Mighty River Power Limited engages in the generation, trading, and retailing of energy in New Zealand. It owns and manages a portfolio of generation assets in the North Island that include the Waikato hydro scheme, geothermal interests at Mokai and Rotokawa, the southdown co-generation station, and a biomass generation program. The company offers electricity and gas services to residential and small business customers in the central and upper North Island, and large business customers in New Zealand under Mercury Energy brand. Mighty River Power also provides meters and meter-reading services to residential and commercial customers in Auckland, and to other electricity retailers. As of December 31, 2006, it served 344,000 electricity customers and 27,000 gas customers. The company is based in Auckland, New Zealand.