation for CO2 andselected reaction products.6.
18

form of heat (and pressure) and the reaction isfacilitated by a catalyst;■■ Electrochemical: where energy is provided in theform of electrons and products are generated in anelectrochemical cell;12■■ Biochemical: where living organisms or components
thereof (e.g. enzymes) reduce CO2 to products;■■ Photochemical: where solar energy directly provides
thermal or, via an intermediate material, electricalenergy; and,■■ Hybrid approaches: where pathways are combined(e.g. electrolysis coupled with Fisher-Tropsch
synthesis, microbial electrolytic cells, solar-thermal
conversions).13
The two primary thermocatalytic pathways are:direct hydrogenation of CO2, and reduction of CO2 tocarbon monoxide followed by Fischer-Tropsch (F-T) or
methanol synthesis (Figure 3.1). The chemistry of thedirect hydrogenation route is generally well-known andNovember 2017

BOX 3.1 Commercial Methanol

Production from CO2

The first CO2-to-methane facility, known as the George Olah Renewable Methane Plant, was designed, built
and is operated by Carbon Recycling International (CRI) in Reykjanes, Iceland (see image below). It wascommissioned in 2012 with a capacity of 1000 t/y of methanol (1.3 million liters) and was expanded to
4,000 t/y (5 million liters) in 2015.14 The CO2 feedstock for the process is captured
from a neighboring geothermal power plant, where it is a co-product of steam
extraction for geothermal energy. Hydrogen is generated via electrolysis using
low-carbon Icelandic grid electricity, and is used to directly hydrogenate thecaptured CO2 to methanol using a heterogenous catalyst.15 The product,
which CRI has branded “Vulcanol,” is then sold for use as a gasoline additive
and as a feedstock for biodiesel production. The overall process has a low
emissions footprint because of the extremely low emissions of the Icelandic
grid; without this, the production of hydrogen for the process would likely
result in very high overall emissions.
Image courtesy of CRI

has been commercialized for production of methane,methanol and dimethyl ether (in one step) from CO2.
Production of methanol from CO2 has been tested atpilot scale by companies such as Mitsui and, today,
a 5-million-liter-per-year CO2-to-methanol plant is
operating in Iceland (Box 3.1). Some view methanol
as an excellent platform chemical for a CO2-based
economy, as efficient commercial processes exist toconvert methanol to gasoline, olefins (e.g. ethylene,
propylene), and dimethyl ether (in a two-stepprocess).16 In practice, R&D challenges for directhydrogenation include CO2 activation, which requires
better catalysts; and, low yields, which could be
mitigated via more efficient separations.
Alternatively, F-T synthesis— that is, the conversion ofcarbon monoxide and hydrogen into hydrocarbons—isvery well-known, having been discovered in the
1920s, commercialized during World War II, and usedindustrially today.17 Commercial F-T processes arecommonly used to produce “syncrude,” which contains
a wide range of hydrocarbons. The challenge for thisroute is reducing CO2 to carbon monoxide, which is thefeedstock for F-T synthesis. Options include the reverse
water gas shift (RWGS) reaction, the forward version ofwhich is used today in hydrogen production from fossil
fuels; and, dry,18 bi-19 and tri-reforming20 processes,
which use methane (or other light hydrocarbons) toNovember 2017

reduce CO2. Fundamental advances (e.g. lowertemperature catalysts, combining RWGS withseparations) are required to commercialize RWGS and
CO2 reforming processes. In the case of CO2 reforming,
the use of fossil hydrocarbons means that it will bedifficult to achieve significant emissions reductions
relative to conventional synthesis from pathways
in which this technology is employed—unlessbiomethane is used. Many other thermocatalytic
options, such as chemical looping cycles, have also
been proposed but are largely theoretical at thistime.21
Most of the thermocatalytic pathways shown in
Figure 3.3 could involve an electrochemical step (i.e.
electrolysis of water to generate hydrogen), making a
hybrid process. In contrast, one-step electrochemical
processes which convert CO2 to commodity chemicals
are rare. Laboratory and pilot-scale research has
demonstrated the electrochemical reduction of CO2
to, for example, formic acid using a range of metalelectrodes (e.g. tin, indium, cadmium), methanolusing ruthenium and titanium, methane using goldor copper, and ethylene using copper electrodes.22
In addition, the low-temperature electroreduction of
CO2 to CO (which differs from the SOEC route) has also
been demonstrated, and could be a step in a hybrid
electro-thermocatalytic process.23 Startup companies

19are active in this space,24 but the technology has not
yet reached the pilot stage.
Multiple challenges must be overcome in one-step
electrochemical pathways, including: low faradic

efficiency,25 particularly due to competing hydrogen
evolution in aqueous solvent systems for strongly
reduced products (e.g. methanol and methane); lowcurrent density, and hence production rates; andBOX 3.2 Making the hydrogen needed

to convert CO2 to chemicals

Production of hydrogen—shown below in Figure 3.3—is a key step in both the direct and RWGS
thermocatalytic routes for the conversion of CO2 to chemicals, as well as in some electrochemical routes.
Today, approximately 50 Mt of hydrogen are produced each year, over 95% of which is produced fromfossil fuels, primarily through steam-methane reforming (SMR).26 State-of-the-art SMR processes are highly
efficient (>80% HHV), and generate a relatively high CO2 concentration exhaust that is usually vented to theatmosphere. In principle, this CO2 could be captured relatively easily and stored to reduce the carbon footprintof the produced hydrogen.27 As of mid-2017 there are two operating SMR projects that capture and store CO2:
one in Canada28 and another in the United States.29

The remaining 4% of global hydrogen production comes from small-scale electrolysis30 of water. Electrolysis is
a proven process that is extremely efficient (>80% HHV) and can be carried out via alkaline electrolysis (AEL),
proton exchange membrane (PEM), and solid oxide (SOEC) electrolysis. Both AEL
and PEM electrolysis units are commercially available, and while AEL systems
have a longer track record, PEM systems are more flexible and efficient.31
SOEC systems are still in the development stage but appear attractive forCO2 conversion due to the possibility of co-electrolysis (direct productionof syngas streams) and heat integration with F-T synthesis.32 In 2015, theInternational Energy Agency published a technology roadmap for hydrogenproduction (and fuel cells) that lays out goals and milestones for developmentof both electrolysis and production of hydrogen from fossil fuels with CCS.

DME
Direct Reaction
CO2 + H2

CO2

CH4
CH3OH

Syngas Routes
CH4
CH4 Reforming + WGS
CH4 + 2H2O g CO2 + 4H2

Electrolysis

2H2O + 4e- g 2H2 + O2

H 2O

H2

Alkanes

CO2 Reforming Processes
CO2 + CH4 g 2CO + 2H2

Fischer-Tropsch
CO + H2RWGS
CO2 + H2 g CO + H2O

Syngas-to-Methanol
CO + 2H2 g CH3OH

Alkenes

Co-Electrolysis
2CO2 + e- g 2CO + O2
2H2O + 4e- g 2H2 + O2

CO2 (to Geological Storage)

Figure 3.3. Selected thermocatalytic (and hybrid thermo-electrochemical) routes from CO2 and water or methane
to commodity chemicals.
20

November 2017

poor stability of the electrodes. R&D in this space isneeded to better understand the impacts of electrodestructure on improving rates and stability, elucidate thefundamental relationships between the mechanisms
of CO2 reduction and electrode materials andstructure, and develop improved design for practicalapplications (e.g. the use of gas diffusion electrodes
to overcome mass transport limitations and reduce
the separation costs associated with low yields).33
One other promising area of active research relating
to electrochemical pathways are “hybrid” microbial
electrolysis cells, in which microbial communities livingin the electrochemical cell reduce CO2 to chemicals.34
The predominant biological pathway for reduction of
CO2 to products is photosynthetic—the productionof glucose from CO2 in the presence of sunlight.
Conversion of biomass to energy and materials has
played a critical role in the development of society,and bioenergy crops—including algae—will likely playa larger role in the future as a means of addressing
climate change.35 While biomass pathways are notin the scope of this roadmap, non-photosynthetic
biological pathways for the conversion of CO2 directly
to products are. These pathways use autotrophic
organisms, which consume carbon monoxide,hydrogen, and CO2 to generate reduced carbon
molecules, such as ethanol or acetate.36 At least one
bioprocess that uses bacteria for the fermentation ofsynthesis gas streams to ethanol and butanediol has
been demonstrated at the 300 t/y scale,37 and larger
facilities (on the order of 10,000 t/y) based on theprocess are in development.
An important benefit of biological pathways is thatthey operate under mild conditions and the organisms
can be engineered to directly produce a range oforganic chemicals that otherwise require multiple
steps to produce from commodity intermediates(or cannot be synthesized industrially). Two notabledrawbacks of such systems are that they usuallyrequire sterile conditions to avoid contamination
and are difficult to hybridize with thermochemical
pathways, the latter being the predominant means of
producing syngas today.
The last standalone category is photochemical
pathways, which come in two main types: thermal,
where light is focused on a high-temperature reactor
to reduce CO2,38 and catalytic, where a catalyst
in solution or solid semiconductor absorbs light,
November 2017

creating electrical energy which can reduce CO2.39
Photothermal pathways share much in common
with the thermochemical pathways described above,with the additional complication that the process
must be integrated with a solar collector and suffer
the disadvantage of variable solar energy input.
Photocatalytic pathways have been studied since the1970s and, at the laboratory scale, have been shown
capable of reducing CO2 to formic acid, methanol,and methane. However, the efficiency and production
rates of photocatalytic pathways remain too low to
be commercially relevant, and don’t show a trend
towards improvement (Figure 3.4).40 A fundamental
breakthrough is required if photocatalytic pathways
are to become commercially relevant.

Consistent lifecycle assessments for CO2
conversions remains a challenge
A robust life cycle assessment (LCA) framework isneeded to determine whether a certain use of CO2 canbring about a climate benefit – an overall reductionin emissions relative to an alternative, or even net
negative emissions – and to quantify such benefits.41
The results of lifecycle assessments for commodity
chemicals are important in several contexts. Results of
LCA studies can help guide R&D expenditures towards
products and processes that have the largest emissions
reduction benefit and can be used to focus R&D on
challenges that, if addressed, can have the largest
possibility for improvement. They are also particularly
important in informing decisions to incentivize (orinvest in) production of a CO2-based product and, if
so, the appropriate level of the incentive. Finally, theenvironmental footprints of products can inform andinfluence consumer decision-making, even in theabsence of policy.
In the LCAs performed to date, there areinconsistencies that make comparisons between
various CCS and CO2U options difficult,42 and thecommon pitfalls and limitations of LCA for organic
chemicals have been comprehensively assessed
elsewhere.43 In summary, the main challenges in LCA
for commodity chemicals are:■■ The products of CO2 utilization cannot easily becompared because they are not equivalent, nor
are their uses. Thus, where comparisons are being
made, the basis for comparison (i.e. the “functionalunit”) must be chosen carefully. Moreover, the21

CH4 formation rate/µmol g-1cat h-1

35
30
25
20
15
10
5
0

1985

1990

1995

Year

2000

2005

2010

2015

Figure 3.4. Rates of photocatalytic CO2 conversion to methane reported in selected studies over time, as collectedby Kondratenko et al.,44 showing the limited progress that has been made to date in photocatalysis.
objective of the LCA may not always be served witha functional unit that is defined in terms of the
product; rather, it could be in terms of an input suchas units of CO245 or hydrogen consumed.46■■ Commodity chemicals typically serve as feedstocks
for other production processes that generate
multiple finished products. Allocating the lifecycle
emissions in multiple product systems such asthese is not a new problem in LCA, but always achallenging one to solve.
■■ The products made from commodity chemicals areoften used and disposed of in a range of different
ways (e.g. reused, recycled, incinerated). Where
products are long-lived or, at the end of life,
disposed of in such a way that the carbon does not
return to the atmosphere, they effectively sequester
CO2; conversely, assessing the climate benefits ofproducts where CO2 is temporarily sequestered ismore difficult.47 In theory, products that are longlived and retain carbon over extended periods oftime should have a benefit over those that areshort-lived (e.g. fuels); however, LCA usually doesn’t
account for temporal distribution of impacts by
convention (see Chapter 5 for a deeper discussion).
■■ The spatially varying carbon intensity of electricity
and hydrogen inputs mean that results for
22

production in one region of the world cannot always
be easily compared with another. For example, thegrid electricity mix between neighboring countries
dramatically impacts the emissions benefit of a rangeof single-carbon chemicals in Europe (Figure 3.5).48■■ The emission footprint of differing CO2 feedstocks
is variable and uncertain.49 Although sources ofhigh-concentration CO2 are found in many chemical
conversion facilities, most CO2 sources are diluted
and require concentration through separations. The
environmental burdens associated with CO2 capture
may be substantial in comparison to those relating
to CO2 conversion (e.g. from an energy perspective,
Kondratenko et al. present an example in which 60%of the total energy required to produce formic acidfrom CO2 is due to CO2 capture using amines).50 In
many cases, production chains do not result in net
negative emissions, but an emissions benefit comesthrough the substitution of fossil-based productswith lower carbon-intensity products. In such cases,
the climate benefit of such displacements could be
expected to decrease over time as climate policies“force out” the higher carbon-intensity products
from the market.

November 2017

In addition, it is important to recall that, while thefocus of this discussion is on the use of LCA to assessclimate benefits, the use of CO2-based production
pathways can also have wider environmental
implications that should be considered. One prominent
example is the production of dimethyl carbonate(DMC) via urea versus phosgene, in which the urea
route—although not practiced industrially—was
shown to have substantial benefits across a range ofenvironmental impacts.52

CH4

CH2OH
CO
HOOOH
CH4

CH2OH
CO
HOOOH

CH4

CH2OH
CO
HOOOH

CH4

CH2OH
CO
HOOCH

–
°
*

Example pathways

CH4

As the review in the preceding section illustrates,
the number of possible combinations of technology
pathways and products is very large. In this section,
we describe three product pathways on the basis ofmarkets, technologies and environmental impact.
These pathways are described in Table 3.1.

CH2OH
CO
HOOOH

CH4

CH2OH
CO
HOOOH

Figure 3.5. European countries where CO2-based
processes have the potential to achieve lower
emissions impacts than fossil-based processes (ingreen and yellow) by using the national electricity mix
of 2012 and an electrolysis unit with an efficiency of
50 kWh per kg H2.51

The most advanced pathway is from CO2 to methanol
via direct hydrogenation of CO2. While this is being
undertaken commercially (as illustrated in Box 3.1),
the largest facility is hundreds of times smaller
than existing natural gas-based plants, which havecapacities upwards of 5000 t/d. Thus, the technologies
involved require further scale-up, by increasing

Table 3.1. Example pathways across markets and TRL’s.
CO2-Based Product
MethanolFormic Acid

Ethylene

MarketSize (Mt/y)70 (2015)
100 (2020)53

0.65 (2014)54

180 (2017)55

Technology

Price (USD/t)
Pathway$400
Thermocatalytic(Directhydrogenation)
Technology
demonstration (6)CRI, Mitsui, Solvay$1000Electrocatalytic$900
Electrocatalytic

Development Stage(TRL)
Developers
Environmental
ImpactNovember 2017

Greenhouse Gas
68-137 (avoided)56
Emissions (MtCO2/y)Laboratory pilot (3)Laboratory studies(2)
DNV, Mantra Energy, Opus12
IFPEN
1-3 (avoided)57
Unknown

23

unit size, modular manufacturing capacity or somecombination thereof. The economics of CO2-based
methanol production are difficult, however, as theestimated production cost is at least twice the current
market price (even in an optimal case, where CO2 isprovided for free).58 If current fossil-based methanol
production was fully substituted for CO2-based
methanol—produced using electrolytic hydrogen andlow-carbon electricity (i.e. approximately 50 gCO2/
kWh)—it would result in the avoidance of on the orderof 100 MtCO2/y.59 This implies an avoidance cost ofover $800/tCO2.60

Roadmap considerations

Both formic acid and ethylene production via
electrolysis are at earlier stages of development, withthe former having been tested at laboratory scale(i.e. kg/d) while the latter has only been observedin laboratory studies. Electrochemical production of
formic acid using low-carbon electricity appears to bea promising option for emissions reduction; however,the small market size limits the cumulative emissions
reduction to a few millions of tons per year.61 In
contrast to methanol, the estimated production cost offormic acid is comparable to the current market price,and the avoidance cost is approximately $30/t.62 Dueto the very early stage of technology development,
lifecycle and techno-economic assessments of theCO2-based production of ethylene (via any route) have
not yet been published.

Key findings and recommendations

Given the wide range of potential products, multitudeof pathways between CO2 and any single product,
and the wide range of development levels acrosspathways, it is unlikely that any single roadmap could
cover the space. However, continued innovation in
CO2 conversion to commodity chemicals would benefit
from development of roadmaps that target narrowergroupings of products or technologies. Figure 3.6
lays out an example of such milestones for catalysis
advances and their relative sequence.

Findings
Conversion of CO2 to commodity chemicals isdaunting because of the energy-intensive nature of
CO2 reduction. However, not all products are equal interms of their energy requirements: those where CO2
is less deeply reduced (e.g. formic acid, formaldehyde,
methanol) are relatively easier than alkanes (e.g.
methane, ethane) or alkenes (e.g. ethylene).
Demonstrated, commercially relevant thermocatalytic
conversion pathways exist for production of methanol,
dimethyl ether and methane from CO2. However,these pathways require a low-carbon hydrogensource, either via reforming of fossil fuels with CCS
or electrolysis of water using low-carbon electricity.
Hybrid thermocatalytic pathways, such as co-reforming

Fully commercialized(5-20 years)

Create R&D funding
programs to
supportfundamental
breakthroughs

Support R&D,
and pilot testing for
new catalysts andassociatedprocesses

Supportdemonstration of
new processes

Update LCA studies
based on emerging
results; steer
research directions

Confirm LCA
results at pilot &demonstration
plant scales

Publish standards
for CO2-based
chemical pathways

Certify CO2-based
commodity
chemical pathways

TECHNOLOGY

Long-term(4-15 years)

Identify pathways
needing fundamental advances incatalysis

EMISSIONS

Medium-term(2-8 years)

Identify mostpromisingpathways using
LCA

STANDARDS

Near-term(1-3 years)

Identify where newor amended
standards areneededInitiate thestandards making
process at the ISO(or national) levels

Figure 3.6. Conceptual roadmap for accelerating the innovation of CO2 conversion to commodity chemicals.
24

November 2017

using SOEC coupled with F-T or methanol synthesis,
and fermentation of thermally (or electrochemically)
produced syngas also appear promising.
Electrochemical reduction of CO2 is a rapidly advancing
field, and the production of carbon monoxide andformic acid seem to be relatively advanced comparedto other products (e.g. methanol, methane, ethylene).
The climate benefit of producing commodity chemicals
from CO2 depends critically on the carbon intensityof the inputs—hydrogen, CO2, heat, and electricity—which will vary depending on the production pathway
and geographic location of the process. Commodity
chemicals which have a greater potential to be used in
durable products (as opposed to fuels) will have a larger
benefit, as will those that displace carbon-intensive
production pathways (e.g. methanol from coal).

Recommendations
Targeted R&D activities in the following areas would
likely accelerate commercialization and improve
performance for CO2 conversion to industrial chemical
feedstocks:■■ Better catalysts would be inherently more efficient,and would reduce energy costs, improve yields,
and improve emissions footprint. Rational designof catalysts (e.g. using computational DFT-based
techniques) for thermo- and electrochemical
pathways appear to be a priority.
■■ As renewable electricity becomes cheaper andprovides a larger share of the grid electricity mix,
electrochemical pathways become more attractive
for the upgrading of CO2. Modeling of CO2 activation
on metal surfaces for electrochemistry, innovations
to improve electrode stability, and development of
new cell designs are important targets for R&D.63■■ Advances in the fundamental understanding of hightemperature electrolysis (e.g. SOEC) are required,along with advances in materials to allow reliable,
long-duration operation of SOEC cells.
■■ The combination of commercially available
thermocatalytic pathways with emerging electroor biochemical processes to create hybrid systems
appears to be a promising strategy to advanceCO2 conversions64 and modeling to evaluate thetechnical, economic and environmental performanceis needed to drive innovation in this area. The
combination of separations with reactions, long a
November 2017

goal for chemical engineering research, would beparticularly helpful to improve yields in all pathways.
■■ Innovative approaches are needed to advancephotocatalysis and investments should focus on longterm R&D. In addition, practitioners should aim to
make studies more consistent and comparable bothin experimental design (e.g. light sources), but alsoin presentation of results (e.g. by providing better
information on quantum yield or efficiency).65■■ There are few examples of life-cycle assessments
for commodity chemicals today, and those thatexist are difficult to compare. Additional studies
are required to better define the potential climate(and environmental) benefit of the wide rangeof conversion pathways and products, and thesestudies should follow a consistent approach that
improves their comparability.
Much remains to be understood regarding thechemical conversion approaches and life-cycle
implications for a CO2-to-chemicals enterprise. Whilesome processes are near commercial, the possibilities
to improve cost, performance, and emissions footprint
are real. A coordinated innovation agenda in this space
is a priority since many technical advances are new,many opportunities exist to improve, the technicalreadiness range is large, and the potential for climate
benefits is high.
1

D. Saygin et al., “Assessment of the Technical andEconomic Potentials of Biomass Use for the Productionof Steam, Chemicals and Polymers,” Renewable andSustainable Energy Reviews 40 (December 2014):
1153–67, doi:10.1016/j.rser.2014.07.114.

2

Total emissions from the “chemical” sector, excluding
emissions from products used in agriculture asreported by: Bojana Bajželj, Julian M. Allwood, andJonathan M. Cullen, “Designing Climate Change
Mitigation Plans That Add Up,” Environmental Science& Technology 47, no. 14 (July 16, 2013): 8062–69,
doi:10.1021/es400399h.

3

For the purpose of this discussion, we take a slightly
different tack than the first version of the CO2U
Roadmap in that we don’t treat syngas as a commodity
chemical, but rather as an integral step in the
production of commodity chemicals.

4

At low temperature and high pressure, carbon dioxide
exists as a liquid, and has a higher energy than a small
25

number of industrially relevant chemicals. However,energy must be supplied to reach these temperaturesand pressures, generally eliminating any energy
advantage unless there is an opportunity to capture
CO2 directly from high pressure systems.

Because the products are evolved separately at theanode and cathode, no separations are required in an
ideal process.
13

While not disused here, other approaches show somepromise. For example, see Ji-Jun Zou and Chang-Jun
Liu, “Utilization of Carbon Dioxide through Nonthermal
Plasma Approaches,” in Carbon Dioxide as ChemicalFeedstock (Wiley-VCH Verlag GmbH & Co. KGaA, 2010),
267–90, doi:10.1002/9783527629916.ch10.

5Michele Aresta, Carbon Dioxide as Chemical Feedstock(John Wiley & Sons, 2010).

6

Chunshan Song, “CO2 Conversion and Utilization: An
Overview,” in CO2 Conversion and Utilization, vol. 809,
0 vols., ACS Symposium Series 809 (American Chemical
Society, 2002), 2–30, http://dx.doi.org/10.1021/bk2002- 0809.ch001.

14

CRI, “George Olah Plant,” Carbon Recycling
International, February 14, 2016, http://
carbonrecycling.is/georgeolah/.

7

Ibid.

15

8

U.S. DOE, “Manufacturing Energy and Carbon Footprint
for Chemicals Sector (NAICS 325),” U.S. Departmentof Energy, 2014, https://energy.gov/eere/amo/
downloads/chemicals-2010-mecs.

Olah, “Towards Oil Independence Through Renewable
Methanol Chemistry.”16

George A. Olah, “Beyond Oil and Gas: The Methanol
Economy,” Angewandte Chemie International Edition
44, no. 18 (April 29, 2005): 2636–39, doi:10.1002/
anie.200462121; George A. Olah, “Towards Oil
Independence Through Renewable Methanol
Chemistry,” Angewandte Chemie International Edition
52, no. 1 (January 2, 2013): 104–7, doi:10.1002/
anie.201204995.

17

Arno de Klerk, Fischer-Tropsch Refining (Weinheim:
Wiley-VCH, 2011).

18

Devendra Pakhare and James Spivey, “A Review ofDry (CO2) Reforming of Methane over Noble Metal
Catalysts” 43, no. 22 (October 20, 2014): 7813–37,
doi:10.1039/C3CS60395D.

19

George A. Olah et al., “Bi-Reforming of Methane fromAny Source with Steam and Carbon Dioxide Exclusively
to Metgas (CO–2H2) for Methanol and Hydrocarbon
Synthesis,” Journal of the American Chemical Society
135, no. 2 (January 16, 2013): 648–50, doi:10.1021/
ja311796n.

20

Song, “CO2 Conversion and Utilization.”

21

Christopher Graves et al., “Sustainable Hydrocarbon
Fuels by Recycling CO2 and H2O with Renewable
or Nuclear Energy,” Renewable and Sustainable
Energy Reviews 15, no. 1 (January 1, 2011): 1–23,
doi:10.1016/j.rser.2010.07.014.

22

Emily Barton Cole and Andrew B. Bocarsly,“Photochemical, Electrochemical, andPhotoelectrochemical Reduction of Carbon Dioxide,”in Carbon Dioxide as Chemical Feedstock (WileyVCH Verlag GmbH & Co. KGaA, 2010), 291–316,
doi:10.1002/9783527629916.ch11; Jinli Qiao et al.,“A Review of Catalysts for the Electroreduction of

9Bennett et al. consider two different pathways for
ethylene production: generation of hydrogen fromelectrolysis followed by direct reaction and a second
pathway corresponding to reverse water gas shift toproduce CO followed by Fischer-Tropsch synthesis.
Simon J. Bennett, David J. Schroeder, and Sean T.
McCoy, “Towards a Framework for Discussing andAssessing CO2 Utilisation in a Climate Context,”
Energy Procedia, 12th International Conference on
Greenhouse Gas Control Technologies, GHGT-12,
63 (January 1, 2014): 7976–92, doi:10.1016/j.
egypro.2014.11.835.

10

IEA, “IEA - Statistics,” International Energy Agency,
accessed August 23, 2017, https://www.iea.org/
statistics/statisticssearch/.

11

M. Mikkelsen, M. Jorgensen, and F. C. Krebs,“The Teraton Challenge. A Review of Fixation
and Transformation of Carbon Dioxide,” Energy& Environmental Science 3, no. 1 (2010): 43–81,
doi:10.1039/b912904a; Evgenii V. Kondratenko etal., “Status and Perspectives of CO2 Conversion into
Fuels and Chemicals by Catalytic, Photocatalytic andElectrocatalytic Processes,” Energy & Environmental
Science 6, no. 11 (2013): 3112–35, doi:10.1039/
C3EE41272E.

12

26

An electrochemical cell separates reduction, which
occurs at the cathode, from oxidization reactions,which occur at the anode. Electrons travel throughan external circuit connecting the anode and cathode(i.e. the electrodes), while ions travel through a semipermeable membrane between the two “half-cells”.

November 2017

Carbon Dioxide to Produce Low-Carbon Fuels,”
Chemical Society Reviews 43, no. 2 (2014): 631– 75,
doi:10.1039/C3CS60323G.
23

Barton Cole and Bocarsly, “Photochemical,
Electrochemical, and Photoelectrochemical Reductionof Carbon Dioxide.”24

For example, Opus 12 (https://www.opus-12.com/)

25

Faradaic efficiency is the ratio of the actual andtheoretical amounts of a product formed based on
charge passed. A 100% faradaic efficiency means that
all of the electricity put into the system has gone into
the production of that product.

26

IEA, “Technology Roadmap: Hydrogen and Fuel Cells”(Paris, France: International Energy Agency, 2015),
https://www.iea.org/publications/freepublications/publication/technology-roadmap-hydrogen-andfuelcells. html.

27

28

29

30

IEAGHG, “Techno-Economic Evaluation of SMR BasedStandalone (Merchant) Hydrogen Plant with CCS” (IEA
Greenhouse Gas R&D Program, 2017), http://ieaghg.
org/exco_docs/2017-02.pdf.
Shell, “CCS Facility Exceeding Expectations,” Shell
Canada, accessed August 25, 2017, http://www.
shell.ca/en_ca/about-us/projects-and-sites/
quest-carbon-capture-and-storage-project/carboncapture- and-storage.html.
U.S. DOE, “Texas CO2 Capture Demonstration
Project Hits Three Million Metric Ton Milestone,”
U.S. Department of Energy, accessed August25, 2017, https://www.energy.gov/fe/articles/
texas-co2-capture-demonstrationproject- hits-threemillion-metric-ton-milestone.
Manuel Götz et al., “Renewable Power-to-Gas: A
Technological and Economic Review,” Renewable
Energy 85 (January 2016): 1371–90, doi:10.1016/j.
renene.2015.07.066.

31

Gerda Gahleitner, “Hydrogen from Renewable
Electricity: An International Review of Power-to-Gas
Pilot Plants for Stationary Applications,” International
Journal of Hydrogen Energy 38, no. 5 (February 19,2013): 2039–61, doi:10.1016/j.ijhydene.2012.12.010.

32

Graves et al., “Sustainable Hydrocarbon Fuels by
Recycling CO2 and H2O with Renewable or Nuclear
Energy”; Yun Zheng et al., “A Review of High
Temperature Co-Electrolysis of H2O and CO2 to Produce
Sustainable Fuels Using Solid Oxide Electrolysis
Cells (SOECs): Advanced Materials and Technology,”

November 2017

Chemical Society Reviews 46, no. 5 (2017): 1427–63,
doi:10.1039/C6CS00403B.
33

V. Kondratenko et al., “Status and Perspectives of CO2
Conversion into Fuels and Chemicals by Catalytic,
Photocatalytic and Electrocatalytic Processes”; Qiao etal., “A Review of Catalysts for the Electroreduction of
Carbon Dioxide to Produce Low-Carbon Fuels.”

34

V. Kondratenko et al., “Status and Perspectives of CO2
Conversion into Fuels and Chemicals by Catalytic,
Photocatalytic and Electrocatalytic Processes”; Heming
Wang and Zhiyong Jason Ren, “A Comprehensive
Review of Microbial Electrochemical Systems as a
Platform Technology,” Biotechnology Advances 31,
no. 8 (December 1, 2013): 1796–1807, doi:10.1016/j.
biotechadv.2013.10.001.

35

Felix Creutzig et al., “Bioenergy and Climate Change
Mitigation: An Assessment,” GCB Bioenergy 7,
no. 5 (September 1, 2015): 916–44, doi:10.1111/
gcbb.12205.

36

Ivan A. Berg et al., “Autotrophic Carbon Fixationin Biology: Pathways, Rules, and Speculations,”in Carbon Dioxide as Chemical Feedstock (WileyVCH Verlag GmbH & Co. KGaA, 2010), 33–53,
doi:10.1002/9783527629916.ch3.

37

Derek W. Griffin and Michael A. Schultz, “Fuel andChemical Products from Biomass Syngas: A Comparisonof Gas Fermentation to Thermochemical Conversion
Routes,” Environmental Progress & Sustainable Energy
31, no. 2 (July 1, 2012): 219–24, doi:10.1002/ep.11613;
LanzaTech, “Facilities,” LanzaTech, accessed August 25,
2017, http://www.lanzatech.com/facilities/.

38

Ee Teng Kho et al., “A Review on Photo-Thermal
Catalytic Conversion of Carbon Dioxide,” Green
Energy & Environment, June 9, 2017, doi:10.1016/j.
gee.2017.06.003.

39

Barton Cole and Bocarsly, “Photochemical,
Electrochemical, and Photoelectrochemical Reductionof Carbon Dioxide”; V. Kondratenko et al., “Status
and Perspectives of CO2 Conversion into Fuels
and Chemicals by Catalytic, Photocatalytic andElectrocatalytic Processes.”40

V. Kondratenko et al., “Status and Perspectives of CO2
Conversion into Fuels and Chemicals by Catalytic,
Photocatalytic and Electrocatalytic Processes”;
Mikkelsen, Jorgensen, and Krebs, “The Teraton
Challenge. A Review of Fixation and Transformation of
Carbon Dioxide.”

27

41

Bennett, Schroeder, and McCoy, “Towards a Frameworkfor Discussing and Assessing CO2 Utilisation in a Climate
Context.”

50

V. Kondratenko et al., “Status and Perspectives of CO2
Conversion into Fuels and Chemicals by Catalytic,
Photocatalytic and Electrocatalytic Processes.”42

Rosa M. Cuéllar-Franca and Adisa Azapagic, “Carbon
Capture, Storage and Utilisation Technologies: A
Critical Analysis and Comparison of Their Life Cycle
Environmental Impacts,” Journal of CO2 Utilization 9(March 2015): 82–102, doi:10.1016/j.jcou.2014.12.001.

51

Ibid.

52

Michele Aresta and Michele Galatola, “Life
Cycle Analysis Applied to the Assessment of theEnvironmental Impact of Alternative Synthetic
Processes. The Dimethylcarbonate Case: Part 1,”
Journal of Cleaner Production 7, no. 3 (March 1999):
181–93, doi:10.1016/S0959-6526(98)00074-2.

53

Marc Alvardo, “The Changing Face of the Global
Methanol Industry,” IHS Chemical Bulletin, 2016.

54

Ibid.

55

Nandita Lal and James McKenna, “Will Europe’s
Bumper Steam Cracker Margins Be Sustained?,” Platts
S&P Global, accessed August 25, 2017, https://www.
platts.com/news-feature/2017/petrochemicals/globalethyleneoutlook/ europe-middle-east.

56

Guillaume Kerlero de Rosbo et al., “Valorisation
Chimique Du CO2: Etat Des Lieux – Quantification
Des Bénéfices Énergétiques et Environnementaux etÉvaluation Économique de Trois Voies Chimiques”(Angers, France: Agence de l’Environnement et de laMaîtrise de l’Energie, 2014), http://www.ademe.fr/
valorisation-chimique-co2-etatlieux- quantificationbenefices-energetiques-environnementaux-evaluationeconomique-trois-voies-chimiques.

57

Ibid.

58

Kerlero de Rosbo et al., “Valorisation Chimique Du CO2.”

59

Ibid.

60

Ibid.

61

Kerlero de Rosbo et al., “Valorisation Chimique Du CO2.”

62

Ibid.

63

V. Kondratenko et al., “Status and Perspectives of CO2
Conversion into Fuels and Chemicals by Catalytic,
Photocatalytic and Electrocatalytic Processes.”64

Gabriele Centi, Elsje Alessandra Quadrelli, and Siglinda
Perathoner, “Catalysis for CO2 Conversion: A Key
Technology for Rapid Introduction of Renewable Energy
in the Value Chain of Chemical Industries,” Energy& Environmental Science 6, no. 6 (2013): 1711–31,
doi:10.1039/C3EE00056G.

65

V. Kondratenko et al., “Status and Perspectives of CO2
Conversion into Fuels and Chemicals by Catalytic,
Photocatalytic and Electrocatalytic Processes.”43

André Sternberg, Christian M. Jens, and André Bardow,“Life Cycle Assessment of CO2-Based C1-Chemicals,”
Green Chemistry 19, no. 9 (May 8, 2017): 2244–59,
doi:10.1039/C6GC02852G; Niklas von der Assenet al., “Selecting CO2 Sources for CO2 Utilization by
Environmental-Merit-Order Curves,” Environmental
Science & Technology 50, no. 3 (February 2, 2016):
1093–1101, doi:10.1021/acs.est.5b03474; Niklas
von der Assen, Johannes Jung, and André Bardow,“Life-Cycle Assessment of Carbon Dioxide Captureand Utilization: Avoiding the Pitfalls,” Energy &Environmental Science 6, no. 9 (2013): 2721,
doi:10.1039/c3ee41151f.

44

V. Kondratenko et al., “Status and Perspectives of CO2
Conversion into Fuels and Chemicals by Catalytic,
Photocatalytic and Electrocatalytic Processes.”45

Cuéllar-Franca and Azapagic, “Carbon Capture, Storage
and Utilisation Technologies.”46

von der Assen et al., “Selecting CO2 Sources for CO2
Utilization by Environmental-Merit-Order Curves.”

47

Miguel Brandão et al., “Key Issues and Options inAccounting for Carbon Sequestration and Temporary
Storage in Life Cycle Assessment and Carbon
Footprinting,” The International Journal of Life
Cycle Assessment 18, no. 1 (June 2, 2012): 230–40,
doi:10.1007/s11367-012-0451-6; Francesco Cherubini
et al., “CO2 Emissions from Biomass Combustion for
Bioenergy: Atmospheric Decay and Contribution to
Global Warming,” GCB Bioenergy 3, no. 5 (October 1,2011): 413–26, doi:10.1111/j.1757-1707.2011.01102.x;
H. Herzog, K Calderia, and J. Reilly, “An Issue of
Permanence: Assessing the Effectiveness of Temporary
Carbon Storage,” Climatic Change 59 (2003): 293–310.

48

Sternberg, Jens, and Bardow, “Life Cycle Assessment of
CO2-Based C1-Chemicals.”49

von der Assen, Jung, and Bardow, “Life-Cycle
Assessment of Carbon Dioxide Capture and Utilization.”

28

November 2017

Chapter 4:

Durable Carbon
Materials
Introduction
The previous chapters examined CO2U technologies
that are near-to-market: already commercialized or
technologically mature enough to be commercialized
in the next decade. This chapter examines a CO2U
technology that is much farther from market, and iscurrently at the basic research stage: electrochemical
methods to convert CO2 directly into high-value solidcarbon materials, such as carbon nanotubes, carbon
fiber, graphene and diamonds (see Box 4.1).
There are two reasons to consider these far-frommarket products in this roadmap. First, the market forthese materials, particularly carbon fiber, is growing
rapidly.1 This is despite the fact that the current
manufacturing technology is expensive, limiting
commercial use to a small number of performancesensitive applications (e.g. light-weighting aircraft forfuel savings). Lower-cost production methods would
likely lead to even larger market growth. While it is too
early to tell whether CO2-based methods would resultin lower production costs, it is possible. This scenario
is very different from the situation for cement andchemical intermediates, in which CO2-based products
will generally have to compete with conventional
products in slower growing markets. Not surprisingly,
entering a growing market is likely to be easier thancompeting with conventional incumbent products in astatic market.
Second, this early-stage technology provides a casestudy of how policymakers can include emerging
technologies that are still at the basic research stage
in a comprehensive CO2U strategy. The policy needs
include funding support for basic research anddevelopment (R&D), some initial support for appliedresearch and technology development, progressively
detailed life-cycle emissions analyses (LCA), and early
coordination with standards and certification bodies.
This technology is not a good candidate for demandcreation policies such as tax incentives or mandates
for buyers, unlike some of the technologies discussed
earlier.
One concern that arises when discussing the carbon
materials market is that the total mass of carbon that
could be utilized is small, so the mitigation potentialof CO2-based durable carbon materials appears to below. However, by some estimates it may be as highas 1% of global emissions (when potential growth

BOX 4.1 Pure carbon can exist

in many different solid forms

The most well-known of these are diamond and graphite, which have both been used in commerce for
centuries. More recently, other forms of solid carbon have been produced, whose properties depend strongly
on their internal structure. Graphene is a single-layer hexagonal lattice of carbon atoms, and is an excellent
electrical conductor as well as being one of the strongest materials known. Carbon
nanotubes are seamless cylinders of graphene with diameters in the rangeof several nanometers; their strength and electrical properties have led toapplications in batteries, automotive, electronics, sporting goods, and manyother areas. Carbon fiber is a long, thin filament made primarily (although
not entirely) of carbon atoms. These fibers are typically combined with aplastic resin to form a composite material known as carbon-fiber-reinforced
polymer (CFRP, or sometimes just “carbon fiber”). This material has awide range of applications for aerospace, automotives, energy, concrete
reinforcement and sporting goods.

November 201729

in market demand is included),2 justifying serious
consideration within a climate strategy. Also, because
these materials are durable—unlike fuels and many
chemicals—they will not rapidly return carbon dioxide
to the atmosphere, making them very attractive from alife-cycle point of view.

carbon fibers and graphene—are extremely valuablecommercially, far more than amorphous carbon. Thisdevelopment has brought renewed attention to thefield, because it suggests that a technology based on
this process could simultaneously capture CO2 andproduce highly economically valuable materials.

A key aspect of these high-value products is thatthe economic value generated by producing themfrom CO2 could help spur additional privately funded
research and investment in CO2 capture and conversion
technologies. If so, the overall climate impact of theintroduction of CO2-based durable carbon materials
will be larger than their primary emissions mitigation.

While encouraging, these results have only beenreported by a small number of research groups (insome cases, a single group) and have only achieveda total production scale of less than a kilogram ofmaterial. They therefore need to be considered withcaution, and the main results must be reproducedby other researchers, both to validate them and to
broaden the understanding of the underlying methods
across the research community. The methods are welldescribed in the published literature, so replicatingthem should be relatively straightforward.

State of the technology
Research beginning in the 1960s revealed that it waspossible to deposit solid carbon using electrolysis
in molten salts that contain lithium and carbonate
ions (CO32-).3 The deposited carbon was either poorly
characterized or found to be mostly amorphous, andtherefore not particularly interesting economicallyor technologically. More recently, researchers began
to consider the possibility of using this process tocapture and convert CO2. The main electrochemical
process first reduces carbonate ions in the melt,
which then produces both solid carbon and oxideions. These oxide ions next react with CO2 to form
more carbonate ions, resulting in a net conversion
of CO2 to solid carbon.4 While the precise chemistry
remains imperfectly understood, a growing numberof studies have demonstrated the process (see Table
4.1). These experiments typically use molten lithium
carbonate (Li2CO3) or Li-Na-K carbonate mixtures as anelectrolyte, with temperatures in the range of
500-700 °C. The electrolyte is not consumed in
the reaction; instead, CO2 from the air (generally
unpressurized) is consumed, and solid carbon isdeposited on one electrode. In parallel to the workwith molten carbonates, researchers have also
explored electrolysis using molten salts such as CaCl2,
NaCl, and KCl, or combinations of carbonates andmolten salts, at similar temperatures.
More recently, researchers have improved theirability to characterize the deposited carbon andbegun to modify the process conditions to be able toproduce complex, nanostructured carbon materials.
These materials—particularly carbon nanotubes,

30

Table 4.1. Representative reported results of durable
carbon materials produced from CO2.
Representative studies
Licht (2016)5; Wu (2016)6;
Johnson (2017)7
Douglas (2017)8
Yin (2013)9
Le Van (2009)10
Tang (2013)11
Hu (2016)12
Kamali (2017)13
Hu (2017)14
Novoselova (2007)15

Products reported
Carbon nanotubes,
carbon nanofibers
Carbon nanotubes
Carbon powder
Carbon powder
Carbon powder, carbon
nanosheets
Graphene
Nano-diamonds
Carbon nanotubes
Carbon nanotubes,
carbon nanofibers

There is currently very limited effort to commercialize
this process; one early-stage U.S.-based company
is using molten carbonate electrolysis to produce
graphite.16
Beyond the need for replicating and validating theseresults, the other important research pathways
include:■■ Production quality: Improving the understandingof the process conditions for forming various typesof carbon materials, with a particular focus oncontrolled morphologies of carbon nanotubes, isessential. This is an active area of research, andNovember 2017

includes both increasing the yield of valuable
materials and controlling their uniformity.17■■ Alternatives to lithium: Investigating alternative
carbonate electrolytes and mixtures will be needed.
Much of the current research has focused onlithium carbonate or the ternary mixture Li-K-Na
carbonate.18 Lithium carbonate is in high demand
globally by lithium battery manufacturers, anddoubled in price from 2016 to 2017.19 The price may
continue to increase as the demand for lithium ion
batteries grows. Minimizing the necessary amountof lithium carbonate for electrolytic carbon material
production will likely be important for controlling
costs. In the long term, global production of lithium
carbonate should respond to rising demand andprices should stabilize, meaning that these cost
concerns may eventually fade.
■■ Production scale-up: Scaling production above

kilogram quantities is required, including developing
pilot-scale electrolysis facilities that can demonstrate
higher material throughput. This will take substantial
applied engineering research, including developing
technology for high-temperature electrolysis at scaleand developing concepts for how to enhance theproduction cycle (for example, creating continuous
production instead of batch production). This kind of
R&D is often difficult for policy makers and sponsors
to support, and may need targeted policy support. It
is important to note that there are strong technicalsynergies with molten carbonate fuel cells, which

are commercialized and operate at multi-megawatt
scale20 (see Box 4.2).
■■ LCA-guided R&D: As discussed below, a full life

cycle analysis is not yet possible, given the earlystage of the technology. However, basic insights
are possible, such as identifying the most likely
sources of life cycle emissions in the processes
being researched. This can be used to guide themost important directions for research.21 However,research groups that are concerned with achieving
basic technical results are often not equipped or
funded to also conduct LCAs, even at a basic level,so funding agencies should explicitly include support
for this, or work to connect research groups with
LCA researchers who can provide the necessary
expertise.

Market and utilization considerations
If these research challenges can be met, producing
durable carbon materials will become particularlyinteresting from a CO2U point of view, for several
reasons.
First, the (very) high value of these materials,
particularly carbon nanotubes, creates a powerful
economic motivation for the private sector to develop
and deploy the technology, once it reaches a certain
stage of technological maturity in the laboratory. Thisis very different from lower-value CO2-based products
such as cement and some industrial chemicals,
whose low market value implies that long-term policy

BOX 4.2 Molten Carbonate Fuel Cells
Molten carbonate fuel cells (MCFC) are stationary power systems that convert a variety of fuels (primarily
natural gas) into electricity and heat. They consist of a carbonate-based electrolyte(usually a mixture of lithium, potassium and/or sodium carbonate) and nickelbased electrodes, and operate at approximately 650° C. MCFCs are currently
being piloted for carbon capture at coal-fired power plants, because theyrequire CO2 for operation and may be able to significantly reduce the costsof capturing and concentrating CO2 compared to conventional amine-based
processes.22 MCFCs are also used in cogeneration applications, and eventri-generation (production of power, heat, and hydrogen).23 Operating MCFCs
in “reverse” mode as an electrolysis cell is an active area of research.24

November 201731

support (such as a carbon price) will be neededto drive deployment well after the technology ismature. This means that although public funding for
R&D is necessary at this early stage of the research,
longer-term public funding will not likely be necessary.
Therefore, public investments in early-stage R&D
to develop CO2-based durable carbon materials
production are likely to have high payoffs, without
creating a need for long-term policy support.
Second, these materials are very long-lived, and don’t
return CO2 to the atmosphere quickly. This is in stark
contrast to CO2-based fuels and chemicals, many ofwhich are burned or otherwise processed within days
or weeks, releasing their stored carbon dioxide. In fact,
carbon fiber composites in particular are so durable
that they don’t break down in landfills, a fact that hascaused concern about solid-waste accumulation andled to support for R&D on recovery and recycling.25
While carbon fiber recycling technology will probably
be developed, the rapid growth in demand forcarbon fiber means that recycling alone will neverprovide sufficient supply. An analogous case can bemade for synthetic diamonds, where production
breakthroughs could increase the use of diamonds
in other applications (e.g. diamond-based quantum
computing).26 Ultimately, a process that locks
atmospheric CO2 into an immutable solid carbon form
that is landfilled is likely to compare favorably withany short-lived carbon product from a climate point ofview.
Third, many of the applications of carbon materials,
particularly carbon nanotubes, carbon fiber, andgraphene, have ancillary emissions reductions
benefits. Some examples of this include improving
aircraft and vehicle fuel efficiency through lightweighting with carbon fiber, enhancing wind turbine
blade performance with carbon fiber27 and graphene,28
enabling lightweight hydrogen and natural gas storage
tanks for vehicles with carbon fiber, improving vehicle
fuel efficiency using polycarbonate windows, andimproving the capacity of lithium ion batteries withgraphene electrodes29 (which could accelerate theadoption of electric vehicles). This is in stark contrast
with the case of CO2 utilization for enhanced oil
recovery (EOR), where the storage of captured CO2 isoffset by emissions from the produced oil.
If carbon materials could be manufactured at lower
cost than with conventional technology, they could
32

penetrate other important markets where they are notcurrently competitive, including electronics, sensors
and optics. There may be an opportunity to develop
carbon-fiber-based shipping containers, which would
be significantly lighter than aluminum, resulting in fuelsavings, and possibly ancillary benefits such as more
rapid security inspections.30 Carbon fiber composites
re entering architectural use as structural elements(often replacing steel rebar) and as seismic retrofits
for reinforced concrete.31,32 Lower-cost carbon fiber
could compete more extensively with steel in concrete
reinforcement applications, and could also prolong thelife of concrete structures through carbon-fiber fabricwrapping and lightweight structural reinforcements.
Finally, there has been initial research on the use ofcarbon fiber additives to reinforce asphalt (improving
lifetime and reducing the need for repaving) and to
make asphalt electrically conductive as a runway
de-icing strategy.33
Within this broad range of materials, the largest
market potential, both in terms of value and total
mass flow, is carbon fiber. Average costs of carbon
fiber vary by application (reflecting different quality)
and range from $28/kg to $116/kg, while the overallmarket is growing at 12.5% CAGR.34 A key issue inthe carbon fiber market is the fact that there is asmall number of major manufacturers globally, all ofwhom use proprietary and non-standard production
processes. This, combined with the fact that there
are significant new non-conventional carbon fiber
production methods being introduced to the market(notably lignin precursors)35 means that any CO2-basedcarbon fiber materials will face complex and potentiallyunclear product specifications and standards inorder to enter the market. While resolving thiscomplication is outside the scope of CO2U policy (andthis roadmap), the situation should be monitored as
CO2-based carbon material production moves toward
the applied research stage.
As with cements, aggregates, chemicals, and fuels,
long-lived CO2-based materials must achieve certain
performance standards and receive approval andcertification to enter the market. Because theapproaches discussed here are relatively exotic, CO2based materials face additional hurdles in permitting
and standardization. These hurdles can, in part, beaddressed by crafting performance-based regulations
and standards—something already encouraged by
November 2017

most standardization bodies, but still uncommon inpractice. Nonetheless, it is likely that standards-settingorganizations and procurement organizations are
currently mostly unfamiliar with the idea of CO2-based
substitute materials, their manufacturing approaches,
and issues of quality and defect occurrence. Therefore,
there is a potentially important role from a policy
perspective in jump-starting the education andevaluation process of these technologies within key
organizations in order to avoid regulatory or statutory
delays in new CO2-based products entering markets.
Key organizations for this include the International
Organization for Standardization (ISO), ASTM
International, and the International ElectrotechnicalCommission (IEC).

Life cycle analysis considerations
Life cycle analysis (LCA) of the very early-stage CO2based carbon materials technologies described hereis probably premature. However, there are several
issues that will clearly impact any future LCA when
the technology is more advanced. The first is theenergy source used in the conversion process, whichis relevant for some processes (e.g. high-temperatureelectrolysis or diamond crystallization). The carbon
intensity of the electricity used will strongly impact
the overall LCA; at industrial scale this may simply
be determined by the local power grid, but could
potentially directly incorporate solar or otherrenewable electricity sources.36
A second issue will be the thermal efficiency of the(likely high-temperature) process, including heatrecovery. As a point of comparison, in commercial
aluminum smelting, roughly half the input energy
is lost as waste heat, with significant unexploited
opportunities to better capture it.37 Heat management
will clearly be determined in part by processengineering, and should be included at an early stage
in the design considerations. Notably, in the HallHéroult process, produced aluminum is periodicallysiphoned from the cell in liquid form, meaning thatcells can operate continuously without having to
be cooled and re-heated. It may be necessary todevelop some analogous method for recovering
produced carbon materials continuously rather thantemperature-cycling the cells (thereby dramatically
improving both efficiency and productivity).

November 2017

The third issue that can be anticipated at this stage isthe emissions footprint of any consumed electrodeor electrolyte materials, or other reactants. Until
the process details can be developed and better
understood through further early-stage research, it isdifficult to make any predictions about this. The best
approach would be to include ongoing attention to theemissions consequences of these materials/reactantsin the core research stream (also known as LCA-guided
design).
Any LCA of CO2-based carbon materials production
should be compared with conventional production
routes, and alternative production methods underconsideration. This should specifically include a
comparison with recovery and recycling of carbon fiber
composites (where the embedded energy savings may
be quite large) and carbon fiber production methods
using non-petroleum-based precursor feedstock.38

Roadmap considerations
Given the very early-stage nature of this technology,
it is not possible to develop a roadmap that includes
a detailed industrial scale-up strategy. But within theconstraints of the current technology maturity, there
are clear milestones for advancing the core technology(including manufacturing), the understanding ofoverall emissions, and market acceptance of CO2-basedcarbon materials through standards and certification.
Figure 4.1 lays out these milestones and their relative
sequence.

Key findings and recommendations
Findings:■■ Early-stage research has shown that there arepathways for converting CO2 directly into a range of
durable carbon materials.
■■ Some of these materials, particularly carbon fiber,

have large and valuable potential markets.
■■ The long-lived nature of these products, and theirancillary emissions benefits (such as improving fuelefficiency through vehicle light-weighting) imply thatthe life-cycle emissions impacts will be favorable.
■■ Currently, there is a need for increased early-stage

R&D support to replicate results and improve thecore technology.

33

Reproduce
primary technicalresults

Demonstrateconsistent productionof high-quality
materials

Long-term(4-15 years)

Fully commercialized(5-20 years)

Design pilot-scale
production cell(leverage MCFC
technology)

Design full-scale
production cell

Demonstratekg-scale yieldsof high-quality
materials

Demonstratehigh-throughput
production of highquality materials

Confirm LCA underfull production
conditions

EMISSIONS

Improve theoreticalunderstandingof process
chemistry

Medium-term(2-8 years)

Conduct initial LCA
with primarysensitivities

Conduct improved
LCA withestablished processparameters

Confirm LCA
under pilot-scale
production
conditions

STANDARDSTECHNOLOGY

Near-term(1-3 years)

Initiate discussion
with standards &certification
bodiesBegin process
to certify
CO2U-produced
carbon materials

Certify CO2Uproduced carbon
materials forbroad use

Figure 4.1. Conceptual roadmap for accelerating the development and commercialization of CO2-based durable
carbon materials.
■■ Applied research support for scaling up production

from the laboratory scale will be necessary in themedium term. This should be accompanied by life
cycle emissions analyses that progressively refine
their estimates as the technology matures.

and materials. R&D programs should incorporate life
cycle considerations into planning to maximize thelikely climate benefits of the resulting technologies.
■■ Governments and companies should engage earlywith standards-setting organizations in order to avoid
delays in market introduction of these products.
The key focus should be on education, process
discussions, and regulatory concerns.

■■ There are technology synergies with molten

carbonate fuel cells, and that research community
should be encouraged to partner with research
efforts on CO2-based durable carbon materials.
It is too early to consider market-pull policies
such as subsidies or purchase mandates for thesetechnologies. Also, the fact that many of these carbon
materials would enter markets in which there isalready significant demand means that market-pullpolicies may not be necessary at all in the future.

1

S. Das et al, “Global Carbon Fiber Composites Supply
Chain Competitiveness Analysis”, Clean Energy
Manufacturing Analysis Center, ORNL/SR-2016/100 |NREL/TP-6A50-66071 (2016).

2

Douglas and Pint, “Review – Electrochemical Growthof Carbon Nanotubes and Graphene from Ambient
Carbon Dioxide: Synergies with Conventional Gas-Phase
Growth Mechanisms”, ECS J. S. S. Sci. & Tech. (2017).

3

Ingram et al, “The electrolytic deposition of carbon
from fused carbonates”, Electrochimica Acta (1966).

4

Ijije and Chen, “Electrochemical manufacturing of
nanocarbons from carbon dioxide in molten alkali metal
carbonate salts: roles of alkali metal cations”, Advancesin Manufacturing (2016).

Recommendations:■■ Decision-makers should increase investment inconversion of CO2 to long-lived, high-value carbonbased products, and support long-term, stable
research programs to improve the chances ofsuccessful outcomes.
■■ New LCA data and methods are needed to better
understand the climate benefits of these processes
34

November 2017

Licht et al, “Carbon Nanotubes Produced from Ambient
Carbon Dioxide for Environmentally Sustainable
Lithium-Ion and Sodium-Ion Battery Anodes”, ACS
Central Science (2016).

5

Wu et al, “One-pot synthesis of nanostructured carbon
materials from carbon dioxide via electrolysis in molten
carbonate salts”, Carbon (2016).

6

Johnson et al, “Carbon nanotube wools made directlyfrom CO2 by molten electrolysis: Value driven pathways
to carbon dioxide greenhouse gas mitigation”, Materials
Today Energy (2017).

7

Douglas et al, “Sustainable Capture and Conversion
of Carbon Dioxide into Valuable Multiwalled Carbon
Nanotubes Using Metal Scrap Materials”, ACS Sus.
Chem. & Eng. (2017).

8

Yin et al, “Capture and electrochemical conversion of
CO2 to value-added carbon and oxygen by molten salt
electrolysis”, E&E Science (2013).

9

10

11

12

Le Van et al, “Electrochemical formation of carbon
nano-powders with various porosities in molten alkali
carbonates”, Electrochimica Acta (2009).
Tang et al, “Effects of applied voltage and temperatureon the electrochemical production of carbon powders
from CO2 in molten salt with an inert anode”,
Electrochimica Acta (2013).
Hu et al, “Direct Conversion of Greenhouse Gas
CO2 into Graphene via Molten Salts Electrolysis”,
ChemSusChem (2016).

13

Kamali, “Nanocatalytic conversion of CO2 into
nanodiamonds”, Carbon (2017).

14

Hu et al, “Electrochemical deposition of carbon
nanotubes from CO2 in CaCl2-NaCl-based melts”, J.
Mat. Chem. A (2017).

15

16

17

Novoselova et al, “Electrolytic production of carbon
nano-tubes in chloride-oxide melts under carbon
dioxide pressure”, Hydrogen Materials Science andChemistry of Carbon Nanomaterials (2007).
See “Advanced Manufacturing for Low-cost Highperformance graphite”, US Department of Energy
website; “SBIR Phase I: Supercritical Carbon Dioxide
Assisted Purification of Electrolytically Synthesized
Graphite”, SBIR website.
Ren et al, “Transformation of the greenhouse gas CO2
by molten electrolysis into a wide controlled selectionof carbon nanotubes”, Journal of CO2 Utilization (2017).

November 201718

Ijijie et al, “Carbon electrodeposition in molten salts:
electrode reactions and applications”, RSC Advances(2014).

19

McCormick, “Lithium contract prices for 2017 double
2016 levels”, Industrial Minerals (2016).

20

McPhail et al, “International status of molten carbonate
fuel cells technology”, IEA Energy Technology Network(2015).

21

Holman et al, “Using Life Cycle Assessment to Guide
Catalysis Research”, Ind. Eng. Chem. Res. (2009).

22“Fuel Cell Energy and Exxon Mobil Announce Location
for Fuel Cell Carbon Capture Pilot Plant”, Fuel Cell
Energy press release (2016).

23

Rinaldi et al, “Study of CO2 recovery in a carbonate fuelcell tri-generation plant”, J. Power Sources (2015).

24

Hu et al, “Performance and Durability of the Molten
Carbonate Electrolysis Cell and the Reversible Molten
Carbonate Fuel Cell”, J. Phys. Chem. C (2016).

25

Barnes, “Recycled carbon fiber: Its time has come”,
Composites World (2016).

26

Nemoto et al, “Photonic Architecture for Scaleable
Quantum Information Processing in Diamond”, Phys.
Rev. X (2014).

27“Wind energy blowing life into global carbon fiberindustry”, Windpower Engineering & Development(2013).

28“Graphene-reinforced composites may lead to longer,
lighter blades and more”, Windpower Engineering &Development (2014).

29

Zhu et al, “The application of graphene in lithium ion
battery electrode materials”, Springerplus (2014).

30“Composites could revolutionize shipping containers”,
Plastics Today (2014).

31“Carbon fiber grids replace steel as innovative concrete
reinforcement”, JEC Group (2013).

32

Sara Black, “Carbon fiber: Key to cost-conscious rehab”,
High-Performance Composites (2014).

33“Fiber Additives in Asphalt Mix”, Transportation
Research Board (2015).

34

Das, op. cit.

35

Sara Black, “Alternative precursor R&D: Lignin in thelightweighting limelight”, Composites World (2016).

35

36

Licht et al, “A New Solar Carbon Capture Process:Solar Thermal Electrochemical Photo (STEP) Carbon
Capture”, J. Phys. Chem. Lett. (2010).

37

Nowicki and Gosselin, “An Overview of Opportunities
for Waste Heat Recovery and Thermal Integration in
the Primary Aluminum Industry”, JOM (2012).

38

Mainka et al, “Lignin – an alternative precursor forsustainable and cost-effective automotive carbon
fiber”, J. Mat. Res. Tech. (2015)

36

November 2017

Chapter 5:Life Cycle
Assessment
Estimating the emissions reduction
benefit
Most of the recent interest in CO2 utilization has been
driven by the goal of stabilizing greenhouse gas (GHG)
concentrations in the atmosphere (Chapter 1). As thisroadmap highlights, CO2-based products vary widelyin the amount of CO2 they incorporate, the energy
intensity of their production, the markets in which
they compete, and their lifetime and ultimate disposal.
Determining the climate benefit of a CO2-based
product depends on these and other factors.
Consider the process of converting CO2 to methanol,using hydrogen generated from water electrolysis
as an example. The climate impacts of that process
will depend on several factors: the emissions
associated with capturing and transporting theCO2 used as a feedstock, generating the electricity
used in production, and the emissions avoided bydisplacing manufacture of methanol made fromfossil fuels, amongst others. According to one recent
study, displacement of fossil fuel-based methanol isa particularly crucial factor.1 Thus, looking at the GHG
emissions associated with only the production of CO2based methanol presents a partial—and potentiallymisleading—picture of its emissions impact.
Assessing the capacity of the myriad CO2-based
products and conversion pathways to contributeto stabilization of GHG concentrations requires

November 2017

systems thinking. This includes an understanding of
the multiple steps involved in product manufacture;
flows of energy, materials, and waste between them;and, the sources of raw materials and the final usesof products. Life cycle assessment is a structured
method of assessing the environmental sustainabilityof a system. Although assessing the emissions
reduction potential of CO2 utilization (CO2U) poses
methodological challenges, life cycle assessment iswell-suited to the task.

What is life cycle assessment and why
does it matter?
Life cycle assessment (LCA) quantifies inputs (including
materials and energy) and outputs (including wastes)
over the life cycle of a process or product—ideallyfrom “cradle-to-grave”—and then assesses theirimpacts to human health and the environment. The
general principles, framework and requirements for
LCA are widely accepted and have been codified in
ISO standards,2 with additional guidance provided byorganizations such as the European Commission3 andU.S. Environmental Protection Agency.4 Many energy
and environmental policies have been developedwith life cycle thinking in mind; indeed, a growing
number of laws and regulations require the use of LCA.
Notable examples include the European Union’s Waste
Framework Directive,5 Fuel Quality Directive (FQD),6and Renewable Energy Directive (RED).7 Examples in
the United States include the Renewable Fuel Standard(RFS); and the California Low Carbon Fuel Standard(LCFS).8
The ISO LCA standards provide for a great deal offlexibility in their application and have been applied
to a wide range of processes and products. An LCA
compliant with the ISO Standard will have a clearly37

defined goal and scope, inventory analysis, impact
assessment and interpretation of the results. The
goal and scope will include a statement of theintended application for the results, the rationale
for undertaking the work, a clear delineation of theboundaries of the system, and the “functional unit” forthe analysis (e.g. a MWh of electricity, ton of formic
acid, or kilometer traveled). Whether the boundaries
of an LCA truly encompass the entire life cycle—from
the production of raw materials through to disposalof the products—depends on the goals and intended
application for the LCA. For example, where theobjective is to compare a CO2-based product with an
identical product on the market (e.g. methanol), theuse and final disposal of the products are the sameand consideration of the entire lifecycle may not beneeded.9
During the inventory analysis, the inputs and outputs
are estimated for each part of the process in question
and then summed to provide system-level results. The
results of the inventory analysis are mass, volumetricor energy flows normalized to the functional unit of
the LCA (e.g. kg of CO2, m3 of water or MJ of oil perunit product). These inventory analysis results are
sometimes presented as the end results, in which casethe study should be properly referred to as a life cycle
inventory (LCI). In the life cycle impact assessment(LCIA), the inventory analysis results are thentranslated into terms that allow the impacts of theseflows to be assessed. For example, the climate change
impacts of GHG emissions, such as CO2, methane andnitrous oxide can be converted to CO2-equivalent units(e.g. tCO2-eq) using global warming potential (GWP)
or global temperature change potential (GTP).10 Other
frequently considered impact categories include ozone
depletion, acidification, eutrophication, fossil fueldepletion and human health.
For the results of the impact assessment to be
useful, they should also be summarized in a waythat is suitable, considering the goals and scope of
the LCA and any limitations highlighted. While not arequirement of the ISO Standard, it is a best practice toexplore the results of uncertainty and variability in data
and models on the results.11 Ignorance of the potential
ranges of results (and their distribution) can lead topoor decisions, particularly in product-comparison
studies. The inadequate treatment of uncertainty in

38

LCA of biofuels and LCFS-like policies has been thefocus of much criticism.12
LCA can be undertaken for a wide variety of reasons,such as to identify “hotspots” and opportunities
for improvement through R&D or design changes,
inform purchasing decisions through product footprinting, identify strategic opportunities to improvesustainability in product portfolios (e.g. reducing
the wash cycle temperature for detergents), guide
public R&D investment, and inform policy making.13
Traditional environmental LCA, however, isn’t a
substitute for cost-benefit analysis, risk assessment
or environmental impact assessment and—like allof these tools—provides information that must be
carefully weighed by decision makers.

Developing consistent LCAs for CO2based products
LCA of CO2-based products presents a number ofmethodological challenges, many of which werehighlighted in the first version of this roadmap andother reviews.14 The following section recaps thesechallenges, along with suggested solutions to addressthem.
The first challenge is treatment of the CO2 feedstock.
Whether CO2 should be treated as a “waste” or a“commodity” is a question that has been debated in
the context of CCS.15 However, where captured CO2 isthe feedstock for a CO2-based product, it should betreated like any other feedstock.16 Thus, the source of
the CO2 and the environmental impact of capturing
the CO2 matters. For example, von der Assen et al.17
estimate that, relative to a case in which CO2 wasemitted, capturing CO2 from an existing industrial
facility in the EU would reduce emissions by between
0.42 tCO2-eq and 0.99 tCO2-eq per ton of CO2 supplied,depending on the type and location of the facility.18
The environmental impact of CO2 supply should be
addressed by including the CO2 capture process within
the boundaries of the LCA, and where the sourceof CO2 is not known, a range of sources should beconsidered.
The multiple-product nature of CO2U systems can alsopose a challenge. This may occur where CO2 capture
cannot be separated from production of a “primary
product” (e.g. steel) due to the goals and scope of theNovember 2017

study. In such a case, the system will have multiple
products (e.g. steel and methanol). Even where
CO2 capture can be separated analytically, the CO2
utilization process may also result in multiple products,
for example, where CO2 is converted to syncrude usinga Fischer-Tropsch process. In such cases, generating
accurate LCA results for the product of interest (e.g.
gasoline) requires the lifecycle inventory to either be
allocated across all the products from the system or
the boundaries of the system expanded to include all
the products.
For multiple-product systems, the ISO Standard
recommends system expansion over allocation,19 asdifferent approaches to allocation can result in very
different results for the same system. When facedwith a comparable problem in the context for a study
on CO2 storage through enhanced oil recovery (EOR),
Cooney et al. expanded the boundaries of theirsystem to include the electricity generation lifecycle
and credited the by-product CO2 (from electricity
generation) with the avoided burden of producing
electricity using a range of alternative approaches.20
The clear benefit of the avoided burden approachis that the functional unit is simplified to a single
product, which usually makes the results more easily
comparable and is generally a sensible approach for
CO2U.21
Another significant challenge for LCA of CO2-based
products is the assessment of consequential effects.
CO2-based products may displace other products inthe market and, if so, that displacement will have anenvironmental impact that should be attributed to theCO2-based product. However, determining whether
and which other products are displaced will dependon elasticities of demand and other factors for whichdata may be limited. Determining the environmental
impact of the displaced product may not be easy or
straightforward either. Additionally, at least in theory,
this would require results from a consistent LCA for the
displaced product.
For globally traded products, such as the CO2-based
products considered in this roadmap, estimating thechange in consumption (and hence emissions) requires
an economic model. Given the uncertainties inherent
in such models, estimation also demands careful
treatment of uncertainty. Consequential effects canbe significant, as illustrated in the case of biofuels22
and enhanced oil recovery (EOR).23 The need to assess
November 2017

these consequential effects is an opportunity forthe energy systems modeling and LCA communities
to work more closely together. Of course, LCA canprovide useful insights even without more complex
consequential analysis.
A fourth challenge for LCA for CO2-based products(shared with CCS24 and biofuels)25 is the timedependence of the impact of GHG emissions (orremovals). This affects the value associated withtemporary removal of CO2 from the biosphere. The
most commonly used measure of climate change
impact is the 100-year GWP (GWP100): the cumulative
impact of an instantaneous emission of a given GHG
on the earth’s energy balance over a century, relative
to that of CO2.26 In conventional LCA, a constant
GWP is used to convert inventory to climate impacts,
regardless of when the emission occurs, and ignores
the benefit of delaying emissions through temporarystorage, implying a temporal mismatch between the
period over which the LCA is being performed and thatof the impacts assessed. While a 100-year time horizon
is commonly used, it is rarely acknowledged that the
choice of the time horizon (both for GWP and for theLCA) implies a value judgement about the relative
importance of impacts over time.27
In principle, the climate change impact assessment
method chosen for LCA should reflect the factthat products in which CO2 is stored longer have asmaller climate impact (i.e. a larger benefit) than for
short-lived products where CO2 is returned promptly.28
There are multiple different approaches to address thischallenge, but consensus has not yet emerged on themost generally appropriate method, and this is an area
where guidelines for CO2U could help.29
Fifth, many CO2U processes are at very early stagesof technological development. Information about
the performance of a CO2-based product and its
production process may be limited; what information
is available may be difficult to extrapolate tocommercial scales, and future performance may behighly uncertain.30 These factors all make comparisonswith more established technologies more difficult.
Thus, it is important for LCA to be integrated into
the R&D process and for prospective assessments
to be carried out as the technology evolves, for the
results of LCA to feed back into the R&D process andinfluence the direction of R&D, for the limitations ofsuch LCA studies to be clearly defined, and, for suitable39

sensitivity analysis to be performed that illustrates thefull range of possible outcomes.
Finally, while much of this discussion has focused on
the climate change impacts of CO2-based products,
other impacts can make or break the commercial
success of processes. For example, the conventionalroute to produce dimethyl carbonate requires
phosgene (COCl2), a highly dangerous substance thatwas used as a chemical weapon in World War I. In
contrast, the CO2-based route avoids phosgene—moreover, dimethyl carbonate can serve as a substitutefor phosgene in synthesis processes.31 Similarly, theuse of CO2 in polyurethane production has beenshown to reduce a wide range of impacts beyond
climate.32 When focusing on climate change impacts,
it is important not to lose sight of other environmental
impacts.

Examples of LCA for CO2-based products
In a 2015 critical review of CCUS LCA studies, CuéllarFranca and Azapagic identified 16 peer-reviewed LCA
studies of CO2 utilization systems.33 Three-quarters ofthese studies dealt with EOR or fuel production fromalgae (which are outside the scope of this roadmap),leaving only four studies of systems that generated a
CO2-based product.34 Only one of those four studies
explicitly considered the CO2-based product as a
product, rather than as a waste from CO2 capturein electricity generation. This illustrates both thecomplexity of executing LCAs for CO2-based products
and the novelty of the topic.
A handful of additional peer-reviewed LCA studies havebeen published (largely subsequent to the writing of
the 2015 review) that address:■■ Polyurethane: The climate change (GWP) andfossil-fuel depletion impacts of using CO2 directly inpolyol production for polyurethane—and indirectly,
as a feedstock for other chemicals (e.g. methanol,
isocyanates) used to make polyurethane—wasinvestigated by von der Assen et al.35 Their studies
conclude that incorporating CO2 into polyols reduces
the GWP of their production relative to conventional,
fossil-based processes. It also concludes thatusing the maximum amount of CO2 possible in thepolyurethane production chain is not the optimal
way to reduce GWP.

40■■ Dimethyl ether (DME): The environmental

performance of direct DME synthesis from syngas
in a refinery complex (where the syngas is produced
from dry reforming of methane36 and CO2 captured
from hydrogen production) was investigated by
Schakel et al.37 Production of CO2-based DME
has a smaller GWP than DME produced from a
conventional route (i.e. dehydration of methanol)and the CO2 emitted (rather than captured).
However, it has substantially poorer environmental
performance in some other areas, particularly withregard to water impacts, resulting from increased
electricity demand and rare-earth metal demands
for catalyst production. They also found that the
GWP of DME produced via the conventional routeand the CO2 captured and stored (rather than beingused) is much lower than the CO2-based DME.
■■ Carbon monoxide, formic acid, methanol andmethane: The climate change (GWP) and fossilfuel depletion impacts of these chemicals has been
evaluated in three, partially overlapping studies.
Two of the studies evaluate the emissions reduction
potential and economics of direct thermocatalytic
methanol production and electrochemical formic
acid production; however, only one, performed for
the French Environment and Energy Management(ADEME), considers the full product lifecycle,
including CO2 supply.38 This study concluded that
substitution of both CO2-based products for theirfossil-based equivalent would result in emissions
reductions with the use of low-carbon French
grid electricity—1.4 tCO2 avoided per ton of fossil
methanol displaced, and 2.75 tCO2 avoided per ton
of formic acid displaced. The third study evaluatedthermocatalytic production of all four products, withthe goal of identifying which product’s substitution
could result in the largest benefit and where alimited supply of low-carbon hydrogen would havethe largest impact. They find that only CO2-based
formic acid has a lower GWP than its conventional
fossil-based equivalent in the base case, but that
this conclusion is relatively robust to changes inhydrogen supply. At the other end of the spectrum,
they find that CO2-based methane produced with
CO2 captured from the air has GWP lower thanfossil methane—but only if wind electricity is used
to produce hydrogen via electrolysis across all
CO2-supply and process scenarios (i.e. electricity

November 2017

generated from solar PV doesn’t have a sufficiently
low GWP).
■■ Carbonate minerals: The energy efficiency and CO2
storage potential production of carbonate minerals
using a range of different aqueous carbonation
processes, using different alkalinity sources (natural
silicates, cement kiln dust, fly ash and steel slag) was
compared by Kirchofer et al.39 They considered theseprocesses as a means of CO2 storage (rather thana utilization option) and, thus did not consider theenvironmental burdens of CO2 capture. Nonetheless,they found that, on balance, these processes
resulted in an absolute emissions reduction (since
the CO2 is permanently bound in mineral form)
and that there is significant room to improve theenvironmental performance of mineralization
processes through optimization.
While these recent studies add to the knowledge
base for CO2-products, they also support some of thecriticisms of Cuéllar-Franca and Azapagic, such as theneed for consistency in functional units for different
CO2-based products and (as already mentioned)
inclusion of the CO2-supply process in study
scopes.40 In addition, given early stage of technology
development for most CO2-based production processes(and many CO2-capture processes), LCA studies should
better characterize the uncertainties in their results
and potential areas for improvement.

Findings and recommendations
Findings
LCA is an important tool to quantify the climate change
impacts of CO2-based products. It can also be used tofocus R&D in areas that could bring about the greatest
benefits. ISO standards and guidance exist for LCA
practitioners that, if followed, can improve the qualityof an LCA and improve the chances that the results will
be accurate and robust. However, there is a need torefine this guidance for CO2U applications.
Based on our review of LCA for CO2-based products,
we suggest that:■■ CO2 supply (i.e. capture and transport) should bewithin the scope of an LCA that aims to estimate theclimate change impacts of a CO2-based product;■■ Existing guidance (e.g. provided in ISO standards,
government agency guidance, and peer-reviewed
November 2017

literature) around LCA boundary expansion and, if
necessary, allocation should be followed (includingtransparent, justifiable choices for avoided burdens);■■ Where the LCA seeks to inform decisions that

could have impacts to the broader market (e.g.
government policy), the impacts of displacement ofother products should be considered in an LCA; and,■■ The CO2U and broader LCA communities agree upon
an approach to climate-impact assessment thatplaces an appropriate value on temporary storage of
CO2 in products.
In addition, while the current motivation for CO2-based
products means that climate impacts are typicallypresented first and foremost in LCA studies of thesesystems, other environmental impacts are importantand can be pivotal in decision-making. Provision of
product footprints affects the purchasing decisions of
informed consumers.
Peer-reviewed LCAs have been performed for very
few CO2-based products. From the few that have been
performed, several general conclusions can be drawn
for CO2-based products:■■ Maximizing CO2 use in the production chain does notnecessarily maximize avoided emissions;■■ The benefits of CO2 use can appear where one
doesn’t expect them – e.g. by reducing cement
consumption;■■ Benefits of CO2 use can be maximized by making CO2based products that substitute for fossil equivalentswith complex and energy intensive production
systems;■■ The carbon intensity of electricity (and hydrogen)supply is very important.
Additional studies are required that guide R&D
towards products and processes that are likely to havethe largest environmental benefit.

Recommendations
To support the goal of advancing the near-termcommercialization and long-term potential of CO2based products:■■ Research funding bodies should provide support

for additional studies of CO2-based products andproduction pathways with the aim of directing R&D.

41

■■ Consensus guidelines should be developed thatelaborate on the application of the existing ISO
standards and related guidance to LCA for CO2-based
products and production systems.
■■ LCA studies that aim to make comparative
statements about the emissions reduction benefitsof CO2-based products relative to others should,
ideally, present probabilistic uncertainly analysis that
captures the impact of different CO2-supply options(where these are not fixed by scope), electricity
supply mixes, and hydrogen (or mineral) supply
options. Where fully probabilistic treatments ofuncertainty are not practical, alternative sensitivity
analysis approaches should be used (e.g. bounding
analysis).
■■ The LCA and energy-modeling communities should
work together to better represent CO2 utilization
options in energy systems models and better
understand the boundary conditions for CO2
utilization processes in the future energy system—
particularly as a means of improving consequential
LCA for CO2-based products.
■■ The CO2 utilization community and the LCA
practitioners working with them should be cognizantof the lessons learnt from LCA of biofuels and CCS—
these systems share many of the same features.
1

André Sternberg, Christian M. Jens, and André Bardow,“Life Cycle Assessment of CO2-Based C1-Chemicals,”
Green Chemistry 19, no. 9 (May 8, 2017): 2244–59,
doi:10.1039/C6GC02852G.

2ISO, “Environmental Management — Life Cycle
Assessment — Principles and Framework”(International Standards Organization, July 1, 2006);
ISO, “Environmental Management — Life Cycle
Assessment — Requirements and Guidelines”(International Standards Organization, July 1, 2006).
JRC, “ILCD Handbook: General Guide for Life Cycle
Assessment - Detailed Guidance” (Luxembourg:
European Commission - Joint Research Center,
March 2010), http://eplca.jrc.ec.europa.eu/uploads/
ILCD-Handbook-General-guide-for-LCA-DETAILEDGUIDANCE-12March2010- ISBN-fin-v1.0-EN.pdf.

3

4

U.S. EPA, “Life Cycle Assessment: Principles andPractice” (Cincinnati, OH: U.S. Environmental Protection
Agency, National Risk Management ResearchLaboratory, May 2006).

42

5“DIRECTIVE 2008/98/EC OF THE EUROPEANPARLIAMENT AND OF THE COUNCIL of 19
November 2008 on Waste and Repealing
Certain Directives,” 2008/98/EC § (2008), http://
eur-lex.europa.eu/legal-content/EN/TXT/
HTML/?uri=CELEX:32008L0098&from=EN.

6“Directive 2009/30/EC of the European Parliament andof the Council of 23 April 2009 Amending Directive
98/70/EC as Regards the Specification of Petrol,
Diesel and Gas-Oil and Introducing a Mechanism to
Monitor and Reduce Greenhouse Gas Emissions andAmending Council Directive 1999/32/EC as Regards theSpecification of Fuel Used by Inland Waterway Vessels
and Repealing Directive 93/12/EEC,” 2009/30/EC §(2009), http://data.europa.eu/eli/dir/2009/30/oj.

7“Directive 2009/28/EC of the European Parliament andof the Council of 23 April 2009 on the Promotion of the
Use of Energy from Renewable Sources and Amending
and Subsequently Repealing Directives 2001/77/EC and2003/30/EC,” 2009/28/EC § (2009), Directive 2009/28/
EC of the European Parliament and of the Council of 23
April 2009 on the promotion of the use of energy fromrenewable sources and amending and subsequently
repealing Directives 2001/77/EC and 2003/30/EC..

8“Low Carbon Fuel Standard,” Title 17 California
Code of Regulations § 95480-95497 (2015),
https://govt.westlaw.com/calregs/Document/
IC4D9979005294A50AB577FEB54E745B5? view Type=
FullText&originationContext= documenttoc&transition
Type=CategoryPageItem&contextData= (sc.Default).

9

Niklas von der Assen et al., “Life Cycle Assessment of
CO2 Capture and Utilization: A Tutorial Review,” Chem.
Soc. Rev. 43, no. 23 (January 20, 2014): 7982–94,
doi:10.1039/C3CS60373C.

10

Gunnar Myhre et al., “Anthropogenic and Natural
Radiative Forcing,” in Climate Change 2013: The
Physical Science Basis. Contribution of Working
Group I to the Fifth Assessment Report of theIntergovernmental Panel on Climate Change, ed. T. F.
Stocker et al. (Cambridge, U.K.: Cambridge University
Press, 2013), http://www.climatechange2013.org/
images/report/WG1AR5_Chapter08_FINAL.pdf.

11JRC, “ILCD Handbook: General Guide for Life Cycle
Assessment - Detailed Guidance.”

12

Kimberley A. Mullins, W. Michael Griffin, and H. Scott
Matthews, “Policy Implications of Uncertainty in
Modeled Life-Cycle Greenhouse Gas Emissions ofNovember 2017

Biofuels,” Environmental Science & Technology 45, no.
1 (January 1, 2011): 132–38, doi:10.1021/es1024993;
Matt Kocoloski et al., “Addressing Uncertainty in
Life-Cycle Carbon Intensity in a National Low-Carbon
Fuel Standard,” Energy Policy 56 (May 2013): 41–50,
doi:10.1016/j.enpol.2012.08.012; Elliot W. Martin,
Mikhail V. Chester, and Sintana E. Vergara, “Attributionaland Consequential Life-Cycle Assessment in Biofuels:
A Review of Recent Literature in the Context of
System Boundaries,” Current Sustainable/Renewable
Energy Reports 2, no. 3 (September 1, 2015): 82–89,
doi:10.1007/s40518-015-0034-9.
13

Stefanie Hellweg and Llorenç Milà i Canals, “Emerging
Approaches, Challenges and Opportunities in Life Cycle
Assessment,” Science 344, no. 6188 (June 6, 2014):
1109–13, doi:10.1126/science.1248361.

14

Issam Dairanieh et al., “Carbon Dioxide Utilization(CO2U) – ICEF Roadmap 1.0” (Tokyo, Japan: ICEF
Innovation Roadmap Project, 2016), http://www.
icef-forum.org/platform/upload/CO2U_Roadmap_
ICEF2016.pdf; von der Assen et al., “Life Cycle
Assessment of CO2 Capture and Utilization”; Niklas
von der Assen, Johannes Jung, and André Bardow,“Life-Cycle Assessment of Carbon Dioxide Captureand Utilization: Avoiding the Pitfalls,” Energy &Environmental Science 6, no. 9 (2013): 2721,
doi:10.1039/c3ee41151f.

15

Philip M. Marston, “Bridging the Gap: An Analysis andComparison of Legal and Regulatory Frameworks for
CO2–EOR and CO2–CCS” (Canberra, Australia: Global
CCS Institute, 2013), http://decarboni.se/sites/default/
files/publications/118951/bridging-gap-analysiscomparisonlegal- regulatory-frameworks-eor-ccs.pdf.

16

von der Assen, Jung, and Bardow, “Life-Cycle
Assessment of Carbon Dioxide Capture and Utilization”;
von der Assen et al., “Life Cycle Assessment of CO2
Capture and Utilization.”

17

Niklas von der Assen et al., “Selecting CO2 Sources
for CO2 Utilization by Environmental-Merit-Order
Curves,” Environmental Science & Technology 50, no.
3 (February 2, 2016): 1093–1101, doi:10.1021/acs.
est.5b03474.

18

In this case, a CCS system that generated no GHG
emissions during its construction and operation would
result in an emissions reduction of 1 tCO2-eq per tCO2
captured. However, if the basis for comparison were
that, instead of being emitted, the captured CO2 wasNovember 2017

be stored in a saline aquifer the CO2 there would be no
climate benefit to using captured CO2 as a feedstock.
19

ISO, “Environmental Management — Life Cycle
Assessment — Requirements and Guidelines.”

20

Gregory Cooney et al., “Evaluating the Climate
Benefits of CO2-Enhanced Oil Recovery Using Life Cycle
Analysis,” Environmental Science & Technology 49,
no. 12 (June 16, 2015): 7491–7500, doi:10.1021/acs.
est.5b00700.

21

von der Assen et al., “Life Cycle Assessment of CO2
Capture and Utilization.”

22

Richard J. Plevin, Mark A. Delucchi, and Felix Creutzig,“Using Attributional Life Cycle Assessment to Estimate
Climate-Change Mitigation Benefits Misleads Policy
Makers,” Journal of Industrial Ecology 18, no. 1(February 1, 2014): 73–83, doi:10.1111/jiec.12074.

23

IEA, “Storing CO2 through Enhanced Oil Recovery”(Paris, France: International Energy Agency,2015), https://www.iea.org/publications/insights/
insightpublications/storing-co2-through-enhanced-oilrecovery.html.

24

H. Herzog, K Calderia, and J. Reilly, “An Issue of
Permanence: Assessing the Effectiveness of Temporary
Carbon Storage,” Climatic Change 59 (2003): 293–310;
Minh Ha-Duong and David W. Keith, “Carbon Storage:
The Economic Efficiency of Storing CO2 in Leaky
Reservoirs,” Clean Technologies and Environmental
Policy 5, no. 3–4 (2003): 181–89; Fei Teng and Daniel
Tondeur, “Efficiency of Carbon Storage with Leakage:
Physical and Economical Approaches,” Energy 32, no. 4(2007): 540–48.

25

Miguel Brandão et al., “Key Issues and Options inAccounting for Carbon Sequestration and Temporary
Storage in Life Cycle Assessment and Carbon
Footprinting,” The International Journal of Life
Cycle Assessment 18, no. 1 (June 2, 2012): 230–40,
doi:10.1007/s11367-012-0451-6.

26

Myhre et al., “Anthropogenic and Natural Radiative
Forcing.”

27

Ibid.

28

von der Assen, Jung, and Bardow, “Life-Cycle
Assessment of Carbon Dioxide Capture and Utilization.”

29

Brandão et al., “Key Issues and Options in Accounting
for Carbon Sequestration and Temporary Storage in Life
Cycle Assessment and Carbon Footprinting.”
43

30

Alexandra C. Hetherington et al., “Use of LCA as a
Development Tool within Early Research: Challenges
and Issues across Different Sectors,” The International
Journal of Life Cycle Assessment 19, no. 1 (January 1,2014): 130–43, doi:10.1007/s11367-013-0627-8; Ben
A. Wender et al., “Anticipatory Life-Cycle Assessmentfor Responsible Research and Innovation,” Journal of
Responsible Innovation 1, no. 2 (May 4, 2014): 200–
207, doi:10.1080/23299460.2014.920121.

31

Evan S. Beach, Zheng Cui, and Paul T. Anastas, “Green
Chemistry: A Design Framework for Sustainability,”
Energy & Environmental Science 2, no. 10 (2009):
1038–49, doi:10.1039/B904997P.

32

Niklas von der Assen and André Bardow, “Life Cycle
Assessment of Polyols for Polyurethane Production
Using CO2 as Feedstock: Insights from an Industrial
Case Study,” Green Chemistry 16, no. 6 (2014): 3272,
doi:10.1039/c4gc00513a.

33

34

Rosa M. Cuéllar-Franca and Adisa Azapagic, “Carbon
Capture, Storage and Utilisation Technologies: A
Critical Analysis and Comparison of Their Life Cycle
Environmental Impacts,” Journal of CO2 Utilization 9(March 2015): 82–102, doi:10.1016/j.jcou.2014.12.001.
Michele Aresta and Michele Galatola, “Life
Cycle Analysis Applied to the Assessment of theEnvironmental Impact of Alternative Synthetic
Processes. The Dimethylcarbonate Case: Part 1,”
Journal of Cleaner Production 7, no. 3 (March 1999):
181–93, doi:10.1016/S0959-6526(98)00074-2; Hsien
H. Khoo and Reginald B.H. Tan, “Life Cycle Evaluation of
CO2 Recovery and Mineral Sequestration Alternatives,”
Environmental Progress 25, no. 3 (October 1, 2006):
208–17, doi:10.1002/ep.10139; Hsien H. Khoo et al.,“Carbon Capture and Mineralization in Singapore:
Preliminary Environmental Impacts and Costs via
LCA,” Industrial & Engineering Chemistry Research
50, no. 19 (October 5, 2011): 11350–57, doi:10.1021/
ie200592h; Experience Nduagu, Joule Bergerson,
and Ron Zevenhoven, “Life Cycle Assessment of
CO2 Sequestration in Magnesium Silicate Rock44

– A Comparative Study,” Energy Conversion andManagement 55 (March 2012): 116–26, doi:10.1016/j.
enconman.2011.10.026.
35

von der Assen and Bardow, “Life Cycle Assessmentof Polyols for Polyurethane Production Using CO2 as
Feedstock”; Niklas von der Assen et al., “Environmental
Potential of Carbon Dioxide Utilization in the
Polyurethane Supply Chain,” Faraday Discussions 183,
no. 0 (2015): 291–307, doi:10.1039/C5FD00067J.

36

In dry reforming of methane, CO2 and methane are
combined at high temperature over nickel based
catalysts producing a roughly 1:1 mixture of hydrogenand syngas. Refer to Section 2.2 for additional detail on
uses of dry reforming in CO2-based processes.

37

Wouter Schakel et al., “Assessing the TechnoEnvironmental Performance of CO2 Utilization via Dry
Reforming of Methane for the Production of Dimethyl
Ether,” Journal of CO2 Utilization 16 (December 2016):
138–49, doi:10.1016/j.jcou.2016.06.005.

38

Guillaume Kerlero de Rosbo et al., “Valorisation
Chimique Du CO2: Etat Des Lieux – Quantification
Des Bénéfices Énergétiques et Environnementaux etÉvaluation Économique de Trois Voies Chimiques”(Angers, France: Agence de l’Environnement et de laMaîtrise de l’Energie, 2014), http://www.ademe.fr/
valorisation-chimique-co2-etat-lieux-quantificationbenefices-energetiques-environnementauxevaluationeconomique- trois-voies-chimiques; Mar
Pérez-Fortes and Evangelos Tzimas, “Techno-Economic
and Environmental Evaluation of CO2 Utilisation for Fuel
Production: Synthesis of Methanol and Formic Acid”(European Commission Joint Research Centre, 2016),
https://dx.doi.org/10.2790/981669.

39

Abby Kirchofer et al., “Impact of Alkalinity Sources on
the Life-Cycle Energy Efficiency of Mineral Carbonation
Technologies,” Energy & Environmental Science 5, no. 9(2012): 8631–41, doi:10.1039/C2EE22180B.

40

Cuéllar-Franca and Azapagic, “Carbon Capture, Storage
and Utilisation Technologies.”

November 2017

Chapter 6:

General R&D Needs
for CO2 Utilization
In addition to the detailed research and development(R&D) needs cited in each chapter, we have identified
a set of cross-cutting R&D needs that apply broadly to
CO2 utilization.

Analysis
The most immediate R&D need in this area is forbetter analytical tools to understand the benefits of
CO2 utilization. This is critical for governments andother actors who want to encourage this as a meansof emissions management. Today, there are few endto-end analyses of the emissions benefit of utilization
schemes. Moreover, there is no universally accepted
approach to evaluating the benefit of turning carbon
dioxide into products that are long-lived, but not
permanently removed from the atmosphere.
The experience in California with the Low Carbon
Fuel Standard (LCFS) demonstrates that onceclear metrics are put in place, it is feasible to drive
technology to better and better outcomes. The
average carbon intensity (CI) of alternative fuels
being utilized in California has fallen 21% since theimplementation of the LCFS program, in no small partdue to technological innovation in fuel production.1
For example, the CI of the best performing corn-based
ethanol pathways certified under the LCFS has fallen
over time and is now approaching 40% below thatof gasoline. A vitally important aspect of the successof the LCFS program is the standardized approach
to life cycle assessment, based on the GREET model,
allowing the CI of a wide range of alternative fuels to
be consistently estimated. While aspects of the LCFS
remain controversial and ways to improve it havebeen suggested,2 the LCFS experience demonstrates
that thoughtful and uniformly applied life cycle
assessment is important to both policy and technology
development.
Unfortunately, a consistent approach to LCA
doesn’t yet exist for the CO2 utilization schemes
described here. This is attributable to the facts that
CO2 utilization concepts are still relatively nascentNovember 2017(at least compared to biofuels), there is a relative
dearth of policy mechanisms that might drive theircommercial deployment, and there is still debate overmethodological issues (e.g. consequential effects,
valuation of temporary GHG removals, end-of-life
treatment). Issues that should be addressed as part ofdeveloping a consistent approach include:■■ Agreement over the appropriate goals and scope for

LCA for CO2U.
■■ Consistent sets of assumptions for the environmental
burden of CO2 supply that reflect the best estimatesfor current (and future) CO2 capture technologies.
■■ Consistent sets of assumptions for the environmental
burdens associated with energy inputs—electricity,in particular—and hydrogen.
■■ Agreement on assessing the impacts of temporary
CO2 storage in CO2-based products.
With such guidelines in use, more general comparisons
can be made between different CO2-based productoptions than can be made with the few focused
assessments that are available today.
In addition to guidelines that enable more focused
LCA, studies are needed of the path to deployment forthe processes discussed here. The use of CO2 based
products at gigaton scale will link energy and materials
production in a way that is seldom considered inexisting energy systems models and will ripple acrossthe economy. These waves will be magnified where
the uses of CO2-based materials enable the provisionof services in a different or more efficient way (e.g.
durable carbon materials). This is the domain oftechno-economic and systems analysis. Such analysis
will allow more specific roadmaps to be developed
based on sensible long-term goals, and key questions
to be answered. For example, are there obvious supply
chain or geographic resource choke-points that would
limit deployment? Which policy mechanisms make themost sense to drive deployment? Where might R&D
have the biggest payoffs?

Catalysis
Many of the most interesting utilization schemes
involve catalysis. Most CO2-to-product conversions
have high activation energies, small yields andadditional separation steps. The design of better
catalysts in general would greatly reduce the overall
practical energy requirements and capital costs,
45

making CO2 conversions much more efficient than
today. This remains a major need for CO2U.
There are four catalytic pathways for CO2U: thermal,
electrical, photolytic and biological (refer to Section 2.2).
■■ Thermal approaches are the most mature and, forsome processes, are commercial today at small
scales (e.g. for CO2-to-methanol). Many are hightemperature processes (above 500 °C), so lowertemperature catalysts require more focus. High
selectivity is also a specific challenge (e.g. with
Fischer-Tropsch conversion).
■■ Electrical pathways have emerged as an importantnew research focus, in part due to the increased
availability of low-cost renewable power. In addition
to the need for lower overvoltage and greater
selectivity, many electrical pathways today are slow,
so catalysts with improved kinetics are a special
need. Finally, new materials for both anodes andcathodes require development.
■■ Most photolytic pathways require substantial
research to improve cost, performance, yields andrates. Many candidate catalysts involve exotic andexpensive materials. Much of the current researchis at a very early stage, and it is unclear how todramatically improve performance without morebasic research (or how to functionalize thosecatalysts that show promise).
■■ Biological pathways often have very good kinetics
but low yields and restrictions in temperature,pressure and pH. Again, much of this R&D is at a very
early stage, and would benefit from use-inspired
basic R&D.
Today, the energy usage of those catalytic schemes isdominated by two energy penalties: one associatedwith high temperatures and the other with electrical
overvoltage. Reducing overvoltage and temperature
for catalysts is part of many research programs, andshould be strongly encouraged as a near-term focus,
given the maturity of thermal approaches and thenear-term promise of electrical ones. In many cases,
the simultaneous reduction of CO2 and disassociationof water may be achieved beneficially in a single
process. Methods to make efficient use of electricalenergy in processes like that are required.
Two scientific approaches could greatly enhance
and accelerate design of catalysts. The first iscomputational material design, in which large
46

supercomputers perform very large numbers ofsimultaneous calculations to find promising newmolecular configurations. Tens of thousands ofmaterials can be analyzed each week, providing
direction and design specifications for chemists tobuild and test the new materials. The second approachis high-throughput experimentation, which allows
investigators to simultaneously test hundreds ofcandidate materials with the assistance of robots, bigdata and parallel processing. Both approaches enhancethe effectiveness of searches for new CO2-conversion
catalysts, and should be more formally incorporated
into R&D programs.

Reactor design advances
The development of thermal, electrical, biologicaland photolytic catalysts represents the first stage ofdevelopment, and commonly focus on low levels oftechnical readiness (i.e. near the benchtop). Full-scale
application requires considerable attention to theintegrated systems (reactors) that will utilize thosecatalysts. Most products today that take advantage
of conventional conversion media, such as syngasto-methanol reformers, batch reactors, or reverse
fuel cells, are based on approaches developed 20-80
years ago. Often, these conventional approaches havesubstantial shortcomings associated with capital cost,industrial scale-up, and mass-manufacturing.
Technological advances from 3D printing, microfluidics,
genetic engineering and computational design makepossible reactors and processes which are radicallydifferent from conventional approaches. Many
research programs lack access to these techniques
and technologies. A novel reactor-design program
aimed at moving from low to high levels of technicalreadiness could deliver the dramatic reductions of costand increases in performance and yields needed togain market parity for CO2-derived products. A priority
should be given to functionalizing existing materials
through new means, and to continuous production
approaches (as opposed to batch processes).

Process intensification
Most reactions where CO2 is a reactant rather thana product are either thermodynamically unfavorable
or kinetically slow. Thus, making practical processes
based around these reactions requires large
reactors, energetically expensive separations andNovember 2017

large materials inventories in recycle loops. Processintensification approaches that combine otherwise
separate chemical engineering unit operations (e.g.
reactions with separations) can address these issues.
For example, production of carbon monoxide fromCO2 by the reverse water gas shift reaction could besubstantially improved by the removal of water fromthe reactor, as could almost all low-temperatureelectrochemical conversion routes. Another example
is the combination of CO2 separation with reactions
to produce intermediates in CO2U processes orCO2-based products. Research and development
should focus on identifying opportunities for processintensification in CO2U.

New methods for elemental carbon
production
Although durable carbon materials are an attractive
future form of carbon utilization, today there arelimited approaches for converting CO2 directly into
carbon products. Significant levels of basic research inthis area could be expected to result in new pathways
and increased usability of the carbon produced byexisting pathways. The benefits of this research will be
as important to efficiency as to carbon utilization, andit should be prioritized accordingly. A future economy
where carbon fiber is cheap enough to be a common
component of automobiles is indeed attractive.
Because of the early stage of this research, it will
be necessary to plan for scale-up and production
R&D efforts as the bench results become available.
Early work in examining the synergies with molten
carbonate fuel cells is an early avenue to pursue here.

Materials substitution
While some CO2-based products compete directlywith essentially identical products (for example, formicacid), others will offer improved performance. One
example is the use of new building materials such ascarbon-fiber-reinforced concrete, which can substitutefor conventional rebar (steel-reinforced concrete) andallow advances in design and cost reductions, while
delivering emissions-reduction benefits across thelife cycle. Similarly, the use of carbon fiber insteadof steel or aluminum in automobile construction
leads to lighter vehicles and obvious energy savings.
Identifying use cases where CO2-based products cansubstitute for materials that are significantly different,
November 2017

while providing equal or improved performance,
is an important area for further research. The
consideration of how to make those materials with
low-emissions processing should be an importantpart of the evaluation of their usefulness. The use ofcarbon-based materials created by nature, although
not considered in this report, shares that same needfor simultaneous analysis of efficiency, lifetime andemissions footprint.

Low-carbon energy supply and delivery
Many CO2 schemes are predicated on a large supply of
low-cost, low-carbon renewable electricity. While thecost of renewable electricity is falling rapidly and theinstalled capacity is growing almost everywhere in theworld, the character of the energy delivered is variable
by its nature and not suitable for conventional 24-7
industrial operations. For example, high temperaturesystems (e.g. electrolyzers) are best operated atrelatively steady state, and are much less efficientand reliable when operated variably. Schemes toprovide low-carbon electricity with characteristics
suitable for industrial-scale operations must be
developed. This could be via facility-level integrated
systems of renewable generation with sufficientstorage capacity to maintain industrial production, or
continued development of such systems at the gridscale. Adaptation of CO2U processes to better handle
variable electricity inputs is also critical.
The energy delivery challenge could also be mitigatedby the placement of CO2U facilities in optimal
locations where a steady low-carbon energy supply isavailable. It is possible that the regional availability of
low-carbon energy will drive the placement of carbonutilization industries (as it has in other sectors, such asaluminum smelting).

Collocating and integrating CO2U with
CO2 capture
Most studies of CO2 utilization assume that CO2 isreadily available, but, unless it is captured from the air,it will always have to be transported and occasionallystored. For example, compression and transport ofCO2 over long distances is particularly costly, especiallywhere it is decompressed for use. Thus, it may be
advantageous to co-locate carbon capture andutilization facilities, even making utilization part ofthe carbon-capture process, avoiding CO2 transport47

altogether. For instance, many hydrogenation schemes
are exothermic, making process heat available forother activities. Integration with a carbon-capturesystem using heat (e.g. to regenerate solvents) could
make excellent use of that resource.
Discussions about the synergies between CO2U
processes and CO2 capture have been focused on
integration with power plants, but it is clear that CO2
utilization will be a significant part of industrial sectors
beyond electricity generation. These integration
options need to be explored. These industrial synergies
may have major impacts on the economics of specific
CO2 utilization approaches.

Reducing the CO2 footprint for raw
materials
A similar problem arises for the use of CO2 tomake aggregate and cements requiring additional
magnesium and calcium. These additional materials
are heavy and not available everywhere. While thosecations are widely available in oceans and volcanic
rocks, it is not easy to extract them for use. In thecase of oceans, removing them releases CO2 to theatmosphere—improved methods are needed to avoid
this problem. In the case of rocks, methods are needed
to remove the useful cations for use elsewhere, or tobring CO2 and the rocks together by some means. The
movement of goods or CO2 across large distances isa major detractor from the climate benefit of CO2U.
Research on approaches that minimize the carbon
footprint from the supply of raw materials is needed.

carried over into the product. The amount added cantherefore be a small difference.
Measurements of how much CO2 was deliberately
added to a product could take the form of isotopic
measurements, or validated difference measurementsfor production systems. Concrete and aggregates area particularly difficult case because the materials are
hard and cannot easily be dissolved for analysis. Smalldifferences in carbon content can have a large impact
on carbon utilization in such a large market. These
validation tools may be thought of as partially “closing
the books” on the life cycle analysis tools that was
discussed at the beginning of the chapter.

Regulation and standards
Finally, virtually all markets mentioned here aretouched by regulation and voluntary standards, theimpacts of which must be clearly understood if CO2U isto be successful. In general, individual developers takea very large risk in trying to get new classes of products
accepted in the necessarily complex regulated andstandardized markets for construction and highstrength materials. Collaborative efforts between
engineers, scientists and policy experts to synthesize
information on CO2-based products and their potential
contributions to the portfolio of climate solutions isneeded.3 Research in this space can also contribute to
the development of new approaches to performancebased regulations and standards—reducing barriers toentry in the market for new and innovative products
or products made in new ways, such as CO2-based
products.

Tools for lifecycle validation
Today assessment of the life cycle impact of products
is typically based on bottom-up modeling of materials
and energy flows, often using relatively sparse data.
There are few tools to analytically determine theultimate carbon content of products, and the origin ofthat carbon. This is particularly important in products
like concrete, where there are many opportunities forCO2 to escape from the process. This is complicatedby the fact that the raw materials for concrete andaggregates (such as limestone) naturally contain
substantial amounts of carbon, some of which is

48

1

Sonia Yeh et al., “A Review of Low Carbon Fuel
Policies: Principles, Program Status and Future
Directions,” Energy Policy 97 (October 2016): 220–34,
doi:10.1016/j.enpol.2016.07.029.

2

Matt Kocoloski et al., “Addressing Uncertainty in
Life-Cycle Carbon Intensity in a National Low-Carbon
Fuel Standard,” Energy Policy 56 (May 2013): 41–50,
doi:10.1016/j.enpol.2012.08.012; Yeh et al., “A Review
of Low Carbon Fuel Policies.”

3

See, for example the work of the EnCO2re project:
http://enco2re.climate-kic.org/

November 2017

Chapter 7:

Policy Options
Well-designed policies can help start and build markets
for CO2U products. Poorly-designed policies can stifle
such markets. The details of government policies—on
R&D, taxes, regulation, procurement and more—will
play an important role in the growth of CO2U productmarkets in the decades ahead.
The case for policies to support CO2U products isstrong. First, CO2 emissions are a classic externality.
Market forces alone will not control CO2 emissions.1
Second, R&D is essential for many CO2U products. Yet
companies do not invest in the socially optimal levelof R&D, especially early-stage R&D, in part because
they are unlikely to see results within time frames
important to most corporate managers.2 Government
support for R&D is therefore essential. Third, some
CO2U products will compete against well-establishedincumbents that have benefitted from policy support
in years past.
Different policies will be appropriate in different
jurisdictions, depending on public attitudes, regulatory
traditions and local circumstances. Some countries
favor taxes to achieve environmental objectives, forexample. Others reject taxes and favor regulatory
approaches. Some countries have strong research
institutions and deep experience with research anddevelopment programs, while others do not.
This chapter describes and discusses nine policies
that could play an important role in promoting CO2U
products.

November 2017

Government support for R&D
National governments spend roughly $15 billion
annually on research and development for clean
energy technologies.3 Yet support for R&D on CO2
utilization is modest. A significant increase in funding
in this area could speed deployment of CO2U
technologies and yield important dividends.
This roadmap identifies a number of priority areas for
R&D investment for CO2 utilization. They include:■■ Improving the understanding of the process

conditions for forming various types of carbon
materials;■■ Investigating alternative carbonate electrolytes andmixtures;■■ Developing pilot-scale electrolysis facilities that candemonstrate higher material throughput for carbon
materials;■■ Improving design of catalysts for thermochemical
pathways;■■ Modeling of CO2 activation on metal surfaces forelectrochemistry; and■■ Modeling for co-catalysts in photochemical
pathways.
In December 2015, heads of state from more than 20
countries announced Mission Innovation, a coalition
dedicated to accelerating clean energy innovation.
Member governments (including Japan, China, theUnited Kingdom, Germany and Saudi Arabia) pledged
to double R&D on clean energy within five years. The
increase in R&D budgets from these countries in thenext few years offers an important opportunity toscale up government R&D funding for CO2 utilization,
including in the areas noted above. A focus on CO249

utilization could form an important part of the R&D
portfolio of all Mission Innovation governments.
In November 2016, the Mission Innovation countries
committed to seven Grand Challenges, including
one for CCUS with a focus on CO2U.4 In September
2017, the United States and Saudi Arabia co-chaired
a Mission Innovation CO2U workshop in Houston
attended by experts from many nations. The workshop
provided material to assist Mission Innovation in
expanding R&D on CO2U.
The United States helped launch Mission Innovation
and remains a member. Although the U.S. is unlikely
to fulfill its overall doubling pledge under the Trumpadministration, the U.S. Department of Energy
awarded $5.9 million in grants for CO2U projects in
February 2017 and an additional $4.8 million for CO2U
projects in August 2017.5 CO2 utilization has won
bipartisan support in the U.S. Congress and could be
an area in which U.S. government R&D spending will
increase in the years ahead.

Carbon priceA price on carbon dioxide emissions, whether throughan emissions trading program or tax mechanism,
provides an important incentive to cut emissions.
Carbon pricing programs are now in place in theEuropean Union, California, nine northeastern U.S.
states, most of Canada and seven Chinese provinces.
The Chinese government plans to launch a nationwide
emissions trading program for carbon dioxide in 2017.
A carbon price can create incentives for CO2 utilizationin two ways. First, capturing CO2 and using it in an
economically valuable product could be the cheapest
compliance strategy for some emitters. In the shortterm this may be unlikely in most cases due to the highcost of CO2 capture and conversion. However as capture
and conversion costs decline, there will be moreinstances in which this is a company’s best compliancestrategy. Second, a carbon price may help incentivize
private-sector investments in research and development
on CO2 utilization, if market participants expect theprice to endure for the medium or long term.
Carbon pricing regimes do not automatically provide
incentives for CO2 utilization. That depends on theirstructure and details. The European Union’s Emissions
Trading Scheme, for example, credits a CO2 source
for any CO2 transferred from its facility “for the50

purpose of long-term geological storage.” No credit isavailable for CO2 transferred for use in CO2 products.6
If policymakers wish to provide credits for CO2 used in
products in carbon-pricing regimes, they will generally
need to specify that as part of the program design.

Tax incentives
Tax incentives can play an important role in helping
spur development of clean-energy products. In
Norway, for example, generous tax incentives helped
electric vehicles capture more than 40% of the new
car sales market in 2016. Such incentives could play asimilar role in building the market for CO2 products. Tax
incentives could be available to companies that invest
in R&D for CO2 utilization, for example. They could also
be available to buyers or sellers of CO2 products.
Such a proposal has recently been introduced in the
U.S. Congress. Under current U.S. law, tax credits areavailable for CO2 used in enhanced oil recovery orsequestered in geologic reservoirs. The FUTURE Act
would extend the tax credit to CO2 sequestered inmarketable products, ranging from $30-50/ton of CO2
captured and bound.7 The bill was introduced in July
2017 with bipartisan support and endorsed by bothfossil-fuel companies and environmental groups.
This type of focused, direct incentive can have asignificant impact. However, to the extent the objectiveof the tax credit is to cut CO2 emissions in the short-term,
it will be important to establish eligibility criteria that take
into account (i) the life cycle emissions associated withthe product, and (ii) the permanence of the removal of
CO2 from the atmosphere due to the product.

Mandates
Government mandates can be effective in helping
build markets for clean-energy products. In the UnitedStates, many state governments require utilities topurchase a minimum percentage of their power fromrenewable sources (renewable portfolio standards). In
India, a similar requirement is imposed by the Ministryof New and Renewable Energy. These requirements
have been important to the early growth of wind andsolar power in both countries.8
Other experiences suggest caution, however. The
United States federal government has mandated theuse of cellulosic ethanol in fuel supplies for almost a
decade. Nevertheless, the cellulosic ethanol industry
November 2017

remains in its infancy and waivers to that requirement
have been granted on a regular basis. Technologyforcing requirements—in which governments require
private actors to meet standards that are not yet
technically achievable—have been successful in someinstances but not in others.9
There may be instances in which government
mandates could help build markets for CO2 products.
Large concrete manufacturers could be required to
produce a certain amount of their product using CO2
curing, for example. Makers of carbonate aggregates
could be required to produce a certain amount of theirproduct by conversion of CO2. These processes arewell understood and technologically viable today, butthey are more expensive than conventional methods
and manufacturers have little incentive to adopt them.
Government mandates could help overcome that,building markets for the use of CO2 and driving down
costs as use of the technologies scales up.

Pipeline development
To be converted into products, CO2 must either beused at the point of capture, transported in a vehicle(truck, train or ship) or moved by pipeline. Pipeline
networks are likely to be the cheapest way to transport

CO2 over long distances and could play a critical role inhelping CO2 utilization to flourish.
Today the world’s largest CO2 pipeline network is in
the United States, which has 4,500 miles of pipelines
linking CO2 sources to sites for enhanced oil recovery.
(See map below.) Roughly 80% of the CO2 in U.S
pipelines is from natural geologic reservoirs. Europe
has roughly 620 miles of CO2 pipelines, mainly totransport CO2 to depleted oil and gas fields. (Oneproject in the Netherlands distributes CO2 from a Shell
refinery to over 500 greenhouses.) Early planning isunderway to develop a more extensive CO2 pipeline
network in Europe. There are a few CO2 pipelines in
the Middle East, Asia and Australia.10
For many CO2U technologies, other reactants besides
CO2 are required, the most common of which ishydrogen. Transporting hydrogen can be accomplished
via several methods. It will be important to evaluate
the transportation and availability issues surroundinghydrogen for some CO2U products, and a specificevaluation of options may be required, including
pipeline construction; road, rail or ship transportation;and physical co-location with a hydrogen source.
Building pipeline networks can involve coordination
among many parties and long lead times. In part as a

CO2 to Canada
Great Plains coalgasification plantMontana

North Dakota

Idaho

LaBarge

Wyoming

South Dakota

Nebraska
Utah

Colorado

McElmoDome

Sheep Mountain

RidgewayCO2
discovery

KansasBravo
Dome

ArizonaAmmonia plant
Oklahoma

Arkansas

Jackson DomeNew Mexico

Terrell, Puckett, andMitchell gas plants

U.S. CO2 pipeline network

Texas

AlabamaLouisiana
Mississippi

Source: Michael Bernard,
Clean Technica (2016)11
November 201751

result, governments can often play an important role:
Governments can:■■ Help coordinate planning processes, convening

relevant stakeholders;■■ Facilitate regulatory approvals; and■■ Assist with pipeline financing.
These steps can help launch and build markets for
CO2U products.

Government procurement
In many countries, government procurement makes
up more than 10% of GDP.12 Many governments arelarge consumers of cement (for construction andinfrastructure projects) and liquid fuels (for fleet
vehicles and aircraft).
Government purchases can play an importantrole in starting and building new product markets.
First, government purchase contracts can provide
developers and manufacturers of new products withan assured market, which can be especially importantin securing debt capital. Second, government
purchases can help establish standard technicalspecifications for new products, which can help
catalyze efficient supply chains.
Several CO2U technologies may be especially goodtargets for government procurements, including CO2cured cement and CO2-based aggregates. These could
be included in government procurement guidelines
for construction projects.13 Governments could also
target CO2-based fuels for procurement. (The U.S. Navyhas had a similar program for the purchase of drop-in
biofuels.) As technologies mature, this could expand tocarbon fiber, chemicals and other products.

Life cycle assessments
As noted previously, evaluating the climate benefits ofa CO2-based product requires a life cycle assessment(LCA). (See discussion in Chapter 5.) Governments
could help with LCAs for CO2 products in at least
two ways. First, governments could help standardize
methodologies for life cycle assessments, by convening
relevant stakeholders and issuing reports or guidelines
based on the inputs received. (This should be pursued
in coordination with private-sector efforts to improveand standardize CO2U LCA, such as the efforts by The

52

Global CO2 Initiative and X Prize.) Second, governments
could help fund research on LCAs for individual CO2
products or product categories. These LCAs may
depend on data that is expensive or difficult for private
parties to collect, giving governments a potentially
important role.
In addition, policy design with respect to CO2 utilizationmust pay close attention to the need for LCAs. To
the extent that the goal of government policies
promoting CO2 utilization is short-term reduction of
CO2 emissions, LCAs are essential. The FUTURE Act
mentioned above provides that the U.S. Departmentof Energy and U.S Environmental Protection Agency
will develop guidelines for LCAs in connection with theaward of tax credits for CO2 utilization.15

Certification and testing
Certification plays an important role in many productmarkets, from electronics and pharmaceuticals to foodand sustainable forest products. Certifiers typicallyvalidate product quality and/or compliance withcertain criteria. Widely used certification organizations
include UL, ASME and ASHRAE.
In addition to assuring quality or compliance,
certification can act as a market barrier. New products
must often go through multi-year assessment andtesting processes to ensure that standards are met.
These processes perform important social functions—
including safety assurance—but can slow the adoptionof products made in new ways, such as with CO2.
Governments typically do not run certification
processes or dictate results. However, governments
can fund the testing of products by organizations
such as UL, ASTM, ASME and ASHRAE in order to help
facilitate or speed the certification process. This could
be especially important for CO2-based concrete or
carbonate aggregates, which will need to demonstratecompliance with industry quality standards before
widespread adoption. In particular, government
support could include international meetings anddiscussions to help facilitate commercial development
and trade of these products through international
standards coordination and cross-linking. Governments
could also coordinate their testing and certification
requirements to ensure that a CO2U product certified
within one country will not need to be recertified

November 2017(leading to additional expense and delay) to enter
another country’s market.

Product labelingLabels indicating the environmental qualities of
products can increase demand for those products.16
In fields such as building energy efficiency, carbon
neutrality, forests and fisheries, many private
voluntary organizations define criteria for suchlabels. Such organizations often evaluate whether
individual products meet those criteria as well.17
Many governments do the same. Prominent examples
include the U.S. Energy Star and Energy Guide
programs, the Japanese Energy Efficiency Labelprogram, and the EU Energy Labeling Directive.
Two related strategies in this area could help increasedemand for CO2U products. First, products could belabelled to indicate the presence of captured CO2.
Second, existing labeling schemes could be modified togive credit for the use of CO2 in a way that reduces life
cycle emissions. Governments are well-positioned tolaunch such programs with the attention they attract,
the resources they command and prior experiencein this area. Any consumer-facing product with thepotential for CO2U could qualify. Leading candidates
may include coatings, adhesives, sealants andrelated plastics products, as well as CO2-based fuels.
Governments could also work with voluntary labelingprograms such as LEED to include credit for buildingsthat use CO2U-based construction materials.
1

2

See Sir Nicholas Stern, Stern Review on the Economicsof Climate Change (2006) http://webarchive.
nationalarchives.gov.uk/+/http://www.hm-treasury.gov.
uk/sternreview_index.htm. See also Alison Benjamin,“Stern: climate change a market failure” Guardian(November 29, 2007) (quoting Sir Nicholas Stern –"Climate change is a result of the greatest market
failure the world has seen”) https://www.theguardian.
com/environment/2007/nov/29/climatechange.
carbonemissions
See Robert Stavins, “Repairing the R&D Market Failure,”
Environmental Forum (Jan/Feb 2011) https://scholar.
harvard.edu/files/stavins/files/column_40.pdf; Kenneth
Gillingham and James Sweeney, “Market Failure andthe Structure of Externalities” (July 2008) http://
environment.yale.edu/gillingham/GillinghamSweeney_
MktFailureStructureExternalities_proof.pdf
November 20173

See http://mission-innovation.net/our-work/baselineand-doubling-plans/

4

See Mission Innovation, Carbon Capture Innovation
Challenge -- http://mission-innovation.net/ourwork/
innovation-challenges/carbon-capture-challenge/

5

Department of Energy Invests $4.8 Million in Projects
to Advance Beneficial Use of CO2 (August 10, 2017)https://energy.gov/fe/articles/department-energyinvests-48-million-projects-advance-beneficial-use-co2

6SCOT Project, EU-ETS to Incentivise CO2 Utilization?
http://www.scotproject.org/images/Briefing%20
paper%20EU%20ETS%20final.pdf

7

FUTURE Act at 45Q(f)(2) https://www.congress.gov/
bill/115th-congress/senate-bill/1535/text

8

See Tom Kenning, “Revision to ‘single most important
policy’ to drive solar ready for approval,” PV Tech
(November 9, 2015) -- https://www.pv-tech.org/news/
intersolar-india-revision-to-single-most-importantpolicy-todrive- solar-re9

See generally David Gerard and Lester Lave,“Implementing Technology-Forcing Regulations,”
Technological Forecasting and Social Change (2005)
http://faculty.lawrence.edu/gerardd/wpcontent/
uploads/sites/9/2014/02/18-TFSC-Gerard-Lave.pdf

10

USDOE, A Review of the CO2 Pipeline Infrastructure in
the U.S. (April 21, 2015) at p.1 https://energy.gov/sites/
prod/files/2015/04/f22/QER%20Analysis%20- %20
A%20Review%20of%20the%20CO2%20Pipeline%20
Infrastructure%20in%20the%20U.S_0.pdf; Global CCS
Institute, CO2 Pipeline Infrastructure (January 2014)
http://ieaghg.org/docs/General_Docs/
Reports/2013-18.pdf; Linde Group
http://www.the-lindegroup. com/en/clean_technology/
clean_technology_portfolio/co2_applications/greenhouse_supply/index.html; CO2 Europipe
http://www.co2europipe.eu/

11Michael Barnard, “Climate Capture is Expensive
Because of Physics,” Clean Technica (January 19,2016) https://cleantechnica.com/2016/01/19/carboncapture-expensive-physics/

12

Esteban Ortiz-Ospina and Max Roser, “Public Spending”(2017) https://ourworldindata.org/public-spending/13

See, e.g. “Comprehensive Procurement Guidelines forConstruction Products”, U.S. EPA website.

53

14

“Biofuels are included in latest U.S. Navy fuelprocurement”, U.S. Energy Information Administration(July 25, 2014)

15

FUTURE Act at 45Q(f)(2) -- https://www.congress.gov/
bill/115th-congress/senate-bill/1535/text

16

See Jo Bowman, “Green Branding” (March 2009)http://www.wipo.int/wipo_magazine/en/2009/02/
article_0011.html; Jenny Chin-Hwa et al., “Will
American consumers pay more for eco-friendly labeledcanned tuna?” (May 2017) http://www.sciencedirect.
com/science/article/pii/S0308597X16304894

17

See Ecolabel Index http://www.ecolabelindex.com/
ecolabels/?st=country,us54

November 2017

Chapter 8:

Findings andRecommendations
Key findings
CO2U can be an important tool for achieving a wide
set of policy objectives. These include stimulating andrevitalizing industries, creating jobs and delivering
environmental benefits (notably climate benefits).
Some of the most intriguing applications of CO2U arein early developmental stages. These include novel
methods of converting CO2 into chemicals, fuels andlong-lived products. These appear to have the potential
to displace carbon-intensive products in large volume
with relatively modest material and energy costs.
With a strengthened and expanded innovation
agenda, CO2U could deliver significant benefits ineach of the three sectors discussed in this report.
This conclusion is based on potential climate impacts,
market values and technical improvements (based onthermodynamic and engineering limits), as well as the
R&D needed to make many products cost-competitive.
More work is needed on life cycle analyses. For many
CO2U applications, key data sets are needed for accurate
and precise estimates of carbon reductions through LCA.
Some existing methodologies require refinement for
LCAs to undergird regulatory and policy decisions.
Similarly, many CO2-based products lack standards
or acceptance by standards organizations. While

November 2017

existing market standards for some products such as
ethylene and fuels may suffice, existing performanceand compositional standards for many other products(including cements, carbon fiber, composites and new
chemicals) will likely limit access to market for new
products.

Key recommendations
Research, development and analysis
1. A sustained innovation agenda is needed to
rapidly develop and improve CO2U processes andproducts. This will also accelerate their entry into
commercial markets.
2. Part of that innovation agenda involves assessment
and analysis of potential CO2U markets andpotential climate benefits.
3. Dedicated and sustained R&D programs haverepeatedly proved valuable in delivering large
innovations. Multi-year planning and investment isrequired.
4. A wide range of potential R&D investments
could be merited. Individual countries, states
and regions can tailor investments around their
existing infrastructure, institutions and markets.
However, a set of scientific discipline-based basic
and applied research appears broadly valuable,
including materials science (especially catalysis
focused on conversions) and reactive mineral
physics. Investment in enabling technologies (likeadvanced manufacturing and supercomputing)also seems promising.

55

Cross-cutting issues
5. Life-cycle analysis (LCA) work on CO2U products
should receive targeted and dedicated support
to improve data and methodologies. In addition,
governments and key stakeholders should create
national and international working groups tobetter share results and standardize their outputs.
6. Similarly, technology developers, CO2U productvendors, and CO2U product users should work
together to accelerate the development of national
and international product standards. This should
be done in partnership with national standards
organizations (e.g. NIST in the U.S.) and theInternational Organization for Standardization (ISO).

Policy7. Governments should recognize CO2U as apotential pathway to environmental andeconomic benefits, including climate benefits.
They should consider including CO2U in formal
climate commitments (e.g. NDCs within the Paris
Agreement).
8. Governments should consider policy measures tosupport market entry of CO2U products. These
could vary in form (e.g. tax credits, subsidies,procurement mandates, etc.) but should be aimed
at stimulating market adoption of CO2U.
9. Governments should expand a CO2U innovation
agenda that includes increased R&D and related
innovation.
10. Governments should provide regulatory clarity
through the adoption and use of LCAs and productstandards.

Final thoughts
As global markets evolve under the Paris Agreement
and its successors, CO2U will likely play a larger role inproviding opportunities for action. Although there isopportunity for the current technology set to improveand evolve, the progress to-date is noteworthy.
Commercial interest in CO2U has grown dramaticallyin just the last two years. We see CO2U as a key
component to a new carbon economy, in which CO2
is considered a conventional feedstock for cradle-tocradle, circular economy networks. These findings andrecommendations will similarly evolve over time andchange focus. The merit in future work will flow directly
and indirectly from commitments made by leaders inindustry, finance, government and innovation. Fortune
will favor the experienced and the quick.

We are deeply grateful to the Ministry of Economy, Trade and Industry (METI) and
New Energy and Industrial Technology Development Organization (NEDO), Japan, for launchingand supporting the ICEF Innovation Roadmap Project of which this is a part.

Portions of this document were prepared by LLNL under Contract DE-AC52-07NA27344.
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November 2017