Pacific Gas & Electric will replace two aging fossil-fuel plants at its Humboldt Bay facility with 10 units using reciprocating engine technology. The deal is worth more than $120 million (100 million euros). Announced April 10, it calls for 163 MW on-site. The repower will run on natural gas. It will not use water for cooling. PG&E applied to the California Public Utilities Commission April 11 for a requisite certificate of public convenience and necessity. The Humboldt Bay site, just south of Eureka, hosts two 50-year-old fossil-fuel units and a shut-down nuclear plant. PG&E contracted for W\u00e4rtsil\u00e4 North America to provide the engines in a turnkey arrangement. The basic technology is similar to large vehicle engines - using pistons to drive it instead of steam to turn turbines, according to Mikael Bachman, W\u00e4rtsil\u00e4 business development director. The engines are air cooled - much like a car radiator. The site's current power plants use seawater for cooling. Bachman said the air pollution from the plants would not exceed the latest standards. The company, he said, will use scrubbers to reduce NOx and catalysts to reduce carbon monoxide. PG&E maintains that the power plant will produce 90 percent fewer ozone precursors and be 35 percent more efficient than the existing plant. The new power facility will have its own section on the Humboldt site, away from the nuclear plant that shares the landscape with the two fossil-fuel units, according to Bachman. He did not think there would be any problem with the building and operations while the nuclear plant continues to be decommissioned. W\u00e4rtsil\u00e4 has similar power plants in Nevada and Colorado. However, the California installation will be the company's largest in North America.