One of the advantages of floating PV is that the cooling effect of water keeps the modules operating at a lower temperature. But to take advantage of this, the module needs to be mounted close to the water at a low angle, making it more difficult to take advantage of the light reaching the rear of the module at the same time. And since locations above the water are often unshaded, mounting the module at a steeper angle, leaving both sides exposed to sunlight, poses further safety concerns.

But in terms of energy yield potential, there are advantages to combining the two — that’s the conclusion of a recent simulation experiment conducted by scientists at the University of Toronto. They simulated a series of floating bifacial PV systems in different configurations and found that north-south panels could receive 55% more solar irradiance than the same modules mounted on one side.

Under wavy surface conditions, this advantage is reduced to 49%; with east-west installations, the calculated irradiance increase is still 33%. Details of this simulation study are published in the journal Energy Conversion and Management in the article “A New Performance Evaluation Method for Bifacial Photovoltaic Solar Panels for Offshore Applications”. But the simulation study did not focus on the cooling effect of water, or the effect of temperature on component performance. Unusually, the researchers added an assumption that a cooling system was used between opposing panels. This is likely not achievable in a real installation, but the researchers can then assume a constant surface temperature of the panel and thus achieve maximum efficiency.

In addition to suggesting that temperature effects be studied, the authors of the paper suggest that future analyses of floating and double-sided panels should consider the difference between using a fixed tilt angle and installing trackers, as well as a cost analysis of different system designs.