ADIPIC ACID PRODUCTION
ISSUE PAPER

October 3, 2019

ClimeCo Corporation
One E Philadelphia Ave
Boyertown, Pennsylvania 19512(484) 415-0501
climeco.com

Adipic Acid Production Issue Paper

Adipic Acid Production Issue Paper
Prepared by:
Version:Version Date:

Bill Flederbach & James Winch, ClimeCo Corporation
1.0 (Publish Issue Paper)
10/03/2019

This issue paper, initially developed by ClimeCo Corporation, is for use by the Climate Action Reserve inthe development and evaluation process for a standardized offset project protocol reducing N2Oemissions from adipic acid production.

Contact Information:
Bill Flederbach, Jr.
ClimeCo Corporation
One E Philadelphia Ave, Boyertown, Pennsylvania 19512(484) 415-0501
wflederbach@climeco.com
Tip Stama
ClimeCo Corporation
One E Philadelphia Ave, Boyertown, Pennsylvania 19512(484) 415-0501
tstama@climeco.com

Lauren Mechak
ClimeCo Corporation
One E Philadelphia Ave, Boyertown, Pennsylvania 19512(484) 415-0501
lmechak@climeco.com

2Adipic Acid Production Issue Paper

Table of Contents
1.

2.

3.

4.

Introduction .......................................................................................................................................... 4
1.1.

Adipic Acid Production History and Market.................................................................................. 4

1.2.

Adipic Acid Manufacturing Process .............................................................................................. 5

Emission Controls at Adipic Acid Plants ................................................................................................ 7
2.1.

Existing Controls............................................................................................................................ 7

2.2.

Potential Controls and Eligible Project Activities .......................................................................... 7

Evaluation of Additionality.................................................................................................................... 9
3.1.

Climate Action Reserve Additionality Tests .................................................................................. 9

3.2.

Risk of Over-Crediting and Secondary Effects............................................................................... 9

3.2.1.

Evaluation of Secondary Effect Potential in the United States ........................................... 11

3.2.2.

Baseline Setting ................................................................................................................... 12

3.2.3.

Summary of Additionality ................................................................................................... 13

Evaluation of Legal Requirements ...................................................................................................... 14
4.1.

U.S. Regulations .......................................................................................................................... 14

4.1.1.
4.2.
5.

U.S EPA GHG Permitting Requirements under the Clean Air Act ....................................... 14International Regulations............................................................................................................ 15

Discussion of Protocol Composition ................................................................................................... 15
5.1.

Project Scope and Boundaries .................................................................................................... 16

5.1.1.

Facility Age Eligibility ........................................................................................................... 16

5.1.2.

Project Boundaries .............................................................................................................. 16

5.1.3.

Geographical Boundaries .................................................................................................... 17

5.2.

Quantifying GHG Emission Reductions ....................................................................................... 17

5.2.1.

Standardized Baseline Calculations .................................................................................... 17

5.2.2.

Project Emission Calculations ............................................................................................. 18

5.2.3.

Leakage ............................................................................................................................... 18

6.

Monitoring and Verification ................................................................................................................ 18

7.

Environmental and Social Impacts ...................................................................................................... 19

8.

References .......................................................................................................................................... 20

3

Adipic Acid Production Issue Paper

1. Introduction
This Issue Paper reviews the potential to reduce GHG emissions and generate voluntary offset credits, orClimate Reserve Tonnes (“CRTs”), by creating an Adipic Acid Production Protocol through the Climate
Action Reserve (“Reserve”). It summarizes the existing literature, data and quantification methodologies
related to adipic acid emissions abatement and leverages lessons-learned from historical international
projects. Because adipic acid production and GHG abatement technology closely mirrors the production
and abatement of greenhouse gases (“GHGs”) from nitric acid production, this Issue Paper will rely heavily
on the Reserve’s existing Nitric Acid Production Protocol (“Nitric Acid Protocol”).1

1.1.

Adipic Acid Production History and Market

Production (kilotons adpic acid)Emissions (million metric tons CO2e)

Adipic Acid (HOOC(CH2)4COOH), also
known as hexanedioic acid, is a
Adipic Acid Aproduction and Emissions 2010 2017
chemical compound commonly used
121200
as a precursor to produce nylon 6,6
10
1000
polyamide through its reaction with
1.6-hexamethylenediamine. In 2017
8800
(the most recent date for which data
6600
are available), adipic acid facilities in
the United States generated 7.4
4400
million metric tons CO2 equivalent
2
200(“tCO2e”).2,3,4 Between 2012 and2015, aggregate GHG emissions and002010 2011 2012 2013 2014 2015 2016 2017
production remained approximately
steady, with some fluctuation.5 In
Total Emissions
Production
2015, INVISTA shut down their
Orange, Texas production facility, Figure 1. Emissions and production data for adipic acid facilities in the UnitedStates.
which had an annual capacity of
220,000 metric tons of adipic acid per year.6 This resulted in a moderate decrease in aggregate U.S.
production accompanied by a relative increase in emissions, indicating that local production shifted from1

Climate Action Reserve, “Nitric Acid Production Project Protocol Version 2.2,” April 18, 2019,http://www.climateactionreserve.org/how/protocols/nitric-acid-production/.
2
United States Environmental Protection Agency, “Inventory of U.S. Greenhouse Gas Emissions and Sinks: 19902017,” April 11, 2019, https://www.epa.gov/sites/production/files/2019-04/documents/us-ghg-inventory-2019main-text.pdf.
3
United States Environmental Protection Agency, “Ascend - Cantonment, FL 2014 GHG Facility Details,” EPA Flight,
accessed June 25, 2019, https://ghgdata.epa.gov/ghgp/service/html/2014?id=1004962&et=undefined.
4
United States Environmental Protection Agency, “Invista - Victoria, TX 2017 GHG Facility Details,” EPA Flight,
accessed June 25, 2019, https://ghgdata.epa.gov/ghgp/service/html/2017?id=1001781&et=undefined.
5
United States Environmental Protection Agency, “Inventory of U.S. Greenhouse Gas Emissions and Sinks: 19902016.”
6
ICIS, “US INVISTA to Close Adipic Acid Plant in Texas,” Icis, October 6, 2015,
https://www.icis.com/explore/resources/news/2015/10/06/9930535/us-invista-to-close-adipic-acid-plant-intexas.

4Adipic Acid Production Issue Paper

the shuttered facility to an existing higher-emitting facility. Currently, only two adipic acid facilities remain
active in the United States: The Ascend plant in Pensacola, Florida and the INVISTA plant in Victoria, Texas.
Adipic acid production in the United States represents a substantial source of GHG emissions from very
few facilities. As such, the industry has an enormous potential to reduce emissions given the appropriate
incentives to install control technologies.

1.2.

Adipic Acid Manufacturing Process

There are two stages to adipic acid production. First, cyclohexane is air-oxidized to form acyclohexanone/cyclohexanol mixture (Figure 2). In the second stage this mixture is chemically oxidized,
creating N2O, the GHG of concern, as an unavoidable byproduct that is emitted in the facility’s off gas(Figure 3). Adipic acid and N2O are created in proportional molar ratios (i.e., for every molecule of adipic
acid produced, a molecule of N2O is produced as a byproduct.) The process is represented by the following
chemical reaction7:(CH2)5CO [cyclohexanone] + (CH2)5CHOH [cyclohexanol] + wHNO3 -> HOOC(CH2)4COOH [adipic acid] + xN2O + yH2O

Figure 2. Diagram depicting the first step of the adipic acid production (Figure from U.S. EPA Adipic Acid Production report).87

United States Environmental Protection Agency, “Inventory of U.S. Greenhouse Gas Emissions and Sinks: 19902016.”
8
United States Environmental Protection Agency, “Adipic Acid Production,” July 1994,
https://www3.epa.gov/ttn/chief/ap42/ch06/bgdocs/b06s02.pdf.

5Adipic Acid Production Issue Paper

Figure 3. Diagram depicting the second step of the adipic acid production (Figure from U.S. EPA Adipic Acid Production report).9

The off gas from adipic acid plants contains several different molecules, many of which are detrimental tothe environment (Table 1). One challenge facing the adipic acid industry is the trade-off between abating
different types of pollutants in a cost-effective manner, which is discussed in detail later in this Issue
Paper.
Table 1. Typical composition of the off gas created in adipic acid production.10

Chemical or Common Name

Chemical Formula

Molar Percent of Off Gas

Nitrous Oxide

N2O

30.5%

Nitrogen Oxide

NOx

0.7%

Carbon Dioxide

CO2

6.0%

Carbon Monoxide

CO

0.03%

Ozone

O2

3.9%

Water

H2O

2.0%

Dinitrogen

N2

57.0%

Volatile Organic Compounds (“VOCs”)

Many

0.03%

9

United States Environmental Protection Agency.
R. A. Reimer et al., “Abatement of N2O Emissions Produced in the Adipic Acid Industry,” Environmental Progress
13, no. 2 (1994): 134–37, https://doi.org/10.1002/ep.670130217.
106

Adipic Acid Production Issue Paper

2. Emission Controls at Adipic Acid Plants
2.1.

Existing Controls

Currently, most adipic acid facilities are fitted with some N2O abatement technology. Although there isno federal requirement to control N2O emission in the United States (except under limited circumstances,
see Section 4.1 “Federal Regulations”), all Western industrialized countries voluntarily installedabatement technology in the 1990s.11
The most appropriate type of control technology can be highly facility specific. The Ascend adipic acidplant has a Thermal Reduction Unit (“TRU”) installed, which abated approximately 83% of the facility’s
N2O emissions12 in 2017, whereas the INVISTA adipic acid plant abates using specially designed boilers
that generate steam from process-derived waste streams and N2O-specific selective catalytic reduction(“SCR”) systems, which achieved 97% abatement in 2017.13,14 Because adipic acid production is soemissions intensive, even after abating the majority of their emissions, these two facilities still released
7.4 million tCO2e in 2017 (see Figure 1), and thus have substantial opportunity for additional emission
reductions.

2.2.

Potential Controls and Eligible Project Activities

Adipic acid N2O abatement technology is similar to the abatement technology at nitric acid facilities. In
the Reserve’s Nitric Acid Protocol, abatement can either be secondary (abatement in the burner/ammonia
oxidation reactor [“AOR”] where the reaction occurs) or tertiary (abatement of the waste off gas
downstream of the AOR). However, unlike nitric acid production, adipic acid production cannot tolerate
the associated pressure change with secondary abatement. As a result, abatement is limited to installing
downstream technology to treat the facility’s off gas. Control technology falls into four types of systems,
outlined in Table 2.

11

Heike Mainhardt and Dina Kruger, “N2O Emissions from Adipic Acid and Nitric Acid Production,” accessed June25, 2019, https://www.ipcc-nggip.iges.or.jp/public/gp/bgp/3_2_Adipic_Acid_Nitric_Acid_Production.pdf.
12
United States Environmental Protection Agency, “Ascend - Cantonment, FL 2014 GHG Facility Details.”
13
United States Environmental Protection Agency, “Invista - Victoria, TX 2017 GHG Facility Details.”
14
INVISTA’s West Powerhouse (“WPH”) Victoria plant has a comparably high abatement level because it was
required to install GHG control technology as part of their Prevention of Significant Deterioration (“PSD”)
permitting under the Clean Air Act after a major source modification (40 CFR § 124.41). For more information, see
Section 3.1 “Federal Regulations”.

7Adipic Acid Production Issue Paper

Table 2. Review of potential control technologies at Adipic Acid plants.15

Abatement Type

Description

Example Equipment

Catalytic Destruction

Destroy N2O using a catalyst

Noble or precious metal catalysts

Thermal Destruction

Destroy N2O in using reducing flame
burners with pre-mixed methane or
natural gas.

Thermal Reduction Units

Recycling/Utilization
Technologies

Utilize N2O as a reactant or input toproduce other products.

Using N2O off gas as an oxidant toproduce phenol from benzene.

Recycle to Nitric Acid

Recycle N2O to create nitric acid byburning the gas at hightemperatures with steam.

Nitrogen recycling adiabatic reactor

Existing facilities can reduce their emissions beyond a business-as-usual level in two ways. First, they could
utilize their existing emissions control technology at a higher rate, or they could install new emissions
abatement control technology. Increasing the use of existing abatement technology is particularly
pertinent to U.S. adipic acid plants; as previously discussed, all plants were early movers in installingabatement technology. However, there are often barriers (financial or otherwise) that make it
impracticable to fully utilize the existing technology to abate N2O.
For example, if a facility has TRU, there can be a trade-off between N2O abatement and abating otherpotentially harmful pollutants such as NOx.16 Facilities can send their off gas to the TRU, which reduces
N2O17 but has only a limited capacity to reduce NOx emissions, or send their off gas to a NOx-specific SCR(“SCR de-NOx unit”), which reduces NOx emissions but not N2O emissions. The SCR de-NOx unit also createssome GHG emissions due to the ammonia used during operation. Because N2O is not regulated and NOx
emissions are regulated under the Clean Air Act, facilities will only utilize their TRUs when they are falling
below their legal NOx limits. In the absence of an offset system or a regulatory reason to reduce GHG
emissions, facilities have no incentive to make a capital investment to adjust their operations to eliminate
the NOx/N2O trade-off. With an incentive, a facility could increase TRU utilization by reducing NOx.
15

IEA Greenhouse Gas R&D Programme, “Abatement of Other Greenhouse Gases - Nitrous Oxide,” September
2000, https://ieaghg.org/docs/General_Docs/Reports/PH3-29%20nitrous%20oxide.pdf. IEA Greenhouse Gas R&D
Programme.
16
NOx is a volatile organic compound that reacts with sunlight to create ground-level ozone (O3), or smog. Ozone is
one of six criteria air pollutants regulated under the Clean Air Act (40 CFR part 50). Historically, a prevalent NOX
control system (non-selective catalytic reduction systems, or NSCR) also destroyed up to 90% of the N 2O emissions(Heike Mainhard and Diana Kruger, “N2O Emissions from Adipic Acid and Nitric Acid Production,” accessed June25, 2019, https://www.ipcc-nggip.iges.or.jp/public/gp/bgp/3_2_Adipic_Acid_Nitric_Acid_Production.pdf).
However, NSCR technology was replaced in the late 1970s by NOx-specific Selective Catalytic Reduction units(“SCRs”) that were more cost effective and provide targeted reduction for only NOx gases. Presently, both
remaining adipic acid plants in the United States are fitted with SCR de-NOx units.
17
TRUs generate some emissions from the natural gas combustion during their operation.

8

Adipic Acid Production Issue Paper

3. Evaluation of Additionality
3.1.

Climate Action Reserve Additionality Tests

In this section, we evaluate how an adipic acid project passes the Reserve’s thresholds for additionality.
In general, the Reserve requires that a project passes a standardized additionality test considering either
an emissions rate threshold, a practice or technology-based threshold, or other conditions or criteria.18
Both thresholds are potentially applicable to adipic acid GHG abatement projects in the U.S. However, thethreshold for an emissions rate may be very difficult to evaluate with the limited number of plants in the
U.S. Therefore, this Issue Paper will discuss the potential for a technology or practice-based threshold.
Although facilities have historically installed equipment to reduce GHG emissions, there is not a legal
requirement to abate above-and-beyond current levels. Facilities have no incentive to make the oftensubstantial capital investment to increase their GHG abatement levels. However, there is still an
enormous potential to abate incremental GHG emissions if a facility can either increase the utilization ofexisting technology or install more efficient GHG abating equipment.
Because existing facilities already utilize some GHG control technology, it is important to also ensure
emissions reductions are incremental or additional to any existing practices. The Reserve acknowledges
the challenges associated with a common practice or technology performance standard test in their
Program Manual (emphasis added):“A common rule of thumb for establishing performance standards is that they shouldmake eligible only technologies or practices that are not “common practice.” However,“common practice” is often difficult to define. Instead of adopting a simple rule fordefining “common practice” (as a threshold market penetration rate, for example) the
Reserve requires setting performance standards based on an overall assessment of themarket for GHG reductions and the risk of crediting too many non-additional
reductions.”
To comply with the Reserve’s standard evaluation of additionality, we will therefore focus on the market
for GHG reductions and the risk of over-crediting.

3.2.

Risk of Over-Crediting and Secondary Effects

International adipic acid abatement projects have faced historical criticism for creating secondary effects,
sometimes referred to as carbon leakage, and generating non-additional credits. The prominent thinktank Stockholm Environmental Institute’s 2010 assessment found that projects under first version of the
Clean Development Mechanism (“CDM”) adipic acid production protocol AM0021 (Version 1)19 caused a

18

Climate Action Reserve, “Program Manual,” September 1, 2015.
UNFCCC/CCNUCC, “Approved Baseline and Monitoring Methodology AM0021, ‘Baseline Methodology for
Decomposition of N2O from Existing Adipic Acid Production Plants’ Version 03,” February 27, 2009,https://cdm.unfccc.int/methodologies/DB/PC4EBQSJUB9IV2FS9TMQV8DFM3X6MZ.
19

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Adipic Acid Production Issue Paper

substantial shift in worldwide adipic acid production, resulting in an estimated 20% non-additional
Certified Emission Reductions (“CERs”).20
According to SEI, there were two primary carbon leakage drivers:
1. The protocol set the baseline N2O abatement emissions level at 0% (i.e., no abatement); and2. The value of the CERs created through abatement technology exceeded the value of the adipic
acid itself, creating perverse incentives.
These factors created an incentive for adipic acid production to shift from non-CDM projects to CDM
projects, and for individual CDM projects to increase production of adipic acid for the value of the carbon
credit rather than the actual adipic acid product.
Despite these issues, SEI acknowledged that CDM adipic acid abatement projects remained a largely
effective mechanism to reduce emissions, stating, “[t]he carbon market provided incentives for adipic acidproducers to abate N2O emissions to an extent which had previously not been achieved and which had
not been considered practical or feasible in the relevant technical literature.”21 In other words, although
the original CDM protocol left room for systematic abuse, the protocol created incentives that allowed
effective emission reduction equipment to be installed that would have otherwise been uneconomical.
A more recent analysis by the German think tank Öko-Institut, in collaboration with SEI, argued that given
an overall lack of incentive to abate GHG emissions for adipic acid projects, “this project type can beconsidered to be very likely additional. We recommend considering this project type as automatically
additional, as long as no regulations require N2O abatement.”22
These reports acknowledge that none of the adipic acid plants would have installed abatement
technologies in the absence of the incentives created by the carbon market. However, there is a risk ofover-crediting that should be thoroughly evaluated. Both reports suggest secondary effects can be largely
mitigated or completely avoided through careful protocol design.
SEI suggests that setting baselines based on emissions rates would be the most straightforward andefficient way to prevent secondary effects. This strategy was utilized in later Joint Implementation (“JI”)23
projects that had more stringent leakage protections and did not appear to have had any secondary
effects or carbon leakage.

20

Lambert Schneider, Michael Lazarus, and Anja Kollmuss, “Industrial N2O Projects Under the CDM: Adipic Acid - A
Case of Carbon Leakage?,” Stockholm Environmental Institute, October 9, 2010, 23.
21
Schneider, Lazarus, and Kollmuss.
22
Dr. Martin Cames et al., “How Additional Is the Clean Development Mechanism? Analysis of the Application of
Current Tools and Proposed Alternatives,” Öko-Institut, March 2019,https://ec.europa.eu/clima/sites/clima/files/ets/docs/clean_dev_mechanism_en.pdf.
23
Joint Implementation is a project-based mechanism similar to the CDM established under the United Nations
Framework Convention for Climate Change’s Kyoto Protocol that is applicable in countries classified as“developed” at the time of the Kyoto Protocol.

10Adipic Acid Production Issue Paper

In this Issue Paper, we will discuss why the incentive structures in the U.S. would not encourage secondary
effects. After, we will discuss best practices to implement careful and conservative protocol design thatwould eliminate any risk of carbon leakage including setting a rigorous baseline.

3.2.1. Evaluation of Secondary Effect Potential in the United States
Secondary effects (carbon leakage) may occur if a facility begins to over-produce their product because
the value of carbon offset creates a perverse incentive (“product gaming”). This occurred in early CDM
adipic acid abatement projects. If secondary effects occur, a portion of the offsets would be nonadditional and the activity could shift production away from other adipic acid production facilities
worldwide. In general, we believe this scenario will not occur in the United States for the following
reasons:
1. The value of voluntary carbon offsets in the United States is lower than historical CDM CER level
when product gaming occurred (average of $2.40 $/tCO2e in quarter 1 201824 compared to over
$18 USD/tCO2e25).
2. The Reserve’s protocol would only generate credits for the incremental emission reductions
above a baseline (to be discussed in Section 3.2.2.). As a result, U.S.-based projects would notachieve nearly the same volume of CERs as created under the CDM on a per-unit adipic acidproduced basis.
3. In the U.S., over-production is especially costly because the facility would need to increasingly
abate its NOx emissions.
Although an offset project may be financially attractive in the U.S., these factors all indicate that the
project alone should not bring a facility high enough value to justify increasing production exclusively forthe offset value. Even if U.S.-based voluntary credits rise in value to a level comparable to early CDM CERlevels, we believe that the decrease in credit issuance with a tighter baseline requirement would still
protect against leakage incentives.
To provide an example of the economic incentives that created secondary effects in early CDM projects,
SEI compared the financials of early CDM projects with later JI projects. According to SEI, JI projects hadbaseline historical abatement levels around 90%.26 By only crediting the incremental emissions beyond
individual facility’s abatement levels, the economic incentives for JI projects remained attractive but did
not appear to create the same highly skewed incentive structure (Table 3).

24

Kelley Hamrick and Melissa Gallant, “Voluntary Carbon Market Insights: 2018 Outlook and First-Quarter Trends”(Ecosystem Marketplace, August 2018), https://www.forest-trends.org/wp-content/uploads/2018/09/VCM-Q1Report_Full-Version-2.pdf.
25
Schneider, Lazarus, and Kollmuss, “Industrial N2O Projects Under the CDM: Adipic Acid - A Case of Carbon
Leakage?”26
Schneider, Lazarus, and Kollmuss.

11

Adipic Acid Production Issue Paper

Table 3. Example value of hypothetical CDM and JI projects adapted from the Stockholm Environmental Institute.27

Unit
Technology
Adipic Acid Production

CDM

Singlecatalytic/thermal
decomposition
Kiloton/year
150
Revenues from CERs or ERUs

JI
Redundant
catalytic/thermal
decomposition
150

Baseline emission factor

kg N2O/MT adipic acid

270

30

Project emission factor
Other emissions
CERs or ERUs
Price for CERs or ERUs

kg N2O/MT adipic acidtCO2e/MT adipic acid
CER or ERU/MT adipic acid
$

4
0.1
82.4
$18.070
0.1
9.2$18.07

Revenues from CERs or ERUs
CDM / JI Transaction Costs$/MT adipic acid$/CER or ERU$1,489
$0.79

$167
$0.53

Abatement Costs
Million $Million $/yearYears$11.12$1.39
20$18.07
$2.1
20

-

15%

15%

$/MT adipic acid

$1,402$128

Investment Costs
Operational Costs
Technical Lifetime
Required Return on
Investment
Net Profits from CDM or JI

MT = metric ton. All currencies were converted from EURs to 2010 U.S. Dollars with a conversion factor of 1.39. 28

SEI’s evaluation demonstrated a considerable difference in profit between CDM projects and JI projects($1,402 per metric ton adipic acid versus $128 per metric ton adipic acid), largely due to differences inbaseline setting. Again, these final differences in net profits were based on a comparably higher value for
CERs or ERUs that we would not expect in the U.S. voluntary market ($18 per unit versus $2.40 per unit,
650% higher).

3.2.2. Baseline Setting
As discussed earlier in the Issue Paper, a large amount of N2O emissions are already abated fromvoluntarily installed abatement technology. However, significant N2O emissions remain. A robust baseline
must only consider incremental emissions above and beyond the business-as-usual abatement levels.
Incremental reduction limitations could be achieved in two ways. First, a quantification protocol could set
a blanket average emissions reduction benchmark for which each facility could measure itself against.
Alternatively, the protocol could set baselines based on individual, facility-level historical emissions.

27

Schneider, Lazarus, and Kollmuss.
X-RATES, “Exchange Rate Average (Euro, US Dollar),” accessed July 4, 2019, https://www.xrates.com/average/?from=EUR&to=USD&amount=1&year=2010.
28

12

Adipic Acid Production Issue Paper

The blanket-average strategy is typical in several carbon policies; for example, the California cap-andtrade program utilizes sector-level emissions intensity benchmarks to determine free allowance allocation
for certain industries.29 This is also one strategy recommended by the SEI in their original evaluation of
the CDM market. However, recent global changes mean that this strategy is unsuitable for adipic acid
reduction projects; international baseline-setting data is insensitive to U.S.-specific technology andregulatory environment.
SEI originally argued that an international standard would level the playing field between facilities indifferent jurisdictions; however, price and carbon offset unit type (e.g., CDM credits vs. Reserve-issued
CRTs) have become extremely divergent. Facilities in the U.S. creating Reserve-issued CRTs will expect amuch different price compared to facilities generating CERs through the CDM. Although prices could
stabilize internationally in the long-term, we expect that the price of carbon offsets between jurisdictions
will remain divergent in the near future. For this reason, an apples-to-apples baseline does not achieve
the goal of international carbon market parity.
Therefore, a facility-level evaluation of historical emissions levels appears to be the most appropriate andstraightforward mechanism to set the baseline in the United States. Data for historical emissions levels
should be readily available because of GHG emissions reporting requirements under other regulations in
the U.S. We recommend setting the baseline emissions rate at the level achieved during the maximum
adipic acid production level from the past five years (percent N2O destroyed annually). This safeguard is
in-line with current practices in the Nitric Acid Protocol30
We do not believe any new adipic acid facilities will be built in the near future. If this were to occur, newfacilities could participate and generate carbon offsets with a default value baseline rather than a baseline
derived from historical emissions data. Any default baseline value would need to be carefully calculated
to acknowledge the well-established but voluntary nature of GHG abatement technology at existing adipic
acid plants. If it becomes more likely that an adipic acid facility may be built, the Reserve could review
options to calculate the default baseline and expand the Protocol.

3.2.3. Summary of Additionality
In the absence of regulatory requirements, there are no incentives to abate N2O emissions at adipic acidplants in the United States. Despite historical criticism of CERs generated under the CDM through at adipic
acid plants, we believe the risk of secondary effects in the U.S. would be extremely low; the incentive
structure does not exist to create non-additional credits because the value and volume of the credits will
be much lower. The Reserve’s protocol should ensure any CRTs generated would be incremental toexisting voluntary abatement levels by setting a baseline based on historical abatement levels. With these
protections, we believe future CRTs from an eligible adipic acid abatement project will be completely
additional.

29
30

17 California Code of Regulations § 95891
Climate Action Reserve, “Nitric Acid Production Project Protocol Version 2.2.”

13

Adipic Acid Production Issue Paper

4. Evaluation of Legal Requirements
Carbon offset credit must be for activities that are not currently required by regulation or covered underan existing carbon pricing regime. The following section evaluates existing or imminent regulations andregimes that could regulate N2O emissions from adipic acid plants.

4.1.

U.S. Regulations

Currently, there are no existing federal carbon pricing regulation (cap-and-trade or otherwise) in the
United States. No adipic acid plants are located in jurisdictions with such regimes (e.g., California). We do
not expect the current federal administration, headed by President Donald Trump, to pass any
comprehensive GHG regulations in the near term. There may be regulations in the future pending theoutcome of the 2020 presidential election; however, we believe it would be premature to speculate on
the nature, coverage, or likelihood of any federal carbon pricing systems post-2020. Should
comprehensive carbon regulations enter into-force during a Project crediting period, the Reserve would
follow standard procedures and allow any Project to finish its respective crediting period but be ineligible
for subsequent crediting period extensions.
Our regulatory review has determined that adipic acid plant N2O emissions will fall under the same
regulatory framework as nitric acid plant N2O emissions (GHG emissions from major stationary sources).
Accordingly, we are leveraging information from the Nitric Acid Protocol, which made the following
findings:
1. There are no existing federal, state, or local regulations that requires nitric acid (or adipic acid)plants to abate N2O emissions under typical circumstances.
2. If a facility triggers certain provisions under the Clean Air Act, they may be required to install some
GHG abatement equipment. If this occurs, projects may become ineligible for offsets.
The following section, adapted directly from the Nitric Acid Protocol with some alterations, reviews thecurrent status of GHG permitting under the Clean Air Act.

4.1.1. U.S EPA GHG Permitting Requirements under the Clean Air Act
There are some existing federal regulations that may impact adipic acid project GHG emissions.
Historically, the EPA regulated GHG emissions from major stationary sources under the Clean Air Act(“CAA”).31 Under this rule, commonly referred to as the “Tailoring Rule,” all existing stationary sources
emitting more than 100,000 tons (approximately 90,719 metric tons, “MT”) of CO2e emissions per year
were required to obtain Title V operating permits for GHG emissions. Additionally, facilities were required
to obtain Prevention of Significant Deterioration (“PSD”) permits that address GHG emissions for (1) new
source construction with emissions of 100,000 tons CO2e per year or more and (2) major facility

31

U.S. EPA published the final rulemaking, “Prevention of Significant Deterioration and Title V Greenhouse Gas
Tailoring Rule; Final Rule,” in the Federal Register 3 June 2010. The rulemaking is commonly referred to as the“Tailoring Rule,” and amended 40 CFR Parts 51, 52, 70, and 71. http://www.gpo.gov/fdsys/pkg/FR-2010-0603/pdf/2010-11974.pdf#page=1

14Adipic Acid Production Issue Paper

modifications resulting in GHG emission increases of 75,000 tons (approximately 68,000 MT) of CO 2e per
year or more.32
However, in 2014, the Supreme Court struck down the Title V provision of the Tailoring Rule33; therefore,
facilities are no longer required to report GHG emissions or control technology in their Title V permit. In
the ruling, the Supreme Court found that facilities may still be subject to reporting on PSD permits for
GHGs only if the facility is required to obtain a PSD permit for other, non-GHG pollutants.
When necessary, PSD permits for GHG emissions require an assessment of “best available control
technology” (BACT), with the permitting authority ultimately mandating installation of a selected BACT. It
is possible that future PSD permits may require installation of the same abatement technologies that are
currently being voluntarily deployed as part of carbon offset projects. By legally mandating thesetechnologies, PSD permit requirements may make them ineligible for carbon offsets because
implementation of these projects would no longer be voluntary.
In 2012, an INVISTA adipic acid plant in Victoria, Texas was required to install GHG abatement technology
following failure to procure appropriate PSD permits in 2004.34 Voluntarily-installed N2O abatement
projects should continue to be eligible for carbon offsets for the remainder of a project’s crediting
period(s). Verifiers will need to review PSD permits to ensure that projects are able to pass the Legal
Requirement Test.

4.2.

International Regulations

Although it may be possible to expand the protocol to Canada and Mexico in the future, both jurisdictions
are undergoing substantial reviews of their national GHG emissions regulations, which may make it
difficult to predict or evaluate the impact of emerging regulations on additionality and the legal
requirements test. The first version of the Reserve’s protocol will limit eligibility to the U.S.

5. Discussion of Protocol Composition
As previously discussed, the abatement measures for adipic acid production are extremely similar to thoseutilized in GHG abatement at nitric acid plants. Therefore, an Adipic Acid Protocol could be adapted
directly from the existing Reserve-approved Nitric Acid Protocol.35 We expect that the Reserve’s existing
best-practices for rigorous monitoring and quantification at nitric acid facilities to be similarly appropriate
at adipic acid facilities.
The following protocol composition review shall therefore discuss the existing Nitric Acid Protocol,
including any adaptive changes necessary for adipic acid facilities. In addition to the Nitric Acid Protocol,
32

United States Environmental Protection Agency, “PSD and Title V Permitting Guidance for Greenhouse Gases,”
March 2011, https://www.epa.gov/sites/production/files/2015-12/documents/ghgpermittingguidance.pdf.
33
Utility Air Regulatory Group v. Environmental Protection Agency et. al., No. 12–1146 (Supreme Court of theUnited States June 23, 2019).
34“Greenhouse Gas Prevention of Significant Deterioration (PSD) Permit Application, INVISTA S.a.r.l. Victoria
Plant,” March 12, 2012, https://archive.epa.gov/region6/6pd/air/pd-r/ghg/web/pdf/invista_app.pdf.
35
Climate Action Reserve, “Nitric Acid Production Project Protocol Version 2.2.”

15

Adipic Acid Production Issue Paper

the CDM hosts an adipic-acid specific protocol (AM0021)36, which will also be discussed to a lesser extent.
Although AM0021 is directly relevant to adipic acid abatement, we believe it is most appropriate to utilize
the existing methodologies that have already been approved by the Reserve.

5.1.

Project Scope and Boundaries

5.1.1. Facility Age Eligibility
The Nitric Acid Production Protocol defines the project as the installation and operation of a N2O
abatement technology at a single Nitric Acid Plant (“NAP”) that results in the reduction of N2O emissions
that would otherwise have been vented to the atmosphere. Projects are limited to existing, relocated or
upgraded NAPs that can provide historical production levels and operating conditions so the project canmeet the appropriate additionality constraints. We believe this project scope would be appropriate for
Adipic Acid Plants (“AAPs”).
The Reserve’s Nitric Acid Protocol limits applicability to NAPs constructed before December 2nd, 2009
(corresponding to the publish date of the first version of the protocol), while the CDM adipic acid
methodology limits applicability to AAPs that began commercial operation prior to December 31, 2004
(corresponding to the year prior to the methodology’s first publication). We do not believe that the Adipic
Acid Protocol should automatically make future facilities ineligible, because new facilities continue to lackany incentive to install control technology. However, new facilities would still be subject to the Legal
Requirements Test and may be ineligible if they must abate GHGs under their Title V permit. The firstversion of the Protocol may limit eligibility to existing plants because more research would be necessary
to establish an appropriate baseline for facilities with no emissions history.

5.1.2. Project Boundaries
The project boundary will be established in the protocol according to an evaluation of all sources, sinks
and reservoirs (SSRs). This will be presented as a “GHG Assessment Boundary” figure and a table of all
SSRs with details on each SSR, if they are included in or excluded from the project boundary, and if
excluded, why. This figure and table should represent and include all elements that could potentially be apart of the project.
We believe the Adipic Acid Protocol will have the following SSRs included in the project boundary:•••N2O from adipic acid production;
CO2 and/or CH4 hydrocarbons used as reducing agents and/or reheating the off gas (project only);
andCO2, CH4 and NO2 for reheating the off gas before entering the tertiary catalyst or NSCR (projectonly).

Individual projects should have the opportunity to evaluate the project-specific suite of SSRs and exclude
emissions if they can be proven to be de minimis or unchanged due to the project activity.

36

UNFCCC/CCNUCC, “Approved Baseline and Monitoring Methodology AM0021, ‘Baseline Methodology for
Decomposition of N2O from Existing Adipic Acid Production Plants’ Version 03.”16

Adipic Acid Production Issue Paper

We expect the following SSRs to be excluded from the Adipic Acid Protocol as in the Nitric Acid Protocol:•••

Non-N2O GHG emissions from adipic acid production (e.g., trace amounts of CO2, CH4);
Emissions from production, transport, and de-commissioning eligible technologies and catalysts;
andEmissions related to the production of hydrocarbons utilized in the project.

5.1.3. Geographical Boundaries
The first version of the adipic acid protocol would only apply to the United States. Expanding the protocol
to Canada and Mexico may be permissible given additional research.

5.2.

Quantifying GHG Emission Reductions

The amount of emissions reductions will be quantified by calculating the difference between the businessas usual baseline and the emissions after the technologies have been put in place (“Project Emissions”).

5.2.1. Standardized Baseline Calculations
Standardized baseline calculations could be adapted from the Nitric Acid Protocol and the CDM’s AM0021.
Baseline GHG emissions would be based on the existing quantity of N2O in the off gas following currently
installed N2O abatement.
In order to ensure the baseline is conservative and represents only the incremental emissions reduced
beyond historical levels, we also propose a Baseline Destruction Efficiency (“DE”) that accounts for thedestruction level prior to project implementation. As previously discussed in “Section 3.2.1 Baseline
Setting”, the DE would be the percent N2O emissions destroyed during the year with the highest
production levels in the past five years.
Additionally, the baseline will consider the average level of nitric acid (HNO3), which is an input in theadipic acid production process, being recovered and recycled in the five years prior to the project startdate. As discussed in Section 2.2, one potentially eligible technology would reduce virgin nitric acid input,
which should be included as a project emission reduction. We expect the recycling rate to be zero in thebaseline under most circumstances but recommend including a parameter to capture any facility-specificdeviations and practices.
In general, baseline emissions reductions would be calculated using the following equation, with eachparameter expanded and described in the full protocol:

17Adipic Acid Production Issue Paper

𝐵𝐸 = [ (𝑇𝐸𝑅𝑃,𝑁2 𝑂 × (1 − 𝐷𝐸)) + (HNO3 𝑅𝑎𝑡𝑖𝑜 × 𝐴𝐴𝑅𝑃 × 𝐸𝐹𝑁2𝑂 ) ] × 𝐺𝑊𝑃𝑁2𝑂
Where,

Units

𝐵𝐸

=

Baseline emissions during the reporting periodtCO2e

𝑇𝐸𝑅𝑃,𝑁2𝑂=

Measured total N2O emissions during the reporting period before any
emissions control treatment (e.g., destruction)

tN2O

𝐷𝐸

=

Baseline N2O destruction efficiency

𝐻𝑁𝑂3 𝑅𝑎𝑡𝑖𝑜=

Ratio of HNO3 to AA

tHNO3 / tAA

𝐸𝐹𝑁2𝑂

=

IPCC emission factor for N2O emissions per HNO3 production = 0.0025

tN2O / tHNO3

𝐺𝑊𝑃𝑁2𝑂=

Global warming potential of N2O

tCO2e / tN2O-

t = metric ton; AA = adipic acid

5.2.2. Project Emission Calculations
Project emissions come either from the off gas to an SCR de-NOx unit and any emissions that were notdestroyed by the eligible control technology. The project emissions will be characterized by the following
equation, with each parameter expanded and described in the full protocol
𝑃𝐸 = 𝑃𝐸𝑁2 𝑂 + 𝑃𝐸𝐻𝐶 + 𝑃𝐸𝐸𝐸
Where,

Units

𝑃𝐸

=

Project emissions during the reporting period

tCO2e

𝑃𝐸𝑁2𝑂

=

GHG emissions from N2O in the off gas during the reporting period

tCO2e

𝑃𝐸𝐻𝐶

=

GHG emissions from the use of hydrocarbons as a reducing agent or toreheat off gas during the reporting period

tCO2e

𝑃𝐸𝐸𝐸

=

GHG emissions from external energy used to reheat the off gas during
the reporting period

tCO2e

5.2.3. Leakage
No leakage adjustment is included in the Nitric Acid Protocol. The CDM AM0021 includes a final leakage
adjustment for steam produced outside of the project boundary and used at the AAP. Steam produced
within the project boundary would already be captured in baseline and project calculations. We believe
this adjustment will not be necessary in the U.S., as adipic acid plants rarely purchase steam.

6. Monitoring
Adipic acid facilities are already required to have a continuous emissions monitoring systems (“CEMS”)
for NOx emissions testing under the Clean Air Act (40 CFR, Part 60). As in the Nitric Acid Protocol, theproposed Adipic Acid Protocol will apply 40 CFR Part 75 for added quality assurance / quality control andwill implement CEMS upstream and downstream of N2O abatement units to achieve real-time destruction
efficiency data. CEMS are considered the industry standard for direct emissions monitoring and provide
18Adipic Acid Production Issue Paper

highly accurate and reliable data when installed and calibrated appropriately because they continuously
measure a specific source.37 CEMS are used in several Reserve-approved protocols; the Adipic Acid
Protocol will include the same standard rigorous calibration, accuracy testing, and quality
assurance/quality controls as the Nitric Acid Protocol.
As an example, the following items should be monitored and reported at the AAP:
•
•
•
•
•
•

Metric tons of adipic acid produced
Metric tons of nitric acid utilized and/or recycled
Volume flow rate in the off gas during the reporting period by the control unit
N2O concentration in the off gas
Operational hours in the reporting period
Methane use

The final Protocol should include a comprehensive list of all reporting parameters and monitoring
requirements based on detailed baseline and project calculations.

7. Environmental and Social Impacts
We do not expect an adipic acid GHG abatement project to have any direct or down-stream adverse
environmental or social impacts. As discussed earlier in the paper, the abatement technology would
neither increase secondary emissions, nor would it impact the production levels of the facility. The most
likely secondary emission to be impacted by a project, NOx, is already regulated under the CAA andfacilities would face legal penalties for increasing above their emissions limit. As such, we expect projects
to continue to run at a business-as-usual level, albeit with newly installed control technology.

37

This method is consistent with Approach 1 from the World Business Council for Sustainable Development andthe “A” rated approach from the U.S. Department of Energy.

19Adipic Acid Production Issue Paper

8. References
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Spalding-Fecher. “How Additional Is the Clean Development Mechanism? Analysis of the Application of
Current Tools and Proposed Alternatives.” Öko-Institut, March 2019.
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Climate Action Reserve. “Nitric Acid Production Project Protocol Version 2.2,” April 18, 2019.
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https://ieaghg.org/docs/General_Docs/Reports/PH3-29%20nitrous%20oxide.pdf.
Mainhardt, Heike, and Dina Kruger. “N2O Emissions from Adipic Acid and Nitric Acid Production.” Accessed June25, 2019. https://www.ipcc-nggip.iges.or.jp/public/gp/bgp/3_2_Adipic_Acid_Nitric_Acid_Production.pdf.
Reimer, R. A., C. S. Slaten, M. Seapan, M. W. Lower, and P. E. Tomlinson. “Abatement of N2O Emissions Producedin the Adipic Acid Industry.” Environmental Progress 13, no. 2 (1994): 134–37.
https://doi.org/10.1002/ep.670130217.
Schneider, Lambert, Michael Lazarus, and Anja Kollmuss. “Industrial N2O Projects Under the CDM: Adipic Acid - A
Case of Carbon Leakage?” Stockholm Environmental Institute, October 9, 2010, 23.
http://archive.carbonmarketwatch.org/wp-content/uploads/2010/10/sei-adipicacidleakage-9oct2010.pdf
UNFCCC/CCNUCC. “Approved Baseline and Monitoring Methodology AM0021, ‘Baseline Methodology for
Decomposition of N2O from Existing Adipic Acid Production Plants’ Version 03,” February 27, 2009.
https://cdm.unfccc.int/methodologies/DB/PC4EBQSJUB9IV2FS9TMQV8DFM3X6MZ.
United States Environmental Protection Agency. “Adipic Acid Production,” July 1994.
https://www3.epa.gov/ttn/chief/ap42/ch06/bgdocs/b06s02.pdf.
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X-RATES. “Exchange Rate Average (Euro, US Dollar).” Accessed July 4, 2019. https://www.xrates.com/average/?from=EUR&to=USD&amount=1&year=2010.

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