Days after consent for a farm near Dannevirke was denied last week, commissioners appointed by the Hurunui District Council also rejected a plan for a wind farm on Mount Cass in North Canterbury.

MainPower is planning to build a $200 million wind farm on the site and commissioners Paul Rogers, Paul Thomas and Dean Chrystal spent three weeks during November and December carrying out site visits and hearing evidence.

They found that the Mount Cass limestone ridgeline is an "outstanding natural feature of national importance which has significant limestone rock formations, native vegetation and habitats for native fauna" and denied the consent.

Mainpower now has 15 days to lodge an appeal with the Environment Court.

Contact Energy is also likely to take its case to court after its plans to build 65 of the largest wind turbines in New Zealand near Dannevirke were turned down.

Despite both applications getting rejected within days of each other, New Zealand Wind Energy Association chief executive Fraser Clark says the resource consent process has seen most wind farm projects approved in recent months and last week's two rejections were due to fairly unique circumstances.

"You only have to go back a month ago and two consents were granted at about the same time. The argument against the Mount Cass was mainly around some particular ecological features found in the area, while the Waitahora valley case was mainly over the unknown effect on local water quality."

Mr Clark tells NBR that wind farms are usually more environmentally benign because they need to be placed in elevated positions with little vegetation to produce the most efficient results.

This does not help the usual complaints of visual pollution whenever a new wind farm is proposed, which make up many of the submissions against wind farms, along with fears of increased traffic during construction, louder noise and the effects of the flickering shadows caused by the turbines.

Despite this, the Wind Energy Association is still keen to see the government improve the process for consenting large infrastructure projects, saying the consent process has caused significant delay which had a "very real impact on developers' decisions to proceed with new projects once consent is granted."

Delays caused by appeals of Meridian's Project West Wind, now under construction near Wellington, have been estimated to have added more than $100 million to the project's costs.

Mr Clark says the demand for new wind projects is on the rise, with all of the major power companies looking at wind options in conjunction with geothermal, hyrdro and gas generation.

"Over the past five years, the amount generated has grown from less than 100MW to more than 300MW. Wind is not the answer to everything and there is still a long wasy to go, but it's a free fuel source that nobody else wants."