Wood fuel for thought

Today's energy policies are concerned overwhelmingly with generating electricity. But 84 per cent of the energy we use at home is to heat our rooms and hot water. What if that energy could come from a source which is not only renewable, but is cheap, readily available, and even improves the environment it is extracted from? Adam Nicolson reports on the growing potential for wood fuel in Kent

If you go out in the woods today you’re sure of a big surprise. Almost unnoticed, the total weight of the trees in the south-east is expanding by an estimated million tons a year – opening up the possibility of an environmentally sound solution to our energy needs.  Not only are the existing tree getting bigger, the number of trees is increasing and hedges are getting thicker.  As a result, a good percentage of the carbon dioxide being pumped out by our cars and our oil-fired central heating systems is being absorbed by the trees.

The growth of our woods provides huge benefits, including more cover for animals, a massive stimulus for invertebrate and bird life and a more extensive carbon sink. However, it is also a sign of failure and neglects.  Woods are no longer being maintained. In particular, the coppice woods of the south of England, which used to provide hop poles, fencing, hurdles and even the wood that was pulped to make paper, are being neglected.

There are thought to be more than 40.000 acres of coppice woodland in the south-east and a large proportion of those acres has been abandoned. The flowers that used to thrive around the coppice stools, when the wood was being cut regularly, are now finding themselves shaded out by a solid leaf canopy.

But, intriguingly, the world is beginning to turn back to what the trees can give us. As the price of oil and gas fluctuate wildly, the idea that wood might become one of the fuels of the future is enjoying a renaissance. And almost uniquely, as a fuel, its harvesting an create and enhance beautiful landscapes rather than destroy them.

'This is the dream fuel,' says Sara Kassam, sustainable development co-ordinator for the transformation underway around Ashford. 'It is good for the woods, the atmosphere and local employment, as the wood has to be managed. And it is good for your pocket, because the fuel is going to be cheaper than gas or oil in the future, and for fuel security.'

The technology may not be viable at the level of the individual house, but larger-scale institutions are suitable candidates. Ashford has commissioned a study of seven of these, including an office block, a public swimming pool, a leisure centre, a hospital and a housing estate. Each of the seven would require, on average, about 1,000 tons of wood a year. Local woodland owners and contractors would be paid £50 a ton and, if all seven schemes came off, more than 5,500 tons of carbon dioxide would be saved each year by the simple mechanism of the new trees re-absorbing the carbon that the burning wood released.

It is a closed loop. Except for the impact of chipping the logs and trucking the chips to the boilers – this vast amount of energy use would be almost carbon neutral.

Like mushrooms, the new wood-burning boilers are popping all over. However, the boiler cost two or three times as much to install as a gas or oil equivalent and the woodchips have to be stored undercover for at least a year before they can be burned if their moisture content is to drop below the necessary 30 percent. But the payback comes soon enough.

Nick Sanford, who runs the elegant 17th-century Godinton House near Ashford for a private trust, has commissioned a woodchip boiler to heat 3,000 sq ft of offices in converted farm buildings on the estate. He will burn chestnut chips from Godinton’s own coppice. 'I look at it this way: a ton of woodchips cost £45-£50. You get the same amount of heat from them as from 400 litre of heating oil. And that costs £165.”

Sandford expects to gather 75 tons of usable wood per acre of coppice once every 12 years. That shrinks to 60 tons when the wood is dry and his boiler will use 20 tons a year. In other words, to heat his offices he must have a wood of four acres and coppice a third of an acre each year on a 12-year rotation. The result: a beautifully manage wood, no pollution, money saved and fewer oil tankers. If the 40,000 acres of southern English coppice were put to this kind of use, there would be 30 million sq ft of English offices, schools, libraries, museums, houses and galleries that could be heated and watered in a way that was making wood beautiful. And what could be more admirable than that?

This article is reprinted with permission from the Watch on the Weald newsletter, published by the Weald of Kent Protection Society. Visit the WKPS website, at www.wkps.org.uk

This article first appeared in the Ecologist August 2007