Mighty River Power's electricity sales and prices have risen in the first quarter of 2012 compared with the same time last year, despite falling residential customer numbers.
The state-owned electricity generator and retailer says sales for the three months to the end of March rose 7%, boosted by a strong rise in the commercial market.
Residential customer sales volumes were unchanged in the period, despite aggressive competition driving down customer numbers by 5%.
The average energy price was flat compared to the previous quarter, but 5% higher than the same time last year.
The company says very dry conditions in South Island lakes pushed up wholesale market prices while strong rainfall in the North Island meant higher than average flows into Lake Taupo.
Higher generation volumes were driven by increased hydro and a big jump in gas fired generation, while the average generation price surged by more than 50%.
Mighty River chief executive Doug Heffernen says the company has held onto volumes despite a 5% fall in numbers as it targets higher electricity users outside of Auckland.
"As we've grown our business into the South Island, lower North Island and central North Island we're picking up customers who use on average more electricity per customer."
Last July, Mighty River forecast stronger full year earnings of $460 million to $475 million, reflecting drier South Island conditions and a fuller Lake Taupo.
The Government plans to sell up to 49% of the company as part of its partial privatisation programme which includes selling the same minority share of Genesis Energy, Meridian Energy and Solid Energy.
The Crown's shareholding in Air New Zealand will also be reduced.