Infrastructure for asustainable future
Summary

Lydia Slobodian & Lorena Martínez HernándezSEROVA
926 C St NE
Washington DC 20002
United States of America

Cover image source: (Quevedo Gutiérrez et al., 2013)

Introduction
The next twenty years will represent an unprecedented demand for new infrastructure. As
developing countries increasingly demand modern infrastructure for growing, urbanizing
and industrializing populations, developed countries deal with aging infrastructure indesperate need of replacement. The expected investment in new infrastructure between
now and 2040 is higher than the current value of all of the infrastructure in the world(Thacker et al., 2019). This opportunity is a double-edged sword: infrastructure is an
expensive and long term investment. Badly developed infrastructure is difficult to replace,and can create debt lasting generations. Unsustainable patterns of development can belocked in by infrastructure that lasts decades.
Climate change will have a significant impact on infrastructure. Existing energy andtransport infrastructure will produce emissions far exceeding the targets agreed in the
Paris Agreement unless it is abandoned or repurposed before the end of its life (Thacker etal., 2019). Climate change will create conditions that current infrastructure is not designed
to withstand and uncertainty that government policies and safety standards are not able toaddress (Chester, Underwood and Samaras, 2020). Adapting infrastructure to climatechange will require more than strengthening and reinforcing current designs; there willneed to be a change in thinking about how infrastructure is imagined and used (Shortridge
and Camp, 2019). The purpose of this study is to examine case studies of proposed or
emerging infrastructure technologies to evaluate how they can contribute to climatechange mitigation or adaptation in the coming years.
Case studies were selected on the basis of five predefined search criteria:
1. Infrastructure: does the case study involve significant built infrastructure?
2. Cross-cutting ideas: does the case study take advantage of opportunity,
encompass long term vision or show leapfrogging or repurposing potential?
3. Internationality: does the case study promote transboundary cooperation or
reduce the risk of conflict?
4. Stage of development: is the case study based on or developed from existing
technology?
5. Representativeness: do the case studies represent a range of infrastructure
sectors (adaptation, agriculture, communications, energy)?
From an initial list of ten cases, five were selected for evaluation: floating cities,
multipurpose platforms, hybrid coastal resilience, smart undersea cables and gravity
storage. The study authors assessed each of these case studies through a review ofpublished literature and reports. They evaluated case studies in terms of three factors: 1)
climate change adaptation/mitigation potential; 2) feasibility and cost; and 3) environmental
and social impact. Each of these factors was given a score of 1-5, where 1 reflects thelowest potential and 5 the highest potential. Table 1 presents the criteria used in
evaluation. In addition, each score is given a certainty ranking from low certainty to highcertainty, representing the evidence behind the evaluation.

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Adaptation/mitigation
potential

Feasibility andcost

Environmental andsocial impact

Potential for adaptation: risk
reduction, resilience
improvement, planning,monitoring and evaluation

Technological feasibility:
stage of development,
results of trials, evidence
from implementation

Environmental/social
negative impacts:
ecosystem degradation,
pollution, displacement,
conflict, health impact

Potential for mitigation:
carbon sequestration, demand
reduction, shift to clean energy

Cost: development,
construction, maintenancecosts relative to benefit,
compared to alternatives

Environmental/social
co-benefits: ecosystemservices, valuable species

No real potential for
adaptation/mitigation

Not technologicallyfeasible now or in the near
futureSignificant, negative andunavoidable environmental
and social impact

Climate benefits outweighed byemissions or other climate
impacts

Financial costs areprohibitive

No co-benefits

Small potential for
adaptation/mitigation

Needs significant technicaldevelopment

Some unavoidable negativeenvironmental and social
impacts

Climate impacts cancel much
(but not all) of the benefit

Financial costs are more
expensive thanalternatives

Moderate potential for
adaptation/mitigation

Technologically feasible,
may need testing

Negative impacts low or
outweighed by benefits

Costs comparable toalternative technologies

Score
1

2

3

Minimal co-benefits
Negativeenvironmental/social impacts
can be mitigated orcompensatedSome co-benefits

4

5

Significant potential for
adaptation/mitigation

Technology ready for
deployment

Minimal negativeenvironmental/social impact

Any impacts strongly
outweighed by benefits

Costs lower than some(but not all) alternatives

Some co-benefits

Transformative potential for
adaptation/mitigation

Technology works betterand at a lower cost than
any alternative

Minimal negativeenvironmental/social impact

No negative climate impacts

Significant co-benefits

Table 1: Criteria for evaluating case studies

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Floating cities
Over the last 70 years extensive efforts have been put on research and development oftechnologies to build very large floating structures (VLFS) for a wide range of applications
such as airports, military bases, offshore energy plants and, more recently, urban
settlements (Wang and Tay, 2011).
VLFS are artificially man-made floating parcels on the sea. They may be categorized into
two types according to their geometry: 1) pontoon; and 2) semi-submersible (Wang andTay, 2011). The pontoon-type has a structure similar to a steel ship hull and is used incalm waters, close to the coast with very low or no waves. They have mooring or
anchoring facilities to keep the floating structure on site and usually are connected to landthrough a bridge or a floating road. The Semi-submersible type has a platform raised
above sea level using column tubes, is suitable for deployment in high seas with large
waves, and is mobile (not anchored) (Lamas-Pardo, Iglesias and Carral, 2015).
Depending on the VLFS type, they can range from 1,000m to 10,000m, they can displacefrom 106 tons to 107 tons, and they can last from 50 to 100 years.

FactorCombinedscores

Score

Comments

4
Low certainty

Though there is little evidence linking floating cities tomitigation, they may have significant adaptation value
for certain locations, particularly as a response toflooding of low-lying urban areas, as long as they canbe designed to withstand extreme climate events.

2
Moderate
certainty

Significant development challenges remain before
floating cities can be considered a viable solution tosea level rise. Coastal pontoon type VLFS havelower maintenance and manufacturing costs, but still
range between $5,000 million and $15,000 million.

3
Low certainty

While some studies suggest little environmental
impact from floating cities themselves, there has been
little investigation of the impact of the additional
protective infrastructure necessary to make floating
cities possible. Floating cities could provide social
benefits by alleviating the need for massive relocationof populations.

9
Low certainty

This technology has medium potential for addressing
climate change with minimal or avoided negativeenvironmental impacts.
The lack of application of VLFS to urban purposes
indicates that there is a considerable need to conduct
further research before sound conclusions on theirfeasibility and environmental and social impacts canbe made.

4

Floating platforms for food and energy production
Continued population growth and corresponding increasing demands for food and energy
has boosted commercial interests in the ocean as well as research on floating
infrastructures that integrate aquaculture and energy production (Aryai et al., 2021).
Commonly, these structures are framed as multi-purpose floating platforms (MPFP), which
can have very diverse designs, combinations and purposes, and can operate in shallow
waters as well as open seas. The economic, environmental and technical feasibility iscase-specific and cannot be easily generalized.
Smart floating farms (SFF) are one type of MPFP that integrate solar energy, hydroponics
and aquaculture on a single multi-storage floating platform (www.smartfloatingfarms.com).
SFF consists of pontoons that support a three-floor building/structure. At the lower level, a
recirculating aquaculture system (RAS) is installed to produce fish (Bregnballe, 2015). On
the second floor, a hydroponics plant is operated, where fish excrement extracted from the
RAS is used as nutrients for crop production. Finally, on the rooftop, solar panels are
installed to supply the energy needs of the aquaculture and hydroponics facilities. SFF are
designed for shallow waters, near the shore, using mooring systems.

FactorCombined
score

Score

Comments

3
Moderate
certainty

SFF alone has low to moderate adaptation andmitigation potential from improving agricultural
efficiency and reducing land use, but some forms of
MPFP that include renewable energy have a higher
potential.

3
Low certainty

There is still a need for significant research anddevelopment before MPFP is shown to be feasible, but
approaches that have been assessed show promise to
be cost effective. There are many variables that factor
into feasibility: whether existing platforms are being
repurposed, the location of the platform and the
purposes incorporated.

3
Moderate
certainty

While environmental risks vary among applications, forsome applications there is a chance of significant
adverse impacts on the marine environment and local
fishers. Where RAS is used, some impacts can be
mitigated.

9
Moderate
certainty

This technology is still in its infancy and there is needfor research to confirm its technical and economic
feasibility, as well as the appropriate combinations ofrenewable energy and aquaculture systems to mitigate
potential environmental risks or even produce a
positive effect on the marine ecosystem. It also shows
the need to work out regulatory questions related topermitting associated to the multiple purposes
integrated in the platforms.

5Hybrid coastal resilience approaches
Climate related storm surges and sea level rise pose a significant threat to coastal
communities, which make up a large part of the global population. Hard infrastructure
responses, such as seawalls, dykes and breakwaters are expensive and often
environmentally damaging, while nature-based solutions using ecosystem restoration may
not be feasible or sufficient in all cases. This has led to increasing interest in hybrid
approaches, which combine hard infrastructure with green approaches and components(Sutton-Grier, Wowk and Bamford, 2015).
Hybrid approaches exist along a spectrum between grey and green infrastructure, and canencompass:
1. hard infrastructure designed to imitate or support ecosystem functions andconnectivity, such as seawalls designed to provide habitat for living organisms;
2. a combination of hard infrastructure and living ecosystems, such as salt marshes
cultivated in front of seawalls; and3. use of hard infrastructure to seed, frame or instigate growth or restoration ofprotective ecosystems, such as use of artificial structures to attract reef-building
species.
FactorScore
3Moderate
certainty

5
Moderate
certainty

5
Moderate
certainty

Combined score

13
Moderate
certainty

Comments
Hybrid infrastructure has the potential to provide greater
coastal protection than either natural or built
infrastructure alone, and can provide limited mitigation
through incorporation of carbon sinks. It is difficult toquantify the relative effectiveness of hybrid infrastructure
due to a lack of comprehensive data.
The cost of hybrid approaches varies with location, but
is typically less than the cost of achieving equivalent
protection with grey infrastructure alone (estimated at$70 billion/year). Maintenance costs are lower due tothe ability to self-repair of the living component of hybrid
infrastructure. Notwithstanding, there is little statistical
data on the relative costs and benefits of hybrid
infrastructure compared to hard or soft infrastructure.
Hybrid infrastructure is designed to mitigate many of theenvironmental impacts created by hard infrastructure. It
can also create social and economic co-benefits in theform of recreational opportunities, water filtration andincreased fish populations. However, carefulconsideration and design must be taken to achievethese environmental and social effects.
Hybrid coastal resilience infrastructure are among themost promising technologies for achieving climate
adaptation benefits at lower cost than existingalternatives and with several environmental co-benefits.
Due to their relatively recent development, there is anurgent need for additional research, particularly on how
the interaction between hard and soft components
contributes to effectiveness and the relative costs andbenefits compared to hard or soft infrastructure.

6Smart undersea cables
The global lack of data on deep ocean processes impedes accurate modeling of climate
events and trends. Obtaining high quality data, particularly from the deep ocean and thepoles, can be difficult and expensive. One proposed solution is incorporating sensors into
existing telecommunication cable networks to scale up ocean observation at a reasonable
cost.
Cables have been used for ocean monitoring for decades: in the 1990s undersea cables
were used to detect earthquakes and tsunamis off Japan; since then several countries
have created dedicated cabled observatories such as the VENUS and NEPTUNE
observatories in Canada, DONET and S-net in Japan and the Ocean Observatories
Initiative in the US (Baggeroer et al., 2018). In 2012, a UN Joint Task Force (JTF) wasestablished to consider options for scaling up ocean observation by taking advantage ofthe extensive undersea telecommunications cable infrastructure. The JTF has developed
the concept of Science Monitoring and Reliable Telecommunications (SMART) cables,
which integrate sensors for monitoring pressure, temperature and seismic activity into newtelecommunications cables. It is working on a demonstration project, to incorporate
sensors with short-distance submarine cables in the South Pacific, with support from the
ADB (Howe et al., 2019).

Factor

Score

Comments

4
High certainty

Smart cables have significant potential to generate
data relevant for disaster risk reduction (DRR), CO2
processes in the oceans and essential ocean
variables. This information is essential for adaptation
planning and for building more accurate early warning
systems.
SMART cables could be included in most routes in
the near future (5 to 10 years). The yearly cost of
SMART cables deployment at global scale ismoderate. However, there are still some technicaland legal questions to be solved before SMART
cables become a reality.
There is little information on the potential
environmental and social impact of SMART cables.
Based on the impacts of existing communications
cables, it seems unlikely that the additional sensors
would significantly increase the impact. This
technology will create significant environmental
co-benefits by contributing to knowledge andunderstanding of deep oceans and its biodiversity.
Smart undersea cables have a significant potential for
adaptation to climate change, they are almost readyfor deployment and they could provide more accurate
and difficult to access data than other technologies atcomparable costs, with minimal foreseeable negativeenvironmental and social impacts and positiveenvironmental co-benefits.

4
High certainty

4
High certainty

Combinedscore

12
High certainty

7Gravity storage
Gravity storage has been suggested as an efficient, cost-effective, low-impact means ofincreasing available energy storage and facilitating scaling up of renewable energy. The
most established form of gravity storage, pumped hydro storage (PHS), is a maturetechnology, and currently makes up 98% of global energy storage (Mongird et al., 2019). It
functions by pumping water from a lower reservoir to a higher one using excess energy
during times of high supply or low demand, and then releasing the water to power a turbine
and generate energy when it is needed.
New innovations in gravity storage take different forms intended to be more convenient,cheaper, or more environmentally friendly than conventional PHS. Underground pumped
hydro storage (UPHS) systems are based on the same principle as PHS, but locate one orboth reservoirs underground. To avoid the cost and impacts of excavation, UPHS can takeadvantage of existing infrastructure, such as abandoned mine shafts. UPHS projects havebeen proposed in deep gold mines in South Africa, old slate mines in Belgium and closed
coal mines in Spain and Germany (Menéndez, Fernández-Oro and Loredo, 2020). Other
proposed gravity storage systems use heavy weights or pistons in underground shafts,
which can be suspended by cables (dry gravity storage) or float in water (hydraulic gravity
storage) (Botha and Kamper, 2019).
FactorScore
5High certainty

4
High certainty

4
Moderate
certainty

Combinedscore

13
High certainty

Comments
Energy storage will be essential to scaling up
renewable energy generation by capturing excess
power, smoothing out fluctuations in energy supply
and respond to peaks in demand. Gravity storagealone will not be enough to meet the green economy
demands, but there is significant evidence that thistechnology can play a role in reducing use of fossil
fuels in energy production at the level of the grid. It
could also support adaptation by increasing resilienceof the electric grid in case of extreme weather events.
PHS is a relatively efficient storage option (70-85%)
with a short response time, long lifetime and low
operation and maintenance costs. It requires a highupfront investment, but it has a very low lifetime cost
per unit of electricity compared to other options.
New types of PHS have minimal environmental andsocial impact, particularly compared to impacts ofalternatives, like lithium-ion batteries. Modern PHS
systems use a closed loop minimizing direct impact
on aquatic ecology. UPHS may have even a lower
impact if they repurpose existing excavations.
Gravity storage has transformative potential in termsof climate change mitigation. The technology has
been tested and is ready for deployment at costs
lower than existing alternatives. Environmental andsocial impacts are significantly lower thanalternatives.

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Summary
Each of the infrastructure technologies assessed in this report has a potential role inclimate change mitigation and adaptation. It is difficult to directly compare them because
they are designed to serve different purposes and achieve different goals. Where hybrid
resilience and smart cables can be seen as an important and beneficial modifications ofexisting infrastructure, multipurpose platforms and floating cities are ambitious newtechnologies that may or may not serve a purpose in a climate change world.
Different technologies can work together. Multipurpose floating platforms can be designed
to incorporate hybrid elements of grey and green infrastructure, and can be integrated in agrid with gravity storage options to maximize efficient use of wind or solar energy output.
Investment in research and technological innovation would be helpful for each of the fivetechnologies. For those that are ready to deploy, like hybrid resilience, additional research
can help build the case for adoption. For gravity storage and smart cables, research andtesting is needed to enable deployment in the short term. For floating cities andmultipurpose platforms additional investment could bring these ideas into the world ofreality and ensure that they are sustainable and effective.
CombinedscoresFloating cities

4

2

3

9

Low certainty

Moderate
certainty

Low certainty

Low certainty

Multipurpose
platforms

3

3

3

9

Moderate
certainty

Low certainty

Moderate
certainty

Moderate
certainty

Hybridresilience

4

5

4

13

Moderate
certainty

Moderate
certainty

Moderate
certainty

Moderate
certainty

Smart cables

4

4

4

12

High certainty

High certainty

High certainty

High certainty

5

4

4

13

High certainty

High certainty

Moderate
certainty

High certainty

Gravitystorage9References
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