Floating Solar Q&A With Sika Gadzanku
April 7, 2023 by Kamyria Coney
Sika Gadzanku is an energy technology and policy researcher working on three main areas at NREL: conducting clean energy workforce analysis, providing short-term technical assistance to partners through the Clean Energy to Communities program, and understanding the opportunity space and impacts for floating solar (FPV) domestically and abroad.
Sika, could you dive a bit deeper into floating solar? What is floating solar, and how does it work?
Floating solar is a renewable energy technology, but I like to describe it as a renewable energy technology option that builds on existing technology types. So, it is essentially a solar panel floating on a body of water. The solar panels are on a flotation device that is anchored to the bottom of the body of water or to the shore. The system works like your typical ground-mount PV system. The only unique feature is that instead of being sited on land or on a rooftop, the system is on a body of water. There are two main ways floating solar is being installed: just the floating solar panels and floating solar paired with hydropower. This is very similar to typical solar energy systems on land and can be compared to solar plus storage.
Are there any challenges with having the solar panels on water? Does the water affect the technology (i.e., through corrosion)?
Yes, though it's actually the PV system itself that is potentially impacting the water. The research on this is limited, but we are hoping to understand how these installations could impact the ecology of the different environments in which they are hosted. Most floating solar systems have been installed on artificial bodies of water (e.g., tiny ponds, water treatment reservoirs, hydropower reservoirs), so you don't have as much of a concern with environmental impacts. However, there is growing interest in and development on natural water bodies, making it very important to understand the potential environmental impacts and whether this makes sense for a certain community or country.
Most of the systems are made of high-density polyethylene, a type of plastic, and they also use stainless steel in the structure. These materials are usually resistant to corrosion. There have been questions about recycling the plastic and looking at the circular economy of the materials. If deployment of floating solar continues to grow, we'll need to figure out ways to reduce, reuse, and avoid material waste.
Who would benefit from this type of technology?
There are various reports and analyses on this by a few organizations, like NREL, Wood Mackenzie, the Solar Energy Research Institute of Singapore, and the World Bank. The drivers are different depending on where you're looking, but there is a lot of interest globally, especially in regions where land is expensive or very scarce. So, think of island nations or countries and cities that have limited land, or places where the land is being used for agriculture, housing, and so on.
When looking at countries that have expensive land, we noticed that they also tend to have a lot of reservoir space and other open, artificial bodies of water. Countries have invested in floating solar through research and development and have developed pilot systems that drove a lot of the initial growth. Floating solar is still more expensive than ground-mount solar in some places, but it still made sense to invest in this specific technology.
Another benefit of FPV is the potential evaporation savings. Depending on the FPV structure, some panels are directly on the water, whereas others can be a few inches or feet above the water. This is still an active area of research, but the idea is that the panels above the water could function like a pool cover, which can save water. This is a huge potential benefit for arid and semiarid regions, but also benefits areas where it is not so dry. Evaporation happens on all bodies of water, so this reduction in evaporation due to FPV could potentially save water anywhere.
Is floating solar photovoltaics part of NREL's Renewable Energy Integration and Optimization (REopt) analysis platform?
No, not yet. FPV projects in the United States are quite small (1 to 4.5 MW), and though we've had conversations about incorporating FPV into the modeling capabilities in REopt®, it doesn't make sense at this time. We are seeing larger FPV projects (50 to 100 MW) abroad, where system planners will need to incorporate this technology type in their modeling efforts, but REopt mainly serves the United States.
What is the future of floating solar?
As someone introduced to this technology by my NREL colleagues, it has been exciting to see the growth of FPV. FPV is not necessarily the newest of technologies. However, early on in my research, there were still a lot of ideas and questions, with just a few projects here and there, whereas now, we are starting to see more FPV projects at larger scales globally. As a researcher, I am actively thinking about NREL's role in conducting research that could help answer many of the questions that remain about FPV. In the next 1 to 2 years, I think it is most important that we find answers to the questions about the ecological impact of solar panels on bodies of water:
- What are the trends in the ecological impacts of FPV?
- What are the water quality impacts of FPV?
- How is FPV affecting algae and wildlife, more broadly?
- How does maintenance of the FPV system disturb the ecosystem?
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