Meridian Energy managed to lift operating profit in the year to June despite a "perfect storm" of low wholesale power prices, flat demand, fierce retail competition and earthquakes.
It was a robust performance in such a challenging year, chief executive Tim Lusk said.
Earnings before interest, tax, depreciation, amortisation and financial instruments (ebitdaf) rose 2.8 per cent to $659.9 million.
That was boosted by a one-off $28.1 million from settling - amicably, Lusk said - a dispute with Meridian's largest customer, Rio Tinto Alcan, over an outage at its Tiwai Pt aluminium smelter in 2008.
On the other hand, the Christchurch earthquakes cost the company between $20 million and $25 million in lost sales, as well as the costs of the disruption to its own operations, chief financial officer Paul Chambers said.