Coastal power plants that rely on seawater to cool their systems must cut their water intake by 93 percent over the next several years to comply with new state rules issued by the state Water Resources Control Board. The 19 affected power plants, which have the combined capacity to draw more than 15 billion gallons of water daily, must submit compliance plans to the water board by April 1. 


The Dynegy power plant at Moss Landing, which is permitted to intake 1.2 billion gallons daily, needs to comply by the end of 2017. 


Dynegy officials will not release plan details. “We’re developing the plan as we speak, and we’ll be looking at a number of different technologies,” says Dan Thompson, vice president of operations. 


The plant now uses a once-through cooling system, which returns water to the ocean at a high temperature. Small sea life floats into intake pipes and is essentially cooked in the cooling process. The new rules aim to reduce mortality in accordance with the Clean Water Act of 1972. 


Joe Geever, California policy coordinator for Surfrider Foundation, one of the organizations that has championed the issue in court, says the water board rules hasten the direction market forces would have taken. David Byford, a spokesperson for Dynegy, disagrees, describing two existing Moss Landing generators as “modern, highly efficient, natural gas, combined-cycle units.” 


To stay ahead of potentially similar rules for desalination plants, the regional water project proposes sub-surface pipes that pull water from below the sea floor. A private desal venture led by Moss Landing entrepreneur Brent Constantz of Calera recently indicated it would pull deep water where there is less sea life. Geever, who favors conservation over desal, counters, “There are fewer organisms, but that makes each one of them more valuable.”