Rapid City is located on the boundary of the Western and Eastern power grids. It is served by the hydroelectric plants of the two Mainstem dams on the Missouri River, and the large coal fields and power plants of the Powder River Basin of Wyoming. It is located where the two national power grids connect with each other, allowing switching of electrical power from east to west and vice versa. Rapid City had its own coal-fired power plant but could not afford to meet current air pollution standards and closed it. Closed for similar reasons were coal-fired power stations near Gillette, Wyoming. The Ben French power station located within city boundaries shut down September 2012, more than two years ahead of its scheduled shutdown. Rapid City now obtains much of its power from the Missouri dams and importing it from elsewhere. Following the shut down of the plants dependent on cheap, polluting coal, electrical rates have risen. The city has had to spend more to import electricity over a longer distance.