Up to a fifth of future electricity needs can reliably come from wind farms, Government-commissioned research shows.

As part of a push for a big expansion in wind generation, the Government says it shows that the potential for wind energy is greater than previously thought.

The research, "Wind Energy Integration in New Zealand", by the Ministry of Economic Development and the Energy Efficiency and Conservation Authority, looked at how easily new wind farms could be plugged into the power system.

It explored a serious criticism of wind power - its fluctuations and related strain placed on the national grid and power dispatch systems.

It did not address one of the biggest challenges facing wind power growth: community opposition under the Resource Management Act.

Energy Minister Trevor Mallard said no special rules would be made for granting wind-farm consents.

"It is also important to note that there are challenges in integrating wind power that are yet to be resolved."

"Large swings in generation output" have already been reported at existing Tararua wind farms by national grid operator Transpower, which says new investment in lines such as its proposed $500 million one running through the Waikato is needed for new generation such as wind farms to be viable.

The chief executive of the Wind Energy Association, James Glennie, said the total amount of electricity generated nationwide last year was 40.5 billion kilowatt hours and the report said 8.3 billion kWh could come from wind power.

About 2000MW of wind capacity could be installed without compromising the reliability of the national grid.

This is the equivalent of two Huntly power stations - the country's biggest single power plant.

Technical problems associated with generating electricity from wind that were previously described as "show-stoppers" were now being addressed by rapidly evolving technical advancements.

Glennie said new wind farms increased the system's hydro capacity.

When wind was generating electricity, water from hydro lakes was being saved.

* State-owned power company Genesis is this week fighting an appeal in the Environment Court over a 19MW farm on the Awhitu Peninsula near Waiuku, south of Auckland.

Local residents had the project stopped last year, citing the appearance of the turbines and the effect on nearby horses.