Floating PV – potential and challenges

Posted by Karolis Mirinavičius

Floating PV solution has been around for a decade already (the first commercial FPV system was installed in 2008 in Napa Valley, California, USA), but in recent years it got its pace and now many projects are being developed in various locations. More than 70 countries are already looking or already have installed floating PV systems, main regions are Asia, Europe, South and North America. It is estimated that installed capacity will double in the following two years (when comparing to 2019 numbers).

The main drivers for such solution development are the ability to utilize free space on the water surface especially locations where there is available electricity infrastructure (like hydro dams or pumped hydro storage reservoirs) and increasing challenges to utilize available land.

Additional benefits come in with installed FPV systems, like increased energy yield, with the water-cooling effect (it was proven by testing that efficiency can increase by up to 10%, theoretically even more). In theory there was a potential to have better efficiency with bi-facial modules, but test proved that water is not the best surface for reflecting the sun directly into the modules and the results of increased yield was minimal. While glass-glass modules were proved to be more durable in such installations with more harsh conditions. For specific locations water evaporation problem can be solved by covering the surface with FPV.

While many potential benefits sounds promising there are many challenges to be addressed. FPV projects comes with new components like pontoons and anchoring systems. There are quite a few companies that provide these systems, and many has experience working with offshore oil industry, where sophisticated underwater engineering solutions are being used as well. Nevertheless, floating structure for PV and anchoring requires new ideas and engineering perspective, the design becomes very sensitive in regard to the environment, where the impact of wind, potential waves, freezing temperatures above the ground must be evaluated. Rapidly changing water levels, specifically when installing FPV next to operating hydropower dams, or on hydro pumped storage reservoirs. The bed of water body becomes very important as well, since the anchoring system must provide reliable safety within various conditions.

The other aspect is regulation and permitting for such constructions and systems to appear on water surface. There are many different views when talking about renewable energy like FPV development in separate countries. While some already has set up goals and even specific feed in tariffs for FPV systems (f.e. Vietnam), others are still heavily regulated with the ability only to test FPV in very specific locations.

When talking about specific locations, hydropower dams and hydro pumped storage powerplants proved to have huge potential for installation of FPV systems. Available water bodies can be utilized for such project and the electrical infrastructure most of the time is already there. Some of the projects has shown that hydro + PV systems balance each other and provide more produced renewable energy. Ignitis group is developing floating PV pilot project on top of upper reservoir of Kruonis PSHP plant, you can check more about this project here.

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