Floating PV for Saving Water
By Lotus Shaheen.
Climate change is rapidly influencing all areas of our lives. From aggregating forest wildfires in the United States to the verified recent decrease in the Arctic sea ice, the hazards imposed upon our ecosystem are grave and alarming. Floating solar power plants offer an innovative energy solution that not only caters our energy demands but also grants numerous environmental benefits, one of which is saving valuable water resources.
Evaporation of large water bodies such as oceans, natural and artificial lakes is inevitable. In fact, it is an essential part of our planet’s water cycle. That said, too much evaporation is a serious environmental danger. Over the past two decades, Earth has witnessed the driest and hottest summer seasons since the early twentieth century. A research paper by Yale School of Forestry and Environmental Studies suggests that evaporation of large water masses will increase by 16 percent by the end of the century, which can consequently alter regional climate trends and cause increased precipitation. A simple analogy to grasp the consequences of such abnormality is to imagine the Earth’s water cycle as a dysfunctional water pump that instead of transporting water from high to low pressure, it does exactly the opposite. In other words, rain is transported from drier to more humid regions.
Natural water masses, such as oceans, are less prone to over evaporation compared to artificial lakes. This is due to their typically turbulent air-sea interface, which may hinder the evaporation process. On the other hand, artificial lakes are directly at risk of drying out in the case of extreme weather conditions due to their increased water surface area and its stagnancy. A geo-referenced database by the Food and Agriculture Organisation illustrates the rise in accumulated water evaporation to about 350 km3 as of the year 2015. Although this analysis is intended as a rough estimation only built upon the available collected data, it reflects how water loss in dam lakes has increased drastically since 1950.
Floating PV Technologies
Floating PV technologies provide elimination measures against evaporation of artificial lakes. Acting as a shield, the offshore PV platforms can protect the water body against direct sunlight. Moreover, given their stable nature, dam lakes offer favorable installation conditions for the emerging technology. In an experimental study set in northern Chile, floating PV reduced water evaporation by 90% compared to an uncovered condition, all while yielding up to 68 Wp/m2 equivalent of electric power. The remarkable water savings have also been noted as a possible solution to save the US’s great lakes from drying out.
To sum up, floating PV demonstrates
 National Geographic, Environment. See how a warmer world primed California for large fires. Published November 15, 2018. URL: https://www.nationalgeographic.com/environment/2018/11/climate-change-california-wildfire/  IPCC. 2018. Special Report: Global Warming of 1.5°C, Chapter 00: Summary for Policy Makers