Initiative boosts anaerobic digestion expansion plans

Paul Boughton
Anaerobic digestion (AD), which transforms organic material such as food waste and manure into energy, could produce 7.5 per cent of the UK's renewable power by 2020, according to figures from the Department for the Environment, Food and Rural Affairs (Defra).

Defra has launched a task group to stimulate the development of AD technology among public bodies, businesses and farmers. This move follows the publication in February of an official report entitled Anaerobic Digestion - Shared Goals, which has been hailed as a major step forward by Hugh Richmond, director of sustainable power company ENER-G.

"AD is a viable, proven technology that is currently under-deployed in this country compared to other parts of Europe," said Hugh Richmond. "I very much hope the new government-backed task group will help to change attitudes and open people's eyes to the opportunities to AD, which can deliver huge commercial benefits, while helping to hit national targets on carbon emission reductions."

He believes the AD market will receive a substantial boost in April when the value of Renewable Obligation Certificates (ROC) for AD will become 'double ROC'. This government subsidy will significantly increase financial returns on each megawatt hour (MWh) of electricity sold into the national grid.

ENER-G has considerable experience of building, operating and financing major biogas projects across the UK and Europe.

The company is expanding its experienced team of specialist engineers to meet growing demand for methane-rich biogas projects, such as AD.

The company is witnessing demand from sectors such as agriculture, food processing and manufacturing, water and energy, and the waste industry, where ENER-G has significant experience in generating energy from landfill gas.

The company has installed and operates in excess of 120MW of biogas generation, primarily from landfill gas, which is of a similar variable quality composition to AD and utilises the same equipment. It has four 165kW biogas CHP units at South West Water's Countess Wear Sewage Treatment Works in Exeter, generating high value electricity from waste, while using the heat generated to service the site.

ENER-G's Hungarian subsidiary, ENER-G ENERGIA TECHNOLOGIA Zrt, is currently installing a EUR2.6 million, 4.5 MW biogas cogeneration project in the Budapest wastewater treatment plant. The project will go online in 2010 and serve some 1.5 million people. ENER-G will additionally manage long-term operations and maintenance services.

"The Budapest wastewater treatment plant is a strong example of how widely deployed AD is in many European countries," said Hugh Richmond.

Digestion plants produce a biogas which has high methane content of 50-70 per cent. This otherwise environmentally damaging gas is a rich fuel that can drive a combined heat & power (CHP) unit to generate both heat and electricity. The heat is used in the digestion plant as well as for heating in nearby buildings and the renewable electricity can be sold into the national grid at a premium price.

The UK currently produces more than 100 million tonnes of organic material annually from food waste, livestock slurry, sewage sludge and energy crops, which could be used to produce biogas.

The UK water industry treats around 66 per cent of the country's sewage sludge using AD technology. It plans to generate 0.8 TWh (terawatts) a year of electricity from AD by 2010. However, Hugh Richmond is endorsing the government's strategy to encourage much wider up-take.

ENER.G is based in Manchester, UK.

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