Contact Energy will close the gas-fired Otahuhu power station at the end of next month.
The power generator and retailer said cheaper geothermal energy was the reason for shutting the 400 megawatt station.
The company said it canvassed potential users about taking power from the plant, but did not get enough support to keep it open.
Two weeks ago, Genesis Energy said it would shut down its last two coal-burning electricity generators at the Huntly power station in three years time.