Mighty River Power, the country's fourth biggest power generator saw electricity sales and its market share grow in the last quarter of 2012, even as wholesale electricity prices fell.
The state owned electricity company said in a statement filed with the NZX sales volumes in the three months ending December rose 12 per cent to 1272 gigawatt-hours compared to the same period last year.
The gains came predominantly from business customers, with volumes up 22 per cent to 682GWh, with prices consistent with a year ago at $110.53 per MWh.
The firm said total electricity purchase costs fell 27 per cent in the period to $61.14 per MWh, reflecting lower wholesale prices and increased transmission capacity.
Wholesale pricing fell due to high inflows into South Island catchments operated by other power firms in the sector, denting the average price the company earned from its generation plants by 19 per cent to 66.25/MWh compared to last year.
MRP said this level still beat the market average, with its flexible portfolio of hydro, geothermal, and gas fired plants allowing it to respond to wholesale price movements quickly.
Total generation capacity rose 6 per cent into the period to 1154GWh, with hydro up 13 per cent, gas fired down 48 per cent and geothermal up by 0.6 per cent.
The sales figures come as the Government prepares to list MRP on the stock exchange in the first half of this year.
However, the process could run into headwinds from local iwi, who are seeking to overturn a High Court ruling which dismissed their objections to the sale of the state owned asset.