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Moving off land

Solar power developments are taking PV into the water

Floating solar system
Floating solar systems have a greater potential for PV power than just keeping the technology on land, according to some companies

PV plants have for a long time been built onshore, with installations taking up acres of land in the countryside, the desert and, more recently, the cityscape. But now developments are happening to bring the solar farm concept onto lakes, reservoirs and the sea.

Companies across the EU, such as French firm Ciel et Terre and Norwegian risk management services group DNV, are working on developing innovative floating solar systems, which they say have a greater potential for PV power than just keeping the
technology on land.

So why install floating solar systems? “Simply because, in many countries, there is a lack of land to install large scale groundmount solar systems,” says Bernard Provoust, CEO of Ciel et Terre. “It is important that solar power brings solar power of 10MW or more.”

Provoust says that floating “increases power production and improves return on investment”. This is because panels and marine cables installed on water stay cooler, generate more electricity and have a higher ROI than rooftop or ground mount systems of the same size. He says floating solar systems therefore represent a serious alternative to ground mounted solar systems. He also says large inland water bodies around the world are usually located to a point for power distribution.

“With quarries, lakes, dams, irrigation reservoirs, water-treatment sites or floodable lands, the possibilities are infinite. And most of the time, close to a connection point.” The state of Karnataka, in India, for instance, has 36 000 irrigation lakes of more than 24 acres. Ciel et Terre has developed its patent floating technology, Hydrelio. Designed to resist tough environmental conditions, and to produce cost-effective solar electricity, Ciel et Terre says the Hydrelio solution allows the “realisation of large-scale floating solar systems”, thereby contributing to a “better energy balance.”

The innovative floating solar platform allows standard PV panels to be installed on large bodies of water, such as drinking water reservoirs, quarry lakes, irrigation canals or remediation and tailing ponds.

Easy to install and maintain, the system is adapted to all types of lakes, natural or industrial. It consists of standard PV panels, which are mounted on floats. These floats are manufactured in HDPE (high-density polyethylene) or PP (polypropylene) in a process called blow moulding extrusion.

The primary float, slightly narrower than the PV panel, is designed to support the panel. A rail is also created during the manufacturing process, on which the workers can insert santoprene extruded rods designed to fix the PV panel by its frame. A secondary float is designed to link the primary floats together. This maintains the distance between the PV panel rows and also can be used for maintenance operations.

The French company says the floating solar system is more energy efficient than onshore PV, while making good use of water resources. “Thanks to the cooling effect that water has on PV panels, our systems produce more energy than land-based systems of a similar size,” says Ciel et Terre. “By shielding the water from the sun’s heat, our platforms also reduce water evaporation, increasing your return on investment.

“A simple and affordable alternative to ground-mounted solar systems, our floating solar platform Hydrelio is particularly well suited for energy and water-intensive industries who cannot afford to waste either land or water. Wineries, dairy farms, fish farms, mining companies, wastewater treatment plants, irrigation districts and water agencies are all examples of organisations which benefit from the synergy that our system creates between sun and water.”

Ciel et Terre is now working on developing a 12MW and a 4MW floating solar system that will power thousands of homes in the south of France, without taking up any land. Three other floating solar projects representing a total of 31MW are also under permit review in the country.