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From Grass to Grid

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Elean Power Station is a £60m plant located at Sutton near Ely in Cambridgeshire. It is the UK's first and the world's largest straw fired power station.

The power station was built between 1998 and 2000 and there are 50 people employed on site. The plant uses 200,000 tonnes of straw each year and generates enough electricity each year to meet the needs of 80,000 homes, or two towns the size of Cambridge.

The plant layout comprises two 18m high barns to house the straw either side of the 25m high boiler plant. To help the building fit into the surrounding landscape, it was built 8m into the ground. The heavy clay that was excavated was used to landscape the surrounding area which was planted with over 12,000 shrubs.

Straw and Lorry The straw is collected from farms within a 50 mile radius of the power station. It arrives in bales which each weigh half a tonne. One year's supply of bales would stretch from London to John o'Groats if laid end to end; and yet this would represent only 2% of the UK's surplus straw!

Delivered Straw Straw is delivered at the rate of one truck every half hour. The moisture content of the straw is automatically tested and must be below 25%. Cranes carry the bales from the trucks to the on-site barns which can hold a total of 2,100 tonnes, sufficient for up to four days of operation. Delivered Straw

Conveyor Belt Conveyor belts carry the straw via twine cutters and bale shredding machines to the boilers. There are four boilers and the straw is burned on a specially developed grate that maximises energy release and minimises emissions. Shredding Machine

Monitoring Machine The heat from the burning of the straw causes water to turn into high pressure steam. This is directed onto the blades of a turbine which is connected to an alternator to generate the electricity.

 

Water Pipes and Turbine

The burning straw is monitored

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The combustion gases released during the process are treated before they enter the atmosphere: they are neutralised by lime injection and passed through a bag filter to remove particles. The fly ash which results is rich in potassium and phosphate salts and is the basis of an organic fertiliser.

Emissions from the plant are up to 50% less than those expected from a conventional fossil fuel power station.