The owners of 19 California coastal powerplants—including two nuclear facilities—may have to spend billions to install closed-loop cooling towers to protect marine life. The state Water Quality Control Board passed regulations on May 4 that require plants using once-through ocean-water intakes for cooling to reduce water use by more than 90%.
The rule, finalized by the board after five years of study and hours of debate, cites estimated annual mortality rates of 2.6 million fish and 19 billion fish larvae from up to 15 billion gal of water drawn daily to cool the plants. It “requires that the location, design, construction and capacity of cooling-water intake structures reflect the best technology available for minimizing adverse environmental impact,” says a board spokeswoman. She says detailed cost estimates won’t be known until plant owners submit them six months after the mandate passed internal legal review.