Floating solar panels, sometimes nicknamed “floatovoltaics,” are poised for growth around the world, following Japan’s lead. In late May, Japanese firm Kyocera unveiled the world’s largest array of floating solar panels, on the surface of a reservoir in Hyogo Prefecture. The 9,072 waterproof solar panels have a 2.3MW capacity, and the firm is planning many more projects around the country. The largest, which is expected to be completed in March 2016 on the Yamakura Dam reservoir, will use some 50,000 panels with a collective 13.4MW capacity.
For countries where land is scarce and expensive, as in Japan and Singapore, floating solar panels are a viable alternative. These panels are also significantly more efficient than land-based ones, because the water cools off their excess heat. A study by the Korea Water Resources Corporation found those efficiency gains to be 11% or more, while Felicia Whiting of Australia’s Infratech Industries reported a 57% gain. Floating solar panels also lessen the evaporation of the underlying water, which is extremely useful in dry areas. Whiting said they prevent water evaporation up to 90% of the surface area covered, and that a 1MW plant would save about 70,000 kiloliters of water per year. By capturing the sunlight, Infratech’s 4MW of floating panels on a wastewater treatment pool in Jamestown, South Australia also prevent the outbreak of blue-green algae, a major concern for water quality.
In the U.S., Pristine Sun announced in February that it will build 12.5MW of floating solar panels in California’s Sonoma County, on six irrigation water storage ponds. Without using valuable agricultural land, this will reduce evaporation and dependency on fossil fuels, and create local jobs — a win for everyone. (The world’s first such project was pioneered at a winery in Napa Valley, California in 2007 with 1,000 solar panels on an irrigation pond.) Separately, Solar Power Inc. (backed by China’s LDK Solar Co.) formed a joint venture in March with Aqua Clean Energy to develop floating solar projects in the southwest U.S. and Mexico; they have already identified more than 50 megawatts of potential projects.
Other countries have announced large-scale projects in the same vein. Last June, India awarded a contract to set up a 50MW floating solar panel project in Kerala. Brazil, which gets 80% of its electricity from hydropower, is suffering from a severe drought — so it announced in March that a 350MW pilot project of floating solar panels will be initiated at the Balbina hydroelectric plant in the Amazon. (For reference, even if the water level was not abnormally low, Balbina’s maximum capacity is only 250MW). And last December, South Korea’s prototype 465kW floating Sunflower Solar Power Plant was announced to be 22% more efficient than land-based panels. (It uses a tracking system to rotate the panels so that they receive the most direct sunlight throughout the day.) The Korea Rural Community Corporation now plans to use 5% of the country’s water surface for the installation of floating solar panels, totaling 4GW.
However, three main obstacles remain against widespread adoption of this technology: maintenance, aesthetics, and environmental impact. Maintaining floating solar panels means going out in a boat and doing repairs, which is not as easy or accessible as on land. There are also potential issues of corrosion and other water-related damages. But “one reason we chose Ciel et Terre’s floating platforms,” said Ichiro Ikeda, general manager of Kyocera’s solar energy marketing division, was that they “are 100% recyclable and made of high-density polyethylene that can withstand ultraviolet rays and corrosion.” Furthermore, in tests their system resisted winds of up to 118 miles per hour. And they are safe from earthquake damage, because they have no foundation—just an “adequate anchoring system that ensures its stability,” according to Ciel et Terre.
Still, people may not be thrilled about covering up bodies of water, even partially, with solar panels. “The appearance of water is still far more beautiful than that of a photovoltaic cell…” said Singapore’s Environment and Water Resources Minister Vivian Balakrishnan. But he added that his country will install floating solar panels “where we can, and where it makes economics and operational sense…” That said, there are plenty of artificially-created bodies of water that would be prime locations for floating solar panels, such as irrigation canals, quarry lakes, tailing ponds, and wastewater treatment pools.
Where environmental health is at stake, such as in reservoirs and lakes, impact studies should be made, and they should be kept to high standards. One compromise would be to install some floating solar panels in the middle of bodies of water, far from the shores that are richest in biodiversity. But the environmental impact must be miniscule, and local communities must be in favor of the efforts, otherwise there would be a rare turn of conservationists against renewable energy. So it is likely that floating solar panels will always be a niche market compared to general solar power.
Currently, floating solar panels are limited to freshwater. The waves and corrosive salt of the oceans present tougher challenges, and in general it makes more sense to generate electricity closer to where it will be used. Undaunted, French firm GEPS Techno is developing the 30m-diamter MLiner (and a mini version), which is a floating ocean platform that produces energy from solar, wind, wave, and tidal sources. The MLiner could be used to bring electricity to isolated places like small islands or oil and gas rigs; GEPS Techno hopes to launch it by the end of 2018.
Whether in freshwater or saltwater, expect more floating solar panels to spring up around the world.