"The higher transmission charges reflect substantial investment in upgrading the national transmission grid and the higher distribution charges reflect the Commerce Commission's view that most distributors were earning too low a return on capital," he said.
"The competitive part of the sector - essentially covering generation and retailing activity - accounted for 28 per cent of the rise in retail prices over the past three years."
From 2004 to 2011 it was a different story, with 69 per cent of power price increases due to competition in the retail power market.
"A key driver of these increases were very sharp price rises for gas and coal, for example a 95 per cent increase in gas prices over the 2001-08 period," Mr Hansen said.
The Electricity Authority believed electricity prices would be relatively flat over the next few years, he said.
It would be difficult to know if the Auckland power crisis would affect regional prices, until the Authority completed a review, he said. This review will be sent to Energy and Resources Minister Simon Bridges by the end of April next year
In April, Tauranga Trustpower line and transmission charges increased by 5.5 per cent, while retail prices only increased by 3.13 per cent. Forty per cent of retail bills were line and transmission charges so this was no change to consumers, Trustpower community relations manager Graeme Purches said.
He said previous government-driven power upgrades had increased line and transmission charges.
Mr Purches said the past few months of the last term of the Labour Government signed off Transpower investing significantly in much needed upgrades to the National Grid. "Previously, the Labour Government had required maximum dividends from Transpower, having no money for these upgrades," Mr Purches said. "As a consequence, the belated planning and all of the upgrade work authorised by the Labour government had occurred and had needed to be paid for under the watch of the current National government."
Most retailers had reduced their margins because of competition, and households had become more energy efficient, he said.
"It doesn't look like there'll be big price increases in the next couple of years," he said. "It will probably plateau."
The average power cost was higher in the Bay of Plenty than in some other regions because of its distance from the national grid, he said.
Mr Purches believed the Auckland power crisis would not affect regional prices.
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