3 November 1995

Far from new principle still has merit

ENERGY crops are a far from new concept on UK farms. They once accounted for two-thirds of the countrys arable land.

The crop in question was oats, to feed the millions of horses that constituted agricultures principal source of power.

Crops for energy still have merit, says Richard Crouch of renewable energy projects firm European Development Corporation.

He is confident EDCs proposal to build Britains first straw-fuelled power station near Ely will come to fruition. "Although we lost the most recent district council vote, it was a close run thing and the council has been advised that there is no sustainable reason for not granting permission."

The ambitious £40m project, in which regional electricity generator Norweb and construction firm Mowlem are now involved, is for a power station to supply Cam-bridge and the surrounding area.

It has also won a 15-year contract to supply premium-priced elec- tricity to the national grid under the Non-Fossil Fuel Obligation.

The plan is to use Danish furnace technology and "move the scale up a notch or two", explains Mr Crouch. "In Denmark straw-fuelled plants of this type are used principally to pipe hot water to the local community. Power generation would be our prime activity but a new glass-house nursery is an integral part of the project."

Much planning has gone into supplying the plant with the 175-200,000t of straw it would consume each year. Straw quality is a key factor. In addition to clearing land for the next crop it is another reason for the emphasis on baling rapidly behind the combine.

"Naturally, the straw needs to be as dry as possible. But we anticipate an average of 16%mc and could take straw up to 25%mc," says Mr Crouch. "With 16 bales burned in the furnace at any one time, the plant could cope with poorer-quality bales, provided they made up a small percentage of the burn at any one time."

Wheat straw, with a typical calorific value two-thirds that of coal, will be the principal fuel. But rape straw, with a slightly better calorific value, woodchips and forest waste are also candidates.

A by product of the plant will be about 8000t of potassium-rich ash. That is likely to go to a specialist fertiliser maker and ultimately back to the land. &#42

Getting to grips with straw for power… EDCs Richard Crouch.