SSE to begin building biogas plant

Scottish and Southern Energy (SSE) plans to start constructing Scotland’s largest biogas plant at a former landfill site at Barkip, North Ayrshire.

The deal makes SSE the first energy company in the UK to commit to construction and operation of an anaerobic digestion biogas plant of this type, which is expected to be operational by 2011.

The Barkip site will be capable of processing around 75,000 tonnes of waste annually, producing around 2.5MW of electricity that will contribute towards Scotland’s renewable energy targets.

Project partner William Tracey (a subsidiary of DCC) has signed a 25-year contract to supply feedstock materials for the plant, providing another outlet for their customers to divert waste away from landfill. Suitable materials will include waste foods, manures and organic effluent sludges.

The project was co-developed by Zebec Biogas, which has specialist enzyme and biological process expertise.

Anaerobic digestion is a natural biological process that uses bacterial cultures within enclosed silo tanks to generate methane-rich biogas from waste organic materials and energy crops such as grass silage. The Barkip plant will use a high-temperature thermophilic two-stage digestion process supplied by Danish technology firm Xergi.

The Barkip plant will be the first of its kind to incorporate a novel digestate processing stage. This will see heat being captured from the generation process and used to concentrate the liquid fraction of the digestate into a nutrient-rich liquid fertiliser.