Soon to be partially privatised Mighty River Power has seen a 29 per cent jump in commercial electricity sales in the June quarter.
The government intends to sell a 49 per cent stake in MRP, though the timing of a share float is not certain yet, though it has been previously signalled for September.
The government announced yesterday that Kiwis with $1000 or more to invest would be targeted for the MRP share float.
In a quarterly business update, which did not include any profit figures, MRP said total customer sales volumes were up 12 per cent in the June quarter, including the big lift in commercial sales.
For the full year sales volumes were up 5 per cent, despite customer numbers dropping by 6000 during the year.
"The growth in sales volumes was driven by our continued strong sales performance - with a 29 per cent lift in commercial sales volumes and a 14 per cent lift over the 12 months," chief executive Doug Heffernan said in a statement.
However, total generation volumes fell 145 gigawatt hours, or 8 per cent, in the quarter.
Hydro power generation was down almost a quarter from the extremely high levels seen last year when there were extraordinary water levels in the Waikato River catchment which feeds MRP's hydro power stations.
Wholesale electricity purchase costs jumped from $47 a megawatt hour to $113MWh in the quarter, while generation prices increased from $45MWh to almost $100MWh.
Low lake levels in the South Island and constraints on capacity to move power between the North and South Island saw higher wholesale prices in the South Island in the quarter.
MRP said its total generation volumes fell 8 per cent in the quarter, reflecting the drop in hydro generation.
"Inflows to the Waikato River catchments were not at the extraordinary levels of Autumn/Winter 2011, which explains the large fall in volumes quarter-on-quarter following a strong first nine months," Heffernan said. Hydro power still accounted for the lion's share of power production, at 905 GWh in the quarter.
Gas-fired generation volumes were up significantly - with a more than five-fold increase for the quarter to 179GWh as MRP used its Southdown gas-fired plant to take advantage of the high wholesale market prices.
Geothermal generation was broadly flat at 556GWh with the impact of the sale of a 10 per cent interest in the Nga Awa Purua plant in early April, mostly offset by high availability factors across geothermal stations of 99.7 per cent.