Floating solar, also called floatovoltaics, is a concept that’s catching on, especially in areas where land is in short supply. The panels are “floated” on a body of water, whether a small irrigation pond or massive reservoir. Compared to installing solar structures on land, there are fewer regulations for structures on bodies of water that are not used for recreation, installations are faster and there are numerous other advantages.
The global floating solar panel market is expected to grow at a CAGR of 65.1% through 2023, according to a recent report from Research and Markets, reaching $842.0 million. The tracking floating solar panels market size is predicted to exceed $250 million by 2024, according to Global Markets Insights. Factors accelerating the overall growth of floating solar include subsidies and tax benefits offered by governments around the world, scarcity and cost of open land and the increased interest in moving to renewable energy sources.
Worldwide Floating PV Installations. Source: Adapted from Solar Asset Management—North America and NREL. Courtesy of Upsolar.
Where solar floats
In Japan, the floating solar market is expected to exceed 400MW by 2024. Limited land resources are the major growth factor for the Japanese market, coupled with the 2016 installation of a 13,7MW floating solar plant by Kyocera.
In areas where drought has been a problem, such as in California, floating solar is seen as a solution to several problems. Especially in wine country, where irrigation ponds are plentiful, the wineries themselves can be powered by renewable energy. The Kunde Family Winery in Sonoma County, California for example, has seven lakes on its land. Ciel et Terre installed a 10kWp PV system, which Jeff Kunde, Chairman of the Board at Kunde, said will help clean the water as well as provide power for the winery.
Installations around the world
Floating solar has widespread use on bodies of water not used for recreation. These include wastewater, sewage treatment and irrigation ponds, reservoirs and bodies of water at hydroelectric plants. One of the greatest uses of floating solar is to install it right where the energy is needed, such as at waste water treatment plants, wineries or hydroelectric plants.
In the UK, a floating solar plant with 12,000 panels covers 45,500 square meters in Hyde on the town’s Godley Reservoir. The plant is expected to generate 2.7 GWh per year. In Brazil, a floating solar plant covers 50,000 square meters at the Balbina hydroelectric plant in the Amazon. The Kyocera plant (mentioned above) is comprised of about 51,000 Kyocera solar panels and is installed on the Yamakura Dam reservoir. In Singapore, Upsolar Pte. Ltd. deployed a floating solar system at Tengeh Reservoir. The system is part of a project overseen by Solar Energy Research Institute of Singapore (SERIS) as part of Singapore’s green initiative to assess the viability of using floating solar systems. In the US, Ciel et Terre installed a 31.5kWp floating solar array in the storm water storage reservoir located at Orlando Utility Commission’s Gardenia facility.
Key industry players in this market include Ciel et Terre, Kyocera, Novaton AG, Pristine Sun, SPI Energy, Solaris Synergy, Upsolar, Vikram Solar, among others. Michael Cheung, Marketing and Communications Director of Upsolar said that floating solar is a part of Upsolar’s marketing strategy, “In fact we’ve been working on developing floating solar for a few years. The project in Singapore is what really gave us the signal and confidence that our technology and solution is ready to expand on a larger scale.”
Compared to land-based
Other than fewer regulations on water-based solar installations, the main difference between land- and water-based is the foundation for the solar panels. Floating solar installations are often on lightweight tubing that float on pontoons anchored to the bottom or attached to the shore. Unlike land-based, floating solar doesn’t require drilling and securing a rigid foundation, therefore, Installation of solar on a body of water is significantly faster than on land. According to Upsolar's Cheung, the Singapore installation took just 5 days.
One would think that floating a small electrical power producing plant on top of water would create safety challenges. However, because the solar and wiring floats above the water, the installation--from a wiring and grounding standpoint--is not much different than land based. The inverters, for example, are the same than for ground-mounted system. Upsolar described its grounding or earthing as having a bounding path between the modules and the mounting structure through the mounting clamps. The structure is then connected to the ground either on the bottom of the reservoir or on the bank, whichever is closer/easier to implement.
Ciel et Terre developed Hydrelio technology for floating solar on water. It consists of modular lego-type floaters assembled into rows using connection pins – each one of these main floaters supports a PV module. The rows are held together by aisles of secondary floaters, which ensure the overall structure’s buoyancy, spacing between the PV panels, and double as maintenance alleys. PV panels are installed and the structure is simply pushed out or towed into the water. As the solar island is being assembled, anchors are installed on the perimeter banks and at the bottom of the body of water the system is placed in. The installations use a typical grounding slot on the module frame, and they run a cable between each panel that goes back to the shore in the same waterproof drain conduits that contain the DC cables.
The advantages of floating solar are many. In areas with a dry climate, floating solar can help save water by limiting water evaporation. Floating solar panels also offer increased efficiency because the cooling effect of water maintains a steady temperature. And the reduced sunlight on the water’s surface has been found to reduce algae growth, which is beneficial because algae build-up in an annoyance at best and a maintenance headache at worst. Curtailing its growth is accomplished by using herbicides and algaecides, so not only are money and time save, but the use of potential toxins is reduced.
The one drawback or challenge to floating solar is basically that it can’t be used on all bodies of water. The solar panels used in floating installations have a special coating to make them more impervious to corrosion or rust. However, the coatings do not safeguard panels against corrosion from saltwater and therefore, floating solar won’t be taking to the seas anytime soon.
The direction of the floating solar market is one that industry experts will be watching closely. At Intersolar Europe, which takes place 31 May to 2 June, a session will take place on 31 May entitled Floating Power Plants: Concepts, Technologies, Case Studies.
Written by Anne Fischer, Managing Editor, Solar Novus Today