reheat double-flow steam turbine generator. The capacity of the turbine model is 240 MW; with the configuration it is installed in, Gateway's steam turbine has a nominal rating of 190 MW. The air-cooled condenser system, made by SPX Dry Cooling (now SPG Dry Cooling), is designed for a maximum ambient temperature of and back pressure of . It consists of six "streets" of six fans each, for a total of 36 fans; each fan is operated at 4160 volts by a 250-horsepower motor. A grid of 24 vertical screens installed beneath the fans shields them from wind. Emissions are abated by a selective catalytic reduction system using aqueous ammonia, which performs condensate hydrogen ion content (pH) control and reduction of NOx emissions. Additionally, there is an administration building and a control building, which contain the facility's control room, testing laboratories, and offices. These are both pre-engineered metal buildings, built by W. E. Lyons Construction. Upon its initial construction, the facility was described by the Brentwood Press as "big, imposing, noisy, metallic, tubular, gray, and sculpturally magnificent" but "not sexy". Operation The station, which is one of more than ten fossil-fuel power plants in Contra Costa County, currently provides power to half a million customers in northern and central California. In its first year of operation, the plant emitted 942,028 tons of CO2, 5 tons of SO2 and 83 tons of nitrogen oxide (NOx), while consuming 17,224,258,000 cubic feet of natural gas in order to generate 2,490,205 megawatt-hours of electricity. In 2010, the Trans Bay Cable was switched on, linking San Francisco's electrical grid with distribution infrastructure in the Contra Costa County. Gateway Generating Station was one of more than ten fossil fuel plants linked to San Francisco in this project. In June 2013, the Center for Biological Diversity submitted a legal notice of their joint intent (along with Communities for a Better Environment) to sue the Environmental Protection Agency for approving the project, claiming that its NOx emissions harmed local communities and "transform[ed] the chemical composition" of the nearby Antioch Dunes, causing hardship for tens of endangered Lange's metalmark butterflies. The lawsuit was intended to cause the EPA to reject PG&E's air emissions permit for the plant. In response, PG&E said that Gateway was "state-of-the-art", and that it had entered a voluntary Safe Harbor agreement for 12 acres of its property to be used as dune habitat for the butterflies