R E N E W A B L E E N E R G Y

Water Evaporation Rates: The Benefits of Floating Solar

AUTHOR: Hannah Brendell PolicySpecialist-Intern@RDJConsulting

Water and the future of water spurred UN Water to bring together global leaders, ministers, and changemakers to discuss SD 6 indicators and the progress made In consideration of World Water Day 2023, RDJ Publishing through the RDJ Briefing, features “Floating Solar”.

UN Water states that “Access to water and sanitation is a human right A well-managed water cycle underpins progress across the 2030 Agenda for Sustainable Development, particularly in relation to hunger, gender equity, health, education, livelihoods, sustainability, and ecosystems”

Evaporation requires a lot of energy, and that energy is provided by solar radiation (basically the Sun). the level of ambient humidity is also a factor in evaporation rates

Thus, it is not surprising that evaporation rates are higher in areas of the globe that generally experience higher ambient temperatures

Renewable energy can be used to provide energy that can activate cooling systems, but this then requires a surface area to place say solar panels to produce that energy. Hence, Floating Solar, also known as floating photovoltaic (FPV) or floatovoltaics is a method of setting a solar array on top of bodies of water such as lakes, reservoirs, dams, or ponds to generate electricity

There are various reasons and benefits for having floating solar systems but some of the main ones include Water conservation where the water surface covered means less water is lost to evaporation which is especially useful to water-stressed countries. Land resource conservation through which solar arrays are placed on top of bodies of water means more land is available which is especially important in densely populated regions. Convenient operations and maintenance due to water sources often being located close to where people reside there are fewer barriers such as distance from point of generation to point of need to overcome This ultimately means maintenance and operations of the floating solar array will be easier to manage. Power generation improvement: due to water being a good cooling medium, the temperature of floating solar panels is kept lower than roof-mounted solar PV plants which allow for higher electricity generation as efficiency losses are lowered

Despite the benefits of FPV there are obstacles that need to be considered The lifespan of floating solar is between 25 to 30 years but due to its proximity to water it faces unique challenges such as equipment corrosion which means it often requires more maintenance than other solar systems. Additionally, require 10-15% higher capital investments than land solar projects

The conventional intermittency issues due to both movement of the sun and cloud cover that plague solar would still exist for floating solar but there is the potential to use it as a backup particularly with hydropower and general water reservoirs. Not only would they allow for the added benefit of lowered evaporation, allowing for more stable electricity production but they could also feed into the existing grid networks and support pumping operations

The growth of floating solar is currently depicted in the various projects gaining traction across Africa In 2022, Tunisia started operating its first floating solar plant The floating solar plant would add an extra 265MWh annually of clean energy to the national grid operated by Tunisian Electricity and Gas Company (STEG) In South Africa smaller floating solar projects, particularly on farms, are happening more frequently and in some cases are even replacingconventionallandbasedsolarprojects

When it comes to potential floating solar projects there are developments underway to look at floating solar withstanding rough waters like on the open ocean Countries such as Norway already have operational openoceanfloatingsolararraysintheSingaporeStrait Should these developments take off they have the potential to make electricity access to large percentage of the global populationlivingclosetotheoceansmucheasier

WheredoyouseepotentialforfloatingsolarinAfrica?Share your thoughts with us at briefing@rdjpublishing.africa as theconversationcontinues.

Readings:

https://www unwater org/about-un-water https://www sciencedirect com/topics/earth-and-planetarysciences/water-evaporation https://joint-research-centre ec europa eu/jrc-news/floatingsolar-panels-african-hydropower-reservoirs-2021-02-26 en https://joint-research-centre ec europa eu/jrc-news/floatingsolar-panels-african-hydropower-reservoirs-2021-02-26 en https://www iberdrola com/innovation/floating-photovoltaic