Mighty River Power says its geothermal expansion plans are on track.
The electricity generator and retailer, which the Government plans to partially list later in the year, says its $466 million Ngatamariki geothermal plant has experienced some difficulties drilling wells.
But Mighty River expects the plant to be commissioned by the middle of next year, as planned and within budget.
Meanwhile, its international geothermal plans continue. Mighty River Power says the 50 megawatt $400 million John L Featherstone plant in California, in which is has a majority stake, is now up and running, and supplying power to an Arizona utility.
A second geothermal plant next door is also being planned, with construction expected to start late 2013.
Mighty River Power has previously committed up to $250 million to geothermal power projects overseas in the US, Chile and Germany.