Muck to brass in project that converts plants to natural gas

A supply of plant clippings is all it takes for Irish company BioCore to supply enough gas for 7,000 homes in the UK. The Bray-based firm built a €20 million "gas-to-grid" plant that uses crop material from local farms in an anaerobic digester to provide a renewable energy source.

This is BioCore Environmental 's first facility in the UK, built near Suffolk, England. The company installed the plant, but in effect BioCore now becomes an energy provider, supplying pure biogas clean enough to inject directly into the UK gas network. It also has a gas generator, providing all the power needed to run the site but with the surplus diverted into the electricity grid.

The facility can provide enough gas for heating and cooking for 7,000 homes during the winter and for 120,000 homes during the summer when heating demand falls, says company managing director, Peter Carey. This equates to about 12 million watts of power.

"It is a major site and National Grid, the utility we are with, describes it as a significant site in terms of gas import," Carey says. "Our plan is to do another four in the UK along a similar scale."

Small electricity and gas suppliers in Britain benefit from a subsidy paid by the UK government. Renewable electricity suppliers receive a subsidy here but not gas suppliers, Carey says. The digester excludes oxygen in a process that breaks down the crop material, in the process releasing methane that is first cleaned and then pumped into National Grid’s network.

Plants of this kind produce renewable energy, helping to meet EU demands for green energy, says Carey. It also benefits the local farmers who now have a ready market for their “break crops”, plants put in as part of a farmer’s crop-rotation to maintain soil quality.

“We are located in a farming area and work with a group of farmers who feed the plant with break crops, like surplus maize and sugar beet,” he says. “Our plan is to do another four plants along a similar scale.” The company also has plans to install its first digester in Co Roscommon.

“It is one of the most efficient uses of biogas and reduces reliance on imported fossil gas, thus contributing to meeting the UK’s renewable energy and climate-change targets while improving energy security,” says Carey. The material left behind in the digester also contributes as a useful organic fertiliser.

BioCore was established in 2010. “We have three focus areas, renewable energy, sludge management and research,” Carey says. Its research unit has developed a treatment method to handle the leachate arising from landfill sites.

“It is a very exciting project, we are putting together a solution that can be used on site. We should have it ready this summer for a roll-out in the UK and Ireland.”

It would scrub the leachate leaving it clean enough to discharge as ordinary surface water, he adds. Currently it is transported to waste water treatment plants, but this technology would allow it to be dealt with on site.