State-owned Mighty River Power paid its first interim dividend to the Government - $56.2 million for the six months to the end of December - due to a strong performance for the period.
But chief executive Doug Heffernan warned that after the higher than expected profitability in the first half, poor hydrology in the Waikato in the past few months had brought the company's profit back in line with expectations.
Since November inflows into the Waikato River catchment had been only 80 percent of average.
Mighty River, which operates the nine-station Waikato hydro system and geothermal plants around Taupo and Bay of Plenty, reported a first half net profit of $73.9m.
That was up from $30.7m the previous year when the company had a $118.8m charge for a change in the fair value of derivative financial instruments, mostly related to interest rates.
In the dividend announcement today, Mighty River said the interim dividend was the first in the company's history and recognised the strong performance of the company during the six-month period and its stable financial position.
Mr Heffernan said when Mighty River directors finalised the statement of corporate intent in June last year they decided it was now in a phase where it could pay an interim and a final dividend.
That replaced the previous policy of paying just one dividend at the end of the financial year, and gave the Government the cashflow benefit of receiving some dividend payment after the half-year result.
The policy had also changed to now pay 75 percent effectively of profit as dividends.
That portion had risen over time to reflect the strength of the company and had been 60 percent a year ago, Mr Heffernan said.
The shareholder had been prepared to receive a low dividend when the company had an extensive programme of capital spending under way. Now cashflows coming into Mighty River were much higher and it was no longer building two geothermal projects at the same time.
With the Nga Awa Purua geothermal power station, near Taupo, becoming fully operational today, Mighty River now had two large geothermal stations running, with the revenues flowing in.
Nga Awa Purua, a joint venture between Mighty River and the Tauhara North No 2 Trust, was finished ahead of schedule and will have a total capacity of 140 megawatts (MW), compared to 132MW originally planned.
Mr Heffernan said the station, part of a $430m project, would run continuously and contribute to the country's long-term security of electricity supply.
It produced enough energy to power around 140,000 houses, equivalent to every home in Taupo, Rotorua, Hamilton and Tauranga.