Ministers signal support for anaerobic digestion

The government yesterday outlined plans to ramp up the UK's use of anaerobic digestion (AD) technologies capable of generating energy, biogas and fertilizer from organic waste streams such as food and manure.

In a meeting with representatives from the agricultural, retail and water treatment industries, Defra ministers pledged to step up support for a technology that experts predict could ultimately generate enough electricity to power two million UK homes.

Anaerobic digestors work like small scale landfill sites, trapping methane from waste organic matter that can then be burnt off to produce heat and electricity or converted into biofuel. It also produces a nutrient rich digestate that can be used as a fertilizer.

The technology is relatively widely used in the water treatment industry where it is used to treat sewage, but experts insist that it could also have numerous applications across the agricultural and supermarket sectors. A recent study from property consultants Bidwells on renewable energy in the farming industry found that there was a strong case for installing anaerobic digestors at packing houses, where they could be fuelled by either waste food or slurry from local farms.

However, technical and commercial barriers have limited adoption of the technology. Greg Hilton, renewable energy consultant at Bidwells, said that the number of anaerobic digestors installed on agricultural sites "could be counted on one hand" and that projects still had a number of challenges to overcome.

"There is still a degree of risk with AD, because work is still going on to understand how best to manage mixed waste streams to maintain a consistent gas yield," he said, adding that with a large scale AD system costing upwards of £1.5m, access to funding could also be an issue for some firms interested in the technology.

Environment minister Phil Woolas said that the government was committed to tackling these barriers to adoption and would invest £10m in supporting a number of demonstration projects.

"Anaerobic digestion is still an emerging technology outside the water treatment industry in this country, and it's clear we are not yet making full use of its potential," he said. "It has a number of real environmental benefits which we want to maximise, but to do this we need to overcome certain barriers, like the chicken and egg stand-off which can discourage investment in unfamiliar technology, and the lack of understanding of its benefits or the value of its outputs."

He added that the government would be inviting bids for demonstration projects in the autumn, with a view to offering grants to between three and six projects capable of displaying a range of different benefits from the technology.

The £10m in funding is expected to be delivered through a capital grant competition run by WRAP and the Carbon Trust. A series of meetings are to be held ahead of the start of the bidding process to provide interested parties with further information on the types of projects that will be considered.

Hilton said that expected changes to the government's renewable energy incentive mechanism designed to offer greater support for AD projects would also help bolster demand for the technology. "It is widely understood the incentives will be increased and that will make a big difference," he said. "If you have the right waste stream it becomes a very commercially viable technology."