AN engineer has devised a unique system to convert the power of the wind directly into heat in an invention which could rid the roads of frost in the winter and allow certain crops to be grown for 365 days a year.

Andrew Mackay, 63, said his new method - which converts the kinetic energy in the wind - could solve many local energy problems in Scotland through the medium of renewable heat.

He believes one of the systems could heat up to 250 acres of farmland while it could also generate electricity, giving farmers a "new and lucrative" income stream by allowing them to sell electricity to the national grid.

"It can be used to heat water in a house or other buildings for radiators or under-floor heating," he said. "It could heat housing developments, hospitals, or distilleries which use vast amounts of heat.

"These devices placed every five miles adjacent to the A9 with pipes running along the verges would keep the road frost free for ever more.

"I have got a farmer in Aberdeenshire very interested in it. It is buildable now using common construction methods and materials although the wind-to-heat converter would need to be precision engineered and balanced."

The patented Gentec AS Renewable Heating System's first step is for the wind to rotate anemometer type cups mounted on a horizontal shaft. In turn, the mechanical shaft power is converted into heat, by driving a form of direct current (DC) generator. The faster the wind blows the more power goes into the system.

The electrical power passes through specially designed industrial immersion heaters that can handle huge variations in currents running through them.

These are immersed in a propriety heat transfer fluid bath made of heat conductive concrete that forms part of the converter's base which can be heated up to a maximum of 400 degrees Celsius. This acts as the primary thermal store.

Mr Mackay, a Ferranti-trained electronics engineer, said: "If you have wind blowing at two metres a second, which is a low wind speed, it will turn the shaft. Every time the wind speed doubles there is eight times more thermal power going into the system."

He said if too much power was generated, the system would automatically shut down.

But he added: "There is also the option to generate electricity as a by-product, from the thermal store to power the farmhouse 24/7 and upload surplus electricity onto the Grid giving hard-pressed Highland farmers a new and lucrative income stream."

Mr Mackay said the optimum surface temperature for growing grass and other crops in Scotland varied between 15 and 20 degrees Celsius.

"Water is pumped through at the bespoke temperature for any particular crop," he said. "This opens up the possibilities of growing more exotic crops."

Mr Mackay, who runs Andrew H Mackay Limited in Tain which specialises in providing renewable heat solutions for agriculture and commercial businesses, said the system was not solely dependent on Scotland's windy climate and it would continue to work if there was no wind for days or weeks.

"The primary thermal store will carry on providing heat and green electricity unabated for two to three months," he said.

He said it was impossible to say how much each device would cost. "That would depend entirely on what the individual farmer needs from it," he said. "It would vary from farm to farm."

It comes as a consultation on land reform is under way, with a view to finding ways to promote sustainable development in rural communities.

A Scottish Government spokeswoman said it welcomes all views on the issue of land reform.

She added: "We would encourage all those with an interest in the matter to respond to our ongoing consultation which closes on February 10."