The warmest June on record led to a 12 per cent fall in power demand from Genesis mass market customers in the month, compared with a year ago, while a broker says the whole electricity market is facing "excess supply and sluggish demand".
In its June quarter operational report, Genesis said total retail electricity sales were down 3 per cent in the three months and it had been losing market share for both electricity and gas customers in the past year.
But the company has seen a big lift in "time of use" electricity sales and gained a boost from increased oil and gas production from the Kupe field in the June quarter.
During the day, Genesis shares reached $1.83, close to the $1.81 seen when it first listed in April. The shares were issued at $1.55.
A report by Morningstar rates Genesis shares a "hold" and notes that the "oligopolistic" market creates significant barriers to potential new entrants.
That means Genesis and other existing energy companies are expected to make returns above their cost of capital in the long term.
However, Labour and the Greens plan to regulate the power sector to bring down retail prices; this would hurt all electricity companies.
"Also, the medium-term outlook for the electricity sector is not very promising because of excess supply and sluggish demand, which will temper operating income growth in the next few years," Morningstar said.
In the June quarter, Genesis said, mass market power volumes were down 9 per cent, which more than offset a 55 per cent lift in "time of use" electricity sales.
"Time of use" plans charge a different rate for each half-hour period of each day of each month, rather than a fixed rate for each unit of power, regardless of the time it is used.
Genesis's "time of use" sales are increasing and accounted for 15 per cent of total electricity sales in the June quarter, compared with 9 per cent a year ago.
But the report also shows that Genesis has been losing electricity market share, with customer numbers down 4 per cent in the past year to about 523,000. Gas customer numbers were down about 3 per cent.
Genesis said the falls reflected increased competition for electricity customers and more "niche" power retailers. Most of the customers were lost in the North Island.
Significant rainfall from mid-April in the South Island, coupled with "unseasonably warm weather", led to a sharp fall in the wholesale electricity price for most of the fourth quarter.
The average price at the Huntly node was $70.90 a megawatt hour, down 8 per cent on the same period last year. For the full year, the average price was $69.69 a megawatt hour, down 5 per cent on the previous year.
Meanwhile, production of oil from the Kupe field was up 5 per cent in the June quarter to 146,000 barrels compared with the same period last year, to take advantage of higher global oil prices.
There was also a 23 per cent lift in gas sales and a similar lift in sales of LPG.