John Gilliland is a renewable energy farmer, but he is not your regular good-lifer or bowler hat who has decided to espouse alternative energy. He returned to Derry from the University of Edinburgh in 1989 to take over the running of Brook Hall estate, a large agricultural holding within the city limits and on the banks of the river Foyle.

The 650 acres of the estate - which is in four blocks over 22 miles - had been let out in conacre. Mr Gilliland, who had just got his agriculture degree, is the fifth generation of his family at Brook Hall, but his father was a lawyer, not a farmer, which is why the land was let.

"As a young farmer, even then, it was very difficult to get into the industry. I didn't have milk quotas and finance charges were very high; the cheapest way was through tillage. Part of my inheritance was the estate. There was my father's house and 35 acres of gardens. The biggest challenge to the farm was to create an income to maintain the estate," he explains.

In tandem with running the farm he set up an agricultural contracting business, and in 1991 won the all-Ireland tillage farmer of the year award.

By 1995, he started to look at biomass as a means of generating energy. Having started with a trial five acres, he had 110 acres set aside under short rotation willow trees by 1996. And with his company, Rural Generation, he became the first farmer in Europe to set up a commercial combined heat and power project to process the wood.

"Everybody thought I was barking mad, but then they said 'he has just won the tillage award'. People quickly got to see me as a businessman with a good head for the economics of farming. Now, five years down the line, we are beginning to see an interest," he reports.

One-third of the willow coppice is harvested every year and is chipped and dried during the winter months. The chip is fed into a gasifier, which produces gas. The gas is then cleaned up and fed into a diesel engine.

"With 10 per cent diesel and 90 per cent gas, we drive a generator that produces electricity but we also collect the heat from the radiator of the engine and from the exhaust of the engine.

"The heat then dries all the grain on the farm, dries the wood chip on the farm and heats my father's house and my house - we have a district heating system underground that distributes hot water around the whole of the estate.

"The reason we do this is about efficiency. If I was only to utilise the electricity, we would be at best 32 per cent efficient, converting fuel into electricity. But by capturing the heat and utilising it as well, the overall efficiency is more in the order of 70 per cent.

"All my electricity is sold to Northern Ireland Electricity under a 15-year non-fossil fuel contract. I am putting in 100 kilowatts - enough for 30 houses," he explains. Combined heat and power plants are three times more efficient than straight generators, he points out.

And the whole concept - where crops are grown locally and the farmer owns the power plant and sells heat and electricity into the local community - fits very well into the EU's "second pillar" rural development plans.

Apart from the main project, Rural Generation is involved in White Oaks, a cross-Border project multi-fuel heating system in a rehabilitation centre near Derry city. Together with the Department of Agriculture, it has planted 10 acres of willows as a biofilter to take the dirty water from Derry's sewage treatment plant.

"In Sweden, initial research shows willows can remove 95 per cent of phosphates, nitrates and heavy metals. One of the biggest environmental issues is phosphates in water. One of the ways of reducing the amounts of phosphates coming into the water from agricultural land is to plant buffer strips of willow coppice along river tributaries.

"We're looking at developing and sustaining the rural community, to bring the rural partners together again. It's a win-win situation. It brings the community together, keeps money in the rural community, sustaining jobs and very much sustaining the environment," he adds.

"What drives me in everything I do is that I want to take the whole rural and agri-food debate to the general public in a positive and constructive manner to show the general public how actual farmers could be the salvation and not the pariahs of society and how, through innovative measures, we could clean up their waste. Through these kinds of projects, there is tremendous potential for the farmers to be seen as the people who create solutions for the environment and are given the right encouragement by society, which they are not getting at the moment."

To attract farmers to the idea, however, the bottom line is going to be important. In Mr Gilliland's experience, biomass is a highly profitable enterprise.

"By converting willows into heat and power, I am getting £300 a hectare. At the moment, on my farm, that would be probably four times better than tillage. Government grants for short-rotation coppice have gone up to £1,000 an acre for arable land and £1,600 an acre for grassland.

"The profitability of agriculture in the North is dire at the moment. It's not difficult to find an alternative land use that provides a better income. The beauty of the project is that my enterprise is an enterprise in the existing farm business. It shares the existing fixed costs. We harvest in the winter when we're twiddling our thumbs. The peak work requirement is spread more evenly. There is tremendous synergy within my business."

But, he says, while there is interest in what he is pioneering - the Department of Agriculture is the only other grower - farmers are slow to change.

"The way to catalyse change is through a period of pain and there is that period of pain in the North at the moment." He is careful not to appear fanatical in persuading others to follow in biomass "like the organic movement, where they rubbish conventional agriculture to the betterment of their own".

He exhorts farmers to "see how it fits in with conventional agriculture and see how it helps conventional agriculture and shows to the outside world how agriculture can find the solutions for society. That may be a very holistic, very aspirational, very naive view but, somewhere along the line, we have got to tackle it. I may live to regret it but at least I will pass away with the knowledge that I have tried."

Mr Gilliland already has a very public profile through his liaison work between the Ulster Farmers' Union and the Department of Agriculture during the recent foot-and-mouth crisis. He will soon be in a stronger position to promote his ideas on renewable energy and its place in rural development. He is currently deputy president of the Ulster Farmers' Union and takes over as president in April.

Because of his work there and his work as a commissioner to British Prime Minister, Tony Blair, on biotechnology and as director of the Home Grown Cereals Authority in London, he has had to employ an assistant farm manager.

"I used to be totally hands-on. I can't be now. When things are really down psychologically and there is a lot of pressure on me, there is nothing better than getting onto a tractor and ploughing 20 acres. It's a great release. Just getting three hours to walk around the farm and look at crops, its different. I can't relax. I have to do something."