The state wants National Grid to reduce millions of fish deaths at its E.F. Barrett power plant in Island Park by upgrading the facility's cooling system.
The state Department of Environmental Conservation outlined the changes Wednesday in a draft version of a water pollution permit that the utility needs to operate the plant. It is the third time this year that the DEC has asked National Grid to modify cooling systems at its large, steam-generating power plants on Long Island.
The Island Park plant draws an estimated 294 million gallons of water each day from the western end of Barnum's Channel to cool the facility, then discharges the heated water to the eastern end. The DEC estimates billions of fish eggs and larvae get sucked into the plant each year; about 178,000 adult fish die when they are smashed against intake screens.
To comply with the federal Clean Water Act, the agency said National Grid should install a new cooling system that would send the heated water through cooling towers, then recirculate it through the plant.
The DEC said switching to so-called closed-cycle cooling would curtail water use by 95 percent. It would also limit disturbances to the marine ecosystem. The agency said the upgrades would reduce fish mortality by 98 percent for adult fish and 95 percent for eggs and larvae.
National Grid spokeswoman Elizabeth Margulies said Wednesday that the utility did not yet have an estimate for the cost of the changes. The utility "will file written comments addressing the feasibility, costs and the potential environmental benefits and adverse impacts associated with retrofitting the plant," she said.
The DEC's suggestions pleased environmentalists, who have lobbied for upgrades at National Grid's local plants with similar cooling systems: E.F. Barrett, Port Jefferson, Glenwood, East Rockaway and Northport.