IEC
The potential for floating solar photovoltaic panels and
farms is tremendous, despite initial deployment costs. The IEC is preparing the
standards for it to be used safely and efficiently – and in all weather
conditions.
article here
Floating solar photovoltaic (FPV) panels – sometimes called
floatovoltaics – is a relatively new renewable energy option, but one with huge
potential. According to the IEA, in 2023, solar PV alone accounted for
three-quarters of renewable capacity additions worldwide. Yet most of the solar
panels installed so far lie on land, which pose crucial issues for land use
particularly in countries where land is at a premium. This includes island
states, for instance, but also countries with high population density
where land is a constraint.
It’s one of the reasons why the deployment of solar
technologies which float on water are predicted to increase rapidly over the
next few years. “With 70% of the world covered with water, research and
development of FPV on ocean platforms opens a new era of solar energy with the
advancement of robust floating structures,” an international research team
states in a review of the field published in April.
The scientists conclude that FPV systems outperform
land-based solar PV systems under similar conditions but warn that offshore
weather and harsh ocean currents may pose serious challenges to FPV structures.
“Therefore, research and development efforts addressing this issue are
crucial,” they say.
Shading the water
FPV modules are solar PV panels mounted on raft-like
structures that float on a body of water such as drinking water reservoirs,
quarry lakes, irrigation canals, hydropower or agriculture reservoirs,
industrial ponds and near-coastal areas.
While one of the obvious advantages of floating solar PV
tech is that it avoids taking up land space. It can also allow for power
generation to be sited much closer to areas where demand for electricity is
high. This makes the technology an attractive option for countries with high
population density and competing uses for available land.
Floating sun-powered farms also solve another problem
plaguing conventional land-based solar PV modules: inefficiency when the panels
become too hot. FPV panels generate extra energy because of the cooling effect
of the water they hover over. The proximity to water of floating solar modules
is estimated to increase their electricity production by up to 15%.
Stationary floating panels also double as shades for the
water body, which reduces the evaporation of water. This is an added advantage
in areas where water is becoming scarcer. (For more information on the
preservation of water read: when cities run dry: tackling water scarcity).
Asia leads the way
The technology is particularly well suited to countries in
Asia where land is scarce but there are many hydroelectric dams connected to
the electricity grid. The world’s first floating solar plant was built in
Japan. The country’s inland lakes and reservoirs are now home to 73 of the
world's 100 largest floating solar plants. A floating solar plant in East China
generates almost 78 000 megawatts (MW), enough to power 21 000 homes. A
South Korean plant delivers 102,5 MW, capable of powering 35 000 homes.
Island state Singapore has constructed a solar farm with 13 000 FPV
panels in the Strait of Johor with the ability to produce up to 5 MW –
sufficient energy to power 1 400 residential flats all year-round. A project
at Sirindhorn Dam in Thailand is estimated to help reduce carbon
emissions by 0,546 tons per 1 000 kilowatt per hour (kWh) produced.
Covering just 10% of all man-made reservoirs in the world
with FPV panels would result in an installed capacity of 20 Terawatts (TW) – 20
times more than the entire global solar PV capacity today, according to an
analysis by the Solar Energy Research Institute of Singapore (Seris).
Reliability and financial concerns
As it stands however, less than 1% of the world's solar
installations are floating, according to the Centre for Renewable Energy
Systems Technology at the UK’s Loughborough University. This is partly due to
technical and financial constraints. Saltwater causes corrosion while
positioning panels at the right angle is tricky and expensive on a floating
platform.
Although panels clip together and are then pushed out onto
the water, they require an anchoring system, which helps to keep the pontoon
stable. The deeper the body of water, the higher the cost of the anchor. Also
influencing deployment costs are water level variations, characteristics of
soil/bedrock and the type of floats used to support the PV modules.
For example, the reported anchoring costs for the Anhui
project in China are relatively low at around 10 USD/kW. It is in shallow
water and has benefited from the local manufacturing facilities and labour
force. But for a similar scheme in Japan the anchoring price is substantially
higher.
Researchers also point to the lack of supporting
policies and development roadmaps by governments that could hinder the
technology’s growth and viability. Installations of floating modules on
freshwater bodies may also face opposition if they compete with other leisure
activities, such as angling. There are further concerns that large-scale plants
may harm marine ecosystems by blocking sunlight. The risk of disruption or even
destruction due to volatile weather is also discouraging investment. A typhoon damaged
Japan’s largest FPV plant in 2019, for instance.
Where standards can help
As is the case with other emerging technologies, standards
can help to bring the cost of FPV down. They can also set benchmarks for the
construction of solar PV plants, ensuring they are able to withstand severe
weather conditions and do not pose problems for the environment. The IEC is
working on a new technical specification (TS) due to be published at the end of
2024, which establishes the guidelines and recommendations for the design of
FPV plants. The plan is to later expand the TS into a full standard. Issues
addressed include how to implement electrical earthing in an installation over
water and carry out insulation resistance measurements, how to implement proper
mooring and anchoring of the modules, selecting the suitable cables and
connectors, as well as cable routing and management, location of inverters and
transformers (e.g. over water or on land) – right down to issues such as the
cleaning of bird droppings!
Standards are required because of the technology challenges
that need to be addressed but also because basic estimates of the potential for
floating solar are overwhelming. One study found that solar panels floating on
just 1% of Africa's hydropower reservoirs could double the continent's
hydropower capacity and increase electricity generation from dams by 58%.
This is precisely because FPV panels stop water from evaporating. According
to nature.com, if 10% of the world’s hydropower reservoirs were covered
with FPV it could generate as much electricity as all the world’s operating
fossil fuel power plants combined. The market is expected to grow 43% a
year over the next ten years, reaching USD 24,5 bn (Euro 22,2 bn) by
2031. Standards will enable the tech to truly prosper alongside other renewable
energies as we aim to meet our net zero targets.
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