For the first six months of this year, Otago's hydro lakes had the seventh lowest inflow from rain and melted snow since the 1930s, but the Electricity Authority says consumers did not face a power crisis because of regulatory changes it made.
Electricity Authority chief executive Carl Hansen said the two changes that had provided the biggest effect were the introduction of transparency measures for retail electricity companies and large industrial customers and a plan whereby customers are compensated when asked to conserve power.
Both of these changes have cut out opportunities for electricity companies to lobby for a public conservation campaign and ''have really altered behaviour'', he said.
Twenty-five years ago, New Zealand experienced one of its worst power crises.
In the winter of 1992, streetlights were turned off, people faced hot water restrictions and the country's major industrial power user had to cut consumption by a third. In 2001, 2003 and 2008, New Zealanders were asked to voluntarily cut electricity use in dry winters.
Mr Hansen said in this past very dry winter, power companies faced similar circumstances but there were much better outcomes.
He said introducing a scheme under which power companies would have to pay $10.50 per week to every household consumer if there was a public power conservation campaign, had given the companies an incentive to look after the lake levels.
''The choice the power companies always have if the rainfall is quite low and the lake levels are declining is when do they start up more thermal types of generation that run on coal or gas and do they run them early enough to to conserve the water in the hydro lakes.''
The Electricity Authority was established in 2010 and is an independent Crown Entity with a statutory objective to promote competition in, reliable supply by, and the efficient operation of, the electricity industry for the long-term benefit of consumers.
Mr Hansen said the Authority would undertake a detailed review of the past winter.
''There are always opportunities to learn from these experiences and we can't be complacent when dealing with the reliability of electricity supply,'' he said.
