Mercury NZ (formerly Mighty River Power) generates more than 15% of New Zealand's electricity and is one of the four major electricity generators and suppliers in the country. All electricity is now generated from renewable sources, which makes it one of the lowest-cost providers of electricity. The company operates nine hydro stations and five geothermal power plants, all located in the North Island. Mercury sells electricity to residential and commercial customers and has the largest share of the key Auckland market.