BLOOMINGTON, Ind. – Hydropower plants, which use water to generate electricity, are seen as a low-carbon renewable energy source, but some of these facilities can generate greenhouse gases within the range of fossil-fueled power plants due to methane emissions stemming from the decomposition of biomass and algae growth in stagnant water.
To combat the issue, which impacts as much as 10 percent of the world’s hydropower facilities, a new study suggests using floating photovoltaic (FPV) panels to offset the greenhouse gas footprint of hydropower plants. The study, led by Rafael M. Almeida, an assistant professor at the Paul H. O’Neill School of Public and Environmental Affairs, is featured in an article recently published in the journal Nature Sustainability.
“This paper stems from my work combining these two renewable energy systems—hydropower and FPV,” said Almeida, who recently joined the faculty at the O’Neill School. “Hydropower, while generally considered low-carbon, can emit substantial amounts of GHGs. Surprisingly, some hydropower facilities end up being more GHG-intensive than fossil fuel-based energy. Moving forward, there is a need to avoid building new GHG-intensive hydropower projects and to devise strategies for decreasing the GHG footprint of existing ones.”
Floating solar photovoltaics are solar panels that are mounted on floating structures. Those structures are then moored to the bottom or the shore of a body of water. In some uses, floating solar photovoltaics can collect energy from the sun based on reflections of the sun off the water.
To see if it would significantly reduce the overall GHG intensity of hydropower facilities, Almeida and his colleagues explored the potential of integrating FPV into GHG-intensive hydropower reservoirs on a global scale, combining a GHG-friendly energy source with a GHG-intensive one without the need for extra land.
“Our findings highlight the promising global potential of using FPV to offset hydropower-related emissions,” Almeida said. “Quantifying the GHG offsetting potential of FPV can advance broader climate objectives and offers a practical solution for climate-smart hydropower management. For example, achieving low-GHG benchmarks can enable hydropower facilities to earn sustainable hydropower certifications. This is especially important because directly addressing hydropower emissions at the source has historically been challenging.”
Despite the encouraging findings, more research is needed.
“Although FPV shows promising GHG offsetting prospects, the broader social and ecological implications of using FPV on water bodies are not yet fully understood,” Almeida said. “Exploring both positive and negative impacts have been the focus of my current and future research.”