Straw power plant rides out fuel and cable snags
FOR a power station to be shut down through lack of power is about as ironic as the plight of the ancient mariner surrounded by water, with none of it fit to drink.
But that is precisely what happened to the £60m, 36MW straw-fired plant at Ely run by Anglian Straw, after an Eastern Electricity cable joint failed.
The incident was the latest in a period which tested the fuel-from-the-fields idea to the limit, says operations manager, Neil Bond.
Technically the UKs first and worlds largest straw-fired plant, built by Danish company FLS Miljo, had run "as sweet as a nut" until the Oct 3 power failure.
Farmers supplying it can either bale the straw themselves or let Anglian do the job. Only Hesston big bales are suitable, prices ranging from £1-£1.50 a bale if baled by Anglian to £20/t, index-linked, for long-term farmer-baled contracts. Over 200,000t of straw a year is required from within a 50-mile radius.
"We have learned a lot of lessons about getting supplies, not least about access," says Mr Bond. "We began generating at the end of last December in the wettest weather for 200 years, which was hardly an ideal start." Moisture content for efficient combustion must be less than 23.5%.
The sites 2100t storage barns provide a 76-hour buffer but need regular refilling. Wet weather meant hauliers found it hard to get to farm stacks, which meant extra expense, for example laying metal trackways. We even ended up with a 360í excavator with a grab to help out.
"We have now built a lot of hard standings like those for sugar beet, using some of the ash from the process to build them. They will be a real boon."
Economic spur to the station was a contract until 2013 under the governments NOFFO 3 renewable energy support scheme.
"That boosts the electricity price to help get green projects off the ground and fulfil the governments Rio and Kyoto commitments. This gives the project the necessary stability to attract private finance," says Mr Bond.
By 2013, when income from selling electricity falls, all loans should have been paid off and the plant should remain financially viable for the rest of its minimum 20-year life, he adds.
Most straw used so far has been from combinable crops, mainly cereals. But the plant is designed to take other crops. "We have already used miscanthus from ADAS Arthur Rickwood," says Mr Bond.
Discussions are also under way to make use of the low-grade waste heat lost to the atmosphere. "We are on an industrial estate and have planning permission for 20 acres of glasshouses. But we are not horticulturists."
Getting planning permission, meeting Environmental Agency requirements and satisfying objectors was an uphill battle largely won, he believes.
Over 250 local people visited the site at a recent open weekend. "I do not think anyone went away unhappy with what they saw." *
Supply lessons aplenty from the first years working, but Anglian Straws power plant puts £4m-£5m a year into farmers pockets, says Neil Bond.
Ely straw plant revolves around Hesston big bales, here being off-loaded for use in the two-stage furnace.
• Tricky but successful first year.
• Wet weather lessons learned.
• Beet-style hard standings boon.
• NOFFO contract essential.
STRAW POWER STATION FACTS AND FIGURES
• Only Hesston big bales.
• £1 a bale to £20/t index-linked for long-term contracts.
• £4-£5m a year to agriculture through straw purchases.
• Enough power for two towns the size of Cambridge.
• Burns wide range of bio-fuels, including all cereal and oilseed straw & miscanthus, and up to 10% natural gas.
• Most supplies bought from within 50-mile radius.
• Up to 50 long-term jobs.
• Bottom and fly ash used in hard standings & fertiliser.
• Waste heat for possible horticulture project.