A major report into New Zealand's energy future finds demand for electricity will double and forecasts electric vehicles will make up 85 per cent of light vehicles by 2050.

And as fossil fuels are dumped as a way of powering industry, the Transpower-commissioned report found the equivalent of more than four big wind farms a year would be needed to keep up with surging demand.

By as early as 2030 electric vehicles (EVs) would make up 40 per cent of the fleet of more than three million light vehicles as they become cheaper to buy, run and have a longer lifespan than internal combustion engines.

The study predicted the country's peak demand risk would be exacerbated with growing demand being met from increasingly intermittent energy sources. One way of solving this could be a transtasman cable to import power from Australia — assumed to be generated from vast solar plants in the Outback.

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While new technology in this country would mean increasingly localised solar power and improved battery storage would ease pressure, under a base case scenario the equivalent of 4.5 wind farms with 60 turbines each would need to be built each year by 2050. This would meet the forecast 60 te ra watt hours of new generation needed to meet growth.

This assumes the retirement of some existing power stations, including all thermal plants which was in line with the current government's aims.

The report, done by Auckland firm Stakeholder Strategies based on work by government agencies and private research firms, warned that the right price signals needed to be sent.

''Investors might also be deterred if they are not confident about the stability of policy or regulatory settings.''

New power plants could cost hundreds of millions of dollars but localised generation would help offset this. It was estimated 1.5 million homes would have solar systems by 2050.

''Electrifying New Zealand's economy is arguably the biggest single economic and environmental opportunity facing the country. It also represents significant risk," said the 'Te Mauri Hiko - Energy Futures' report.

It said New Zealand could not sit back and be a follower of technology and innovation.

The report assumed the affects of climate change would continue to be felt but catastrophic consequences could be avoided by engineering solutions and co-ordinated efforts to cut greenhouse gas emissions.

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Not only would there be a mass move to electric vehicles, aircraft and ships could also run on batteries.

Transpower chief executive Alison Andrew said technological improvements in EV and batteries, more efficient electricity use and more renewable generation from wind, solar and geothermal would avert brownouts or blackouts.

Transpower chief executive Alison Andrew. Photo / Peter Meecham
Transpower chief executive Alison Andrew. Photo / Peter Meecham

''I'm confident if there is demand the industry has proven it can meet it with building power stations. There is a lot of consented wind out there and solar technology is coming at us very quickly. There is a huge technology push.''

She said there would be hurdles to reach, such as the forecast huge demand for EVs given price and availability. However, with more car manufacturers moving from petrol to electric affordability would improve.

There was no modelling done on power prices as a result of building new stations but big spending on the national grid for major new infrastructure would not be necessary.

Andrew said the grid was in good shape to cope with expansion following a $5 billion investment during the last decade.