Didcot Facility Aims to Prove Viability of ‘Gas-to-Grid’ Unit
By Rob Hull on October 6, 2010
A joint venture by British Gas, which is owned by Centrica, Thames Water and Scotia Gas Network to supply approximately 200 homes in Oxfordshire with renewable gas produced from human waste has opened this month amid concerns over its economic viability. The Didcot gas-to-grid unit is a pilot project to demonstrate the technology behind converting human faecal matter into gas for use in homes.
The Didcot facility faces a stiff battle for survival, however, as the proposed Renewable Heat Incentive (RHI) subsidy that was scheduled to come into force in April next year has yet to be approved by the coalition Government. In light of widespread public spending cuts, it is not unreasonable to assume that the subsidy, which also offers payments for heat generation using solar hot water heating, will be scrapped by the Conservative-Liberal Democrat administration.
Although converting human waste into usable domestic energy offers undoubted environmental promise, the cost is said to be far more expensive than traditional methods of gas production; in fact, energy companies predict that they are likely to require twice the market rate payment for renewable gas than they would for their standard products. In deciding whether the renewable gas ought to be subsidised, the Government must choose between economic and environmental concerns.
Renewable gas can also be generated from alternative organic sources, including supermarket food waste and breweries. On Friday, Adnams the brewer is set to open an anaerobic digestion facility in Suffolk that will generate renewable gas from waste slurry. The Adnams plant is expected to supply around 235 homes with the gas, which can be used in domestic central heating systems. The success of future renewable gas initiatives is also likely to hinge on Government spending.
The Didcot facility is designed to feed sludge – the solid component of sewage – through heated vats to stimulate anaerobic digestion, which occurs when bacteria break down biodegradable materials, releasing biogas in the process. The biomethane is then filtered for impurities before being supplied to the gas grid. Energy and Climate Change Secretary Chris Huhne remarked: “It’s not every day that a Secretary of State can announce that, for the first time ever in the UK, people can cook and heat their homes with gas generated from sewage”.