High on an environmentalist's wish-list would be a power source that delivered unlimited amounts of power while producing no pollution and little or no carbon dioxide. Impossible, many would say, but a new research project at University College, Cork aims to provide just such a power source.

The approach is based on combining a renewable energy supply, the wind, with a fuel cell, a device that burns hydrogen and air to produce electricity, heat and pure water. The project's promoter is Dr Eamon McKeogh of the Department of Civil and Environmental Engineering at UCC and head of the sustainable energy research group there.

A key element of the project was the fuel cell, he said, which was generally "considered the energy sector of the future. It is really the zero emission scenario." This is a comprehensive research initiative, however, involving other teams and disciplines.

Dr McKeogh has joined forces at UCC with Dr Michael Egan of the Department of Electrical Engineering, who will develop the electrical and electronic control system which will handle and regulate the building's power supply. Together they have won a two-year grant, worth £500,000 (€634,869), from the EU's Marie Curie Fellowship programme.

Separate to this, Professor Declan Burke of the Department of Chemistry is looking at the fundamental science behind the chemical reactions that take place inside the fuel cell. These depend on the use of "catalysts", substances that help the fuel cell reactions along without being used up themselves. Enterprise Ireland and the Higher Education Authority fund his work at UCC.

Fuel cell technology is being pursued vigorously by researchers in other countries, notably the US and Japan. US teams have sunk at least $1 billion (€938 million) into this subject over the past 30 years and similar amounts have been spent in Japan. Their interest lies in the fact that fuel cells can produce electricity both cheaply and cleanly and could offer an alternative to both fossil fuel power stations and to the petrol or diesel engines in our cars.

We won't have to wait long for these new energy supply systems; six of the world's top 10 car manufacturers have committed to having production line fuel cell-powered vehicles on the market by 2004.

These companies point to the higher fuel efficiency of fuel cells and to the near elimination of many of the pollutants which come from conventional car engines. They will undoubtedly use this to promote their "green" credentials, even though the type of fuel cells they will employ will still give off large amounts of carbon dioxide.

Dr McKeogh's approach is the ultimate in "green", however, converting free energy from the wind into electricity and boosting this with a fuel cell which will provide all the heating and hot water, extra electricity when the wind isn't blowing and releasing clean, pure water as its only "chemical" discharge. There is no carbon dioxide, no smoke and no waste by-products.

The plan developed by Dr McKeogh and Dr Egan is to provide all the power, heating and light required for a proposed 200,000 sq ft "green building" which would be built on campus and be used as a centre for environmental research. It would need no connections to external power supplies and would be self-contained in terms of its own energy requirement.

A ball-park figure for this system's cost would be about £530,000 including £200,000 for a 250 kilowatt wind turbine, £100,000 for an "electrolyser", which is explained below, £80,000 for a commercially available fuel cell and £150,000 for the development and implementation of the electricity control systems, Dr McKeogh explained.

The backbone of the system is the turbine which would deliver the bulk of the building's day-today power requirement. While we do get plenty of wind in Ireland, it doesn't blow all the time or it blows at night when the power isn't needed. The fuel cell helps bridge this gap.

Like a standard battery, fuel cells use an internal chemical reaction to deliver electricity, but unlike batteries, they don't run out of power. Fresh supplies of chemicals are added all of the time to maintain the chemical reaction.

There are five main types of fuel cell and they burn many different types of fuel. The fuel used dictates what type of discharges they produce, but in the main they are 10 per cent to 20 per cent more efficient than standard electricity production if power line transmission losses are taken into account. They could also be made very small and so could be used as a local power supply, Dr McKeogh said.

The car manufacturers are planning the use of fuel cells that burn methanol, a form of alcohol that has a single carbon atom. It delivers electricity at 40 per cent efficiency and would eliminate sulphur and nitrogen pollution but would still discharge large amounts of the greenhouse gas, carbon dioxide.

Dr McKeogh's plan calls for a fuel cell that consumes pure hydrogen, a limitless source of energy that can be got directly from water. For those who remember any basic chemistry, an electric current can be used to split water into the gases, hydrogen and oxygen. Dr McKeogh's system will use night-time or excess electricity from the wind turbine to power the electrolyser mentioned above to create and store pure hydrogen.

If there is too little wind, the fuel cell can then use this stored hydrogen supply and oxygen from the air in a chemical reaction which is the exact reverse of the electrolyser. The two gases are recombined to form pure water and, in the process, both electricity and large amounts of heat are produced.

While a standard fuel cell works at about 40 per cent efficiency, this system would work at near 80 per cent efficiency because the heat would be captured and used for heating and hot water. This would be boosted by the use of heat pumps which work like refrigerators only the other way around, taking away cold and emitting heat instead.

The electrical control system would be complex. Fuel cells produce direct current, not the alternating current in our homes and offices. A number of cells would have to be stacked to boost the DC current and this would then be converted to AC for the building, Dr McKeogh explained.

The result, however, should be a building that has total control over its energy supply, a supply that would be delivered free on the back of the wind. It doesn't get environmentally greener than that.