Crunching the numbers on floating solar - Why Use Cleantech ...
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Design and Build Technical Briefing
Crunching the numbers
on floating solar
Floating PV | A major new study
published by the World Bank has
underlined the scale of the opportunity
represented by floating solar systems,
but highlighted issues of cost,
bankability and regulation still
facing this emerging branch
of the solar industry. Sara
Verbruggen reports on
the first serious piece of
heavyweight analysis
of the prospects for
floating solar
Credit: Lightsource BP
F
loating solar has global potential, with estimate puts floating solar’s overall global Floating solar Therefore, this annual figure may not
cumulative installations exceeding potential, based on available man-made capacity now materialise immediately in 2018 or 2019,
exceeds 1GW
1GW today, according to an upcoming water surfaces, in excess of 400GW. Since but is likely thereafter.”
worldwide, but
floating solar market report, ‘Where Sun the first floating PV system was built in has significantly
Meets Water’, written by the Solar Energy 2007 in Aichi, Japan, the market has grown greater poten- Costs and project structuring
Research Institute of Singapore (SERIS) at with projects increasing in size and more tial if issues Calculated on a pre-tax basis, the levelised
around cost and
the National University of Singapore and countries installing these types of renew- cost of electricity (LCOE) for a generic
bankability can
published by the World Bank and the Inter- able energy plants. be surmounted 50MW floating PV system does not differ
national Finance Corporation. Around 500MW was installed in 2017 significantly from that of a ground-mounted
That said, investment costs are about and 2018, much of it in China by making system.
US$0.10 per watt higher for floating use of flooded mine sites. Many floating The higher initial capital expenditures
solar projects, compared with equivalent solar projects are being developed or of the floating system are balanced by a
ground-mounted plants, providing oppor- under feasibility studies in many different higher expected energy yield, from the
tunities for collaboration between the parts of the world. cooling effects of the close proximity of
solar industry and other sectors in order to SERIS’ senior financial advisor Celine cold water. This is conservatively estimated
bring down costs and deliver large-scale Paton says: “If they all materialise, then at 5%, but potentially could be as high as
projects. yes we could see such annual growth of 10-15% in hot climates.
400-500MW taking place. However, the
Demand outlook development and realisation of these Capital expenditure (capex)
According to the report,, a summary of projects also depends on many factors, The main difference in investment costs
which was published in early November which are not always controlled by the when comparing floating PV with a
as the first in a series planned by the owners/developers: politics, environmen- ground-mounted PV plant of similar size
World Bank and SERIS, a conservative tal aspects, but also appetite from banks. is in the floating structure and the related
46 | December 2018 | www.pv-tech.org
Technical Briefing Design and Build
Floating PV Ground-Mounted PV
19% 21%
34% Modules 40%
Inverters
Mounting System
BOS
18% Design, Construction, T&C 13%
Credit World Bank/SERIS
8%
16%
21% 10%
Source: Authors’ compilation based on 2018 data received from industry. Notes: BOS = balance of system, T&C = testing and commissioning.
Figure 1: Floating versus ground-mounted 50MW PV investment cost breakdown (numbers indicative only)
anchoring and mooring system. These numbers on the main average cost per A breakdown of the main capex cost
are highly site-specific, according to the component for a hypothetical 50MW float- components assumed for a hypothetical
report’s authors. At this early stage in the ing PV system on a freshwater reservoir, 50MW solar PV installation, comparing
market’s development, lack of experience based inland. In addition, the theoretical floating to ground-mounted systems, both
as well as available data makes it very site presents no particular complexity. For of which are fixed tilt, at the same location
difficult to provide an “average” cost figure instance, the maximum depth level is 10m is shown in Figure 1.
with confidence. and there is minimal water level variation. Standard module and inverter costs are
Cables, a balance of plant (BoP) element The cost component assumptions used assumed identical for both technologies.
and cost for all types of PV installations, in the report’s chapter on cost analysis are Mounting system, including floating struc-
differ for floating solar projects. Using based on SERIS’ experience, investigations ture, anchoring and mooring for floating
direct current (DC) – in some cases and guidance from solar PV equipment PV and BoP costs are significantly higher
submarine – electric cables with additional suppliers, engineering, procurement and for floating solar projects as opposed to
insulation and shielding properties to construction contractors and developers. ground-mounted.
protect against moisture degradation, The authors stress the figures represent On a per watt-peak basis, industry
potentially adds a premium to the capex estimations and need to be adjusted once experience has shown that floating PV
of a floating solar plant compared with a the design and location of a specific float- capital expenditure to date tends to remain
ground-mounted PV system. ing PV project is determined and as more US$0.10 higher than ground-mounted PV
In capex cost modelling, the report’s cost figures become available from the projects under similar conditions.
authors have tried to make reasonable completion of more and more large-scale Improved economies of scale and
assumptions in terms of crunching the floating PV systems across the world. competition between vendors will begin to
UK—0.2 MW Sheeplands (2014) 1.14
Japan—2 MW Shiroishi Saga (2015) 3.12
Portugal—0.2 MW EDP Hydro (2016) 2.31
UK—6.3 MW Queen Elizabeth II (2016) 1.22
China—20 MW Anhui Xinyi (2016) 1.48
Japan—2.4 MW Noma Ike (2017) 2.93
China—40 MW Anhui Sungrow (2017) 1.13
India—0.5 MW Kerala (2017) 2.84
Japan—1.5 MW Mita Kannabe (2017) 2.93
Japan—13.7 MW Yamakura Dam (2018) 0.97
India—2 MW Andhra Pradesh (2018) 0.92
China—150 MW Three Gorges (2018) 0.99
Credit World Bank/SERIS
India—5 MW West Bengal Auction Lowest Price (2018) India—5 MW West 0.83
Bengal Auction Avg Price (2018) 1.14
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
0.8 1.2 USD/Wp
Figure 2. Investment costs of floating PV in 2014–2018 (realised and auction results)
www.pv-tech.org | December 2018 | 47
ADVERTORIAL
Floating solar industry turns to
Seaflex for its mooring expertise
Many investors, project managers, engineers, and product example, different environmental conditions like water levels and
manufacturers are concerned with the longevity of individual wind from two identical 2.5 MW facilities can have very different
components of floating PV systems. The LCOE generally designs and costs associated with the mooring. Another factor
revolves around a lifespan of 20-25 years for such floating PV can be the proximity of the solar panels and floats to the shores
projects. How does Seaflex tackle the challenge of longevity of the water source. A system located in the middle of a body
and make ownership cost effective? of water is moored differently than one where all four sides are
Our approach to a 20-year-plus longevity for our mooring close to the shores.
systems comes from several factors. First being that we have a Factors such as these are why we caution designers and
20-year warranty on our products and mooring solutions. We can engineers not to guess about the mooring solution based
offer this because we have over 30 years’ experience designing on sizes or designs of other seemingly similar floating solar
and building marinas using the Seaflex mooring systems. We applications.
currently have Seaflex in marinas that are over 30 years old, so
we know from real-life experience that our products, materials Why is using Seaflex versus other mooring technologies
and designs last a long time. beneficial for floating solar applications?
We have adapted our range of Seaflex products and mooring The use of metal cable and chain in mooring floating solar
designs to be utilised in the floating solar segment. We have projects is one type of solution that comes with many drawbacks
numerous different mooring designs and products that can and potential devastating failures. We have seen such real-life
handle a wide variety of environmental factors such as water failures and therefore can comment on the design and material
levels from zero meters to hundreds of meters deep. We also inadequacies.
have existing floating solar projects that have survived typhoons Seaflex offers an elastic solution that unlike metal cable and
without failure. So, we can say from real-world experience that chain provides a dampening effect that neutralises shocks
Seaflex, installed on floating solar applications, can also withstand (or peak load effect) to both the floats and solar panels from
extreme wind conditions as well. Additionally, our mooring wave and wind forces. This is beneficial from both a safety and
products are compatible with every floating solar panel float, durability standpoint in that the possibility of potential damage
which allows for seamless integration and helps to increase the over a 20-year period is minimised, saving material replacement
lifespan of the floats and solar panels. and labour costs. It should also be said that the usage of piles as
Since Seaflex products only require routine inspections and a mooring solution has the same risks as cables in that shocks
do not require maintenance, we provide a much lower cost of and peak loads are not at all dampened and therefore can also
ownership over the lifespan of our applications. create a total failure in storm conditions.
Additionally, Seaflex products utilise very little metal and even
What should designers and engineers be careful to consider offer a titanium hybrid option to drastically limit corrosion and
when looking at mooring solutions for floating solar material degradation. Another benefit of our elastic mooring
applications? solution is that Seaflex can handle water level variations from very
One misconception that many designers and engineers have small to very large (+50 meters!) This would not be possible using
when considering the mooring aspect of the floating solar the metal cable, chain or pile solutions.
application is the correlation between the size (in megawatts)
of the system and how much in terms of cost and quantity of If you have questions about this article or other questions
mooring is needed. Unfortunately, the relationship is not linear regarding floating solar applications, please do not hesitate to
and is somewhat complex to describe. contact us at info@seaflex.net
There are many factors which can change the quantity, For information on Seaflex products, services and reference
composition of materials and design of the mooring system. For material please visit our website at www.seaflex.net
48 | December 2018 | www.pv-tech.org
Anchoring innovative KERALA, INDIA
floating applications Adtech Systems Limited
is our passion!
Shown above is a 0.5 MW floating
solar park in India, the SEAFLEX
holding it in place manages their 20+
SEAFLEX is the flexible mooring solution meter water level variation.
that has been securing floating applica -
tions world-wide since 1981. The system
can be used regardless of water depth,
How Seaflex mooring works
while handling large water level variations,
strong currents and storm conditions. Floating application Buoy
We are thrilled to follow the development in the
groundbreaking floating renewable energy sector.
Seaflex Rope
Anchoring such innovative applications couldn’t be Seaflex
a better fit for us, since achieving longevity while
taking environmental responsibility have always
been cornerstones in the creation and develop-
ment of the SEAFLEX mooring system.
SEAFLEX is used whenever there is a need to
anchor something floating, such as commer-
cial marinas, wave attenuators, floating solar
parks or wave energy converters. The
system expands and retracts with each
tide and wave, taking on and
dampening the forces
year after year.
GEUMJEON, KOREA, Nemoeng Co.
This pictured 2MW floating solar power
plant produces electricity that can be
used by 660 households at the same time. Contact us
SEAFLEX is used to secure both
info@seaflex.net
110 x 100 m platforms.
See more at
www.seaflex.netDesign and Build Technical Briefing
Ground-mounted PV Floating PV of floating PV systems under similar condi-
(fixed tilt) (fixed tilt) tions is estimated to increase by 5% in
the conservative scenario and 10% in the
Electricity produced (first year), GWh 75.8 79.6
Increase in performance from ground-mounted fixed tilt 5% optimistic scenario.
In the conservative scenario (+5% PR),
Credit: World Bank/SERIS
LCOE (U.S. cents/kWh)
the LCoE of a floating PV system is 8-9%
at 7% discount rate (base case) 5.0 5.6 higher than the LCOE of a ground-mount-
at 8% discount rate 5.2 5.7 ed PV system. In the optimistic scenario
at 10% discount rate 5.4 6.0 (+10% PR), the floating PV LCOE is only
3-4% higher than the LCOE of a ground-
Source: Authors’ compilation.
Note: GWh = gigawatt-hour; kWh = kilowatt-hour; LCOE = levelized cost of electricity; MWp = megawatt-peak; PV = photovoltaic mounted PV system.
In time, say the report’s authors, this
Comparing the levelised cost of electricity from a 50MWp floating with that from a ground-based PV system
difference is likely to reduce, become
zero, or may even reverse with an
System size (MWp) Business model Ownership Financing structure increasing installed base and anticipated
≤5 Self-generation Commercial and Pure equity and/or corporate financing cost reductions for floating PV instal-
industrial companies (or “on balance sheet” financing). Owner lations as volumes go up. The installed
would typically be an energy-intensive
capacity today is much smaller in relation
commercial or industrial company
with ponds, lakes, or reservoirs on its to ground-mounted PV systems across
premises and willing to install a floating the world.
solar system for its own use.
>5 Power sold to the Independent power Mix of debt and equity (typically 80:20); Bankability
grid producers and public on balance sheet or non-recourse According to the report, from an investor’s
utilities project finance. The latter is still rare,
perspective, more traction needs to be
however, because such project finance
Credit World Bank/SERIS
structures make sense only for projects gained in terms of bankability of floating
of a certain size (generally larger than solar systems, which will come over time,
10 MWp). Future large projects will likely when durability and reliability have been
have financing structures similar to
proven in real-world installations.
the ones used for utility-scale ground-
mounted PV projects. In this early phase of the market, floating
Source: Authors’ compilation. solar PV plants are deemed to have more
Financing structure versus size of floating solar system risks than conventional land-based instal-
lations. They include a lack of experience
with long-term reliability of system compo-
drive down float costs, lowering capex. Levelised cost of energy (LCOE) nents, particularly modules, cables and
Module costs are a slightly smaller Data from across the world shows that inverters, under permanent high-humidity
proportion of overall investment costs floating PV systems have a higher energy conditions. Paton says: “This remains one of
for a 50MW floating PV project, at 34%, yield compared with ground-mounted PV the main barriers at this stage.”
versus 40% for a 50MW ground-mounted systems under similar conditions. According to the report’s authors, when
solar plant. Irradiance level and ambient tempera- banks are considering investing in projects,
Design and construction costs and tures relating to the climate where a they are looking at the creditworthiness of
inverter costs see little variation, though project is located are an even more sensi- every counterparty. This will stand in the
are proportionally slightly less for a float- tive variable for calculating the energy favour of big, established solar developers
ing PV farm than for a ground-mount PV yield and, therefore, the LCOE of floating and EPC companies. In many cases these
installation. solar plants. types of businesses also have the funds for
Together, mounting system, which Preliminary results show that in on-balance sheet financing that charac-
include floats, and BoP costs are higher as hotter climates the energy yield gain of terises how projects have tended to be
a proportion of capex for a floating solar a floating PV plant when compared to financed and funded in the initial stages
project, compared with a ground-mounted ground-mounted technology is higher of the conventional, land-based, solar PV
one. For floating PV, BoP and mounting than in temperate climates thanks to the market’s development.
system costs account for 39% of total cooling effect on PV modules, improving “That said, we are seeing a mix of
capex investment, compared with 29% for their efficiency. models at this stage, especially when
ground-mounted PV. However, the authors advise that more systems are not too large and funded
Regionally floating PV capex varies studies should be done to verify this asser- with equity or corporate – balance sheet
just as it does for ground-mounted PV, tion and to more accurately quantify the – financing, or a mix of both, from the
market by market. As reflected in Figure correlation between energy yield gains owner,” Paton says.
2, Japan remains a region with relatively and various climates. Traditional solar developers with experi-
high system prices, while China and In the report, representative ‘average’ ence of developing large rooftop and
India achieve much lower prices, a trend P50 global horizontal irradiance and ground-mounted PV projects are diversify-
reflected in these countries’ ground- performance ratio figures for ground- ing into floating PV. Examples include
mounted and rooftop solar system prices, mounted PV have been estimated for each Lightsource BP, Canadian Solar, Sunseap
in the context of the global average. climate zone. The performance ratio (PR) and Cleantech Solar. Some of them are
50 | December 2018 | www.pv-tech.orgTechnical Briefing Design and Build
doing the EPC themselves or are outsourc- Oliver Knight at the World Bank’s compensation rate adder. A renewable
ing it to other companies. Energy Sector Management Assistance energy certificate (REC) mechanism has
According to Paton: “Most of the time Programme (ESMAP) division says: also been implemented in South Korea,
the company providing the float structure “Floating solar is more straightforward to which favours floating solar over ground-
will be involved in overall plant design, EPC develop in many cases, since large bodies mounted plants. In countries in Southeast
and operations and maintenance (O&M) of manmade water tend to be under Asia, such as Vietnam, floating PV projects
support; thereby ‘training’ the developer to public or government ownership, such as benefit from the same FiT as ground-
gain skills in floating PV. The float supplier hydropower dam reservoirs, for example. mounted PV, which was also the case in
therefore has a key role to play in the If you have one owner then the project Japan, though FiTs have been removed for
development and construction of these is simpler to develop rather than dealing large projects.
plants.” What is needed, say the report’s authors,
In certain jurisdictions float suppliers are more empirical studies to determine
are forming partnerships with developers, “Floating solar is more straight- the exact advantages of floating PV
such as Ciel & Terre, a French company that systems in various climates or how to
has commercialised a floating PV mount-
forward to develop in many create beneficial hybrid business models,
ing system and is working with developers cases, since large bodies with hydropower plants, for example.
and EPCs in France, the UK, the US, Colum- “Floating PV is still a new applica-
bia and other markets. of manmade water tend to tion and there will be a need to address
The market has also provided opportu- it specifically through regulations and
nities for new developers, which are defin-
be under public or govern- policies, especially with regards to permit-
ing their business or service as a one-stop ment ownership. If you have ting, licensing and eventually minimum
shop floating PV solution provider. “This is quality standards,” says Paton.
in the case of maritime companies looking one owner then the project is Knight adds: “There may be a need for
to bring their skills to floating offshore enhanced monitoring for a country’s first
solar projects in marine or nearshore
simpler rather than dealing with few floating solar projects, particularly in
environments, which are more compli- several” terms of gathering evidence of the environ-
cated to do than floating solar systems on mental impacts of such projects on fish and
reservoirs,” Paton says. other aquatic life. This would be a good
According to the report, in order to with several. In many cases the owners candidate for concessional or grant financ-
design, build, commission and operate want these assets to be used.” ing, for example using climate finance.”
floating solar PV plants that are bankable Both Paton and Knight agree that As the market is at an early stage the
and are able to produce competitive, clean subsidy regimes for floating solar – though authors are cautious in their expectations.
electricity, collaboration is needed that they do exist in some markets – are not However, in future, in some locations and
aims to bring together relevant skillsets usually necessary, as solar costs have depending on the specifics of projects,
from a range of companies. already come down significantly. such as design complexity and floating
The adapted supply chain needed to Countries with subsidies for the structure, the LCOE of floating PV instal-
deliver floating solar will span develop- technology include Taiwan, which has lations could reduce to below that of
ers and EPCs experienced at developing, a specific feed-in tariff (FiT), and the US, ground-mounted PV, making them the
building and operating large-scale conven- where Massachusetts has a location-based cheapest form of solar generation.
tional solar plants, float manufacturers,
such as chemicals producers, companies
experienced in designing and developing Hybrid approach – hydropower and floating solar
floats for maritime applications, providers
The potential for building solar farms on hydropower water bodies could have unique advantages
of mooring and anchoring equipment and over other sites. Potentially capex costs could be streamlined as solar installations can piggyback on a
hydropower plant operators. hydropower plant’s under-used grid connection.
Hybrid clean generation plants are being commercialised in all flavours, such as solar+wind,
solar+wind+storage, around the world. In the case of floating solar PV and hydropower, especially in
Market support
dry regions, the two resources are highly complementary. Installing solar can reduce over-reliance on
Policy and regulatory framework needs to hydropower for electricity generation. “Hosting floating solar farms that feed into the same grid connection
be adapted in some markets, the report means that in summer months solar takes care of demand for electricity that hydropower generation would
adds. “As an example, in certain jurisdic- usually supply, preserving the water resource during dry seasons and spells,” says the World Bank’s Oliver
Knight.
tions like in the Netherlands, the owner-
Some hydropower resources have such large bodies of water that a solar array would only need to cover
ship of an asset, in this case a floating solar 1-2% to double their existing installed power capacity.
system, constructed above an immovable Some Asian countries are particularly interested in floating solar on hydropower reservoirs, including
site owned by another party, in this case, Vietnam, which has a lot of dams but limited available land. “Myanmar has initiated a floating solar study
and there is similar interest in India also,” says Knight.
a reservoir, can complicate how to enforce
In West Africa, where ESMAP is funding a number of studies on solar, floating PV plants on hydropower
certain lenders’ securities over the assets,” dams can bring different benefits as in many areas where grids are weak, hydro can firm up solar output,
says Paton. according to Knight.
On the other hand, floating solar Countries with floating solar on hydropower resources projects include Indonesia, with 200MW under
development, Vietnam with 47.5MW under development, Thailand with a 45MW and 24MW project under
projects can pose fewer development
development, Brazil and India with large-scale projects in development. Lithuania has a pilot project
headaches, especially during the early underway. According to SERIS there are likely to be others underway that they are not aware of.
permitting stages.
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