A NSW Upper House committee holding a Parliamentary inquiry into the costs and benefits of rural wind farms was told yesterday that wind farms had the potential to produce at least 20 per cent of the nation's electricity.

Dr Mark Diesendorf, the deputy director of the Institute of Environmental Studies at the University of NSW, said yesterday that wind power was the cheapest of the non-hydro sources of renewable energy.

"It can substitute for some coal-fired power stations," he said.

"It can contribute at least 20 per cent of Australia's electricity and it can create thousands of new jobs, not so much in the operation, but in the manufacture of components."

However, the committee has also heard passionate objections from the Hunter Thoroughbred Breeders Association.

Michael Thew, who owns broodmare farm CrowningStone near Mount Moobi plateau, told the committee at an earlier sitting that his house was about four kilometres from a proposed turbine and he would have an "uninterrupted visual invasion of between five and 31 turbines".

The NSW Department of Planning is assessing plans for 42 wind turbines with a total generating capacity of up to 126 megawatts at an "energy park" at Scone.

Mr Thew said Scone Racecourse had a lot to lose.

"It is currently one of the most picturesque racetracks in Australia [and it] will have on its western vista the full array of up to 31 turbines on Mountain Station," Mr Thew said.

He also expressed concern about the impact on horses due to their sensitive hearing.

He was asked to estimate the value of livestock that may be affected, to which he replied about $500 million or $600 million.