Energetica India nº91 July August 2020

CASE STUDY Harvesting solar energy in countries short on land space through use of floating photovoltaic systems, enabled by SABIC The photovoltaic equivalent of a tradi- tional power station is the solar farm. Made up of hundreds and even thou- sands of panels creating vast amounts of electricity for countless homes and businesses, solar farms inevitably re- quire a lot of space. But in many highly populated Asian countries such as India and Singapore, the land on which solar farms would normally be located can be scarce or expensive – sometimes both. One way out of this conundrum is to put the solar farms on water, through the use of panels supported on float - ing pontoons, all rigged together. These pontoons are hollow structures, made by blow molding plastics in a relatively low-cost process: imagine a whole net- work of waterbeds, but waterbeds made in strong, rigid plastics. Possibilities in- clude natural lakes, man-made reser- voirs, and disused mines and pits. According to the World Bank (Where Sun Meets Water, Floating Solar Market Report, 2018), the possibility of adding floating solar capacity to existing hy - dropower plants is of particular interest, especially in the case of largeof large hydropower sites that can be flexibly op - erated. It says the solar capacity can be used to boost the hydro-energy yield and may also help to manage periods of low water availability by allowing the hydro- power plant to operate in more cost-ef- fective modes. “Floating solar may there- fore be of particular interest where grids are weak, such as in Sub-Saharan Africa and parts of developing Asia,” it notes. Not only can floating solar farms occupy otherwise unused space, but they can also be more efficient than solar farms on land, because the water keeps the photovoltaic (PV) panels cool and so im- proves their ability to generate electricity. Second, the panels help reduce evap- oration from these expanses of water, which can be an important benefit when the water is being used for other purpos- es; as water becomes an increasingly precious resource, this benefit is only likely to increase. Furthermore, floating solar farms can improve water quality, by decreasing growth of algae. FPV farms are generally more cost-effi - cient to maintain due to the higher en- ergy production rate. Under the same weather condition, they could generate up to 12% more energy than land-based solar farms due to the cooling environ- ment and taking the reflection off of the water surface. Creating a cooler solar collaboration Floating solar farms are already a reality. In fact, the first system was built in Japan in 2007 for test purposes, and the first commercial installation, rated at 175kW, was installed on a reservoir in Califor- nia in 2008. Now, growth is picking up: the first plant larger than 10 MWp was installed in 2016, and bymid-2018, the total amount of energy around the world provided by floating PV (FPV) systems was 1.1 gigawatt-peak (GWp). According to the World Bank, there are more than 400,000 square kilometers of man-made reservoirs in the world, sug- gesting that floating solar has a theoret - ical potential on a terawatt scale, purely from the perspective of the available surface area. “The most conservative estimate of floating solar’s overall global potential based on available man-made water surfaces exceeds 400 GW, which is equal to the 2017 cumulative installed PV capacity globally,” it says. After ground-mounted farms and building integrated PV systems (BIPV), floating solar farms are already the third-largest method of solar energy generation. SABIC has developed grades of poly- Photovoltaic panels provide a clean means of harvesting energy from renewable source. It is ironic that in many countries where these panels work the best – around the tropics where the sun is highest –the technology is not as cost-effective as it could be. With its global expertise in production of a wide range of thermoplastics, backed up by applications development, technical support and services for customers, SABIC is helping change the equation. 50 energetica INDIA- July-Aug_2020