The ministry publishes the document, which looks 25 years ahead, every three years. It has put up two scenarios for the next 25 years, each of which meets the criteria of being secure, environmentally responsible and affordable.

The first is New Zealand moving to largely renewable energy – biofuels for vehicles, and wind, geothermal, wave and hydro for electricity production.

That scenario assumes ocean wave power becomes available after 2015 at a cost of production of about 10.2 cents a kilowatt hour, a cost that is uneconomic at present.

The second scenario has plugged in hybrid fuel and electric cars and has New Zealand using Southland's vast stores of lignite coal to generate electricity. At the same time, the country would be using new carbon capture and storage technology to eliminate greenhouse gas emissions.

The first scenario has domestic electricity prices rising 13 per cent from 2010 to 2015, then falling a little and flattening out till 2030.

The carbon capture and storage scenario has electricity prices falling a little between 2010 and 2015 and then rising only 4 per cent over the 10 years to 2025.

Both scenarios assume that New Zealand achieves a 1 per cent a year reduction in electricity consumption for 25 years.