These mobile small stations would have a combined capacity of 35MW and would initially be located on Christchurch industrial sites, but could be moved to other parts of the country in the event of major earthquakes or electricity grid failure.

Orion chief executive Roger Sutton said the stations would be offered to the government as part of this country's new dry-year generation reserve, but might also run during winter peak load times.

Last May the government decided to establish the reserve generation capability for when hydro lake levels are low or network disruptions send wholesale power prices past the $NZ200 a megawatt-hour (MWh) mark.

The government is paying Contact Energy $NZ150 million to build a 155MW diesel-fired station, probably at Whirinaki near Napier, though the newly-formed Electricity Commission will take over that plant and others as part of arranging 400-500MW of reserve thermal generation capability over any four-month winter period.