Cooling power stations with brackish groundwater is one option for meeting cooling requirements while minimising freshwater usage. Power plants, especially thermal power plants, frequently require enormous amounts of water for cooling. Freshwater sources such as rivers, lakes, or reservoirs have traditionally been used for cooling, resulting in significant environmental implications and competition for finite freshwater resources.
Nontraditional water sources can be used to assist cope with climate-induced water hazards and meet rising water demand for decarbonization of fossil-fuel-fired power plants, but this could raise electricity generation costs by 8% to 10%.
A new study lead by a University of Wyoming professor finds that brackish or salty groundwater has the potential to replace fresh water in cooling coal and natural gas-fired power plants and increase energy infrastructure resilience, however there is a cost to doing so.
Water competition between the electric power sector and other industries is increasing as freshwater supplies are challenged by drought, climate change, and rapid socioeconomic growth. While transitioning to a low-carbon energy future, carbon capture and storage decarbonization of fossil fuel-fired power plants would dramatically increase water usage and worsen water competition. Water scarcity forces power plant operators to investigate alternative water sources.
Nontraditional water sources can be deployed to help cope with climate-induced water risks and tackle the increasing water demand for decarbonization of fossil fuel-fired power plants. Treatment of brackish groundwater for thermoelectric generation cooling can help alleviate potential competition for freshwater resources among various sectors in water-stressed regions.
Haibo Zhai
“Nontraditional water sources can be deployed to help cope with climate-induced water risks and tackle the increasing water demand for decarbonization of fossil fuel-fired power plants,” wrote the research team, led by Haibo Zhai, UW’s Roy, and Caryl Cline Distinguished Chair in the College of Engineering and Physical Sciences. “Treatment of brackish groundwater for thermoelectric generation cooling can help alleviate potential competition for freshwater resources among various sectors in water-stressed regions.”
The research appears in the journal Nature Water, with Zhai’s UW Ph.D. student, Zitao Wu, as the lead author of the paper. Other contributors are from the National Energy Technology Laboratory in Pittsburgh, Pa. This journal publishes the best research on the evolving relationship between water and society. It’s the second paper of a multiyear project funded by the U.S. Department of Energy; the first paper, published last year in the journal Applied Energy, examined the possibility of switching from water cooling towers to dry cooling systems at fossil fuel-fired plants.
Removing excess dissolved salts and minerals from brackish water can itself be energy intensive and produce concentrated brines requiring disposal. A method called zero liquid discharge minimizes environmental impacts of desalination but is particularly costly.
The scientists investigated the technical and economic feasibility of various desalination techniques. They also calculated how much fresh water would be saved by treating brackish water for power plant cooling, and they assessed the cost-effectiveness of brackish water treatment retrofits – as well as the influence on power plants’ net producing capacity. They concluded that upgrading power facilities to treat brackish groundwater may practically eliminate the need of fresh water while raising electricity generation costs by 8% to 10%.
“Our study reveals trade-offs in freshwater savings, cost, and generating capacity shortfalls from desalination deployment,” Wu explains.
The researchers advocate for the further development of technology to treat brackish water, as well as the investigation of additional atypical water sources for power plant cooling. These include treated municipal wastewater, oil and gas extraction water, and carbon dioxide storage reservoirs.
According to the researchers, the trade-offs discovered for diverse alternative water sources will fill knowledge gaps to better inform water-for-energy decisions and management.
