Mighty River Power has generated a record annual profit.
The State-owned electricity generator and retailer made $159.6 million in the year to June, a 43% increase on the previous year.
The company says the result was boosted by building a new geothermal generation plant and adding an extra 30,000 customers.
It benefited from the drought that led to low South Island hydro lakes during last year's winter, which boosted wholesale power prices.
The result was also boosted by a new geothermal plant and higher hydro generation.
Mighty River Power chief executive Doug Heffernan says the company also attracted an extra 30,000 customers to its retail arm, Mercury Energy, mainly in the lower South Island.
Mr Heffernan says Mighty River Power does not expect to repeat this year's result until 2011 when more generation comes online.
Mighty River will pay the Government a dividend of nearly $80 million, plus a special dividend of $150 million.