Case Story Ireland

MONO-DIGESTION OF CHICKEN LITTER

TULLY BIOGAS PLANT, BALLYMENA, NORTHERN IRELAND

January 2019

MISSION AND VISION

The Tully Biogas Plant (figure 1), located near Ballymena in Northern Ireland, is one of the first facilities in the world that generates renewable energy from chicken litter as the sole feedstock using an innovative combination of anaerobic digestion and nitrogen stripping technology. With a construction cost of £23 million this plant represents a major investment for Northern Ireland and delivers several benefits to the community, in the form of local jobs, renewable energy and recycling of nutrients. The biogas plant processes up to 40,000 tonnes of locally sourced chicken litter each year and generates 3MW of renewable electricity which is enough to power 4,000 homes. The plant was developed by Stream BioEnergy and was co-financed by funds managed by the UK’s Foresight Group and Invest Northern Ireland. Xergi, a Danish specialist supplier of large scale biogas plants, was responsible for the design and delivery of the plant and is also a shareholder in the project. Xergi is also responsible for the operation of the plant.

BENEFITS OF THE FACILITY

Employment and Services: The plant employs 12 full time members of staff for operations and many off-site jobs have been created through a range of professional services that the plant requires. Local companies in Northern Ireland were appointed to deliver engineering and construction services and, during peak construction, up to 50 people were working on site.

Poultry Sector Benefits: Where excessive nutrients from chicken litter are spread on land they can cause pollution of watercourses and have a negative impact on the environment. Action to address nutrient enrichment of watercourses is required by both the EU Nitrates Directive and the EU Water Framework Directive meaning a more sustainable way of managing chicken litter is urgently needed. The Tully Biogas Plant is helping to achieve that at a local level through this innovative combination of technologies. The plant is fed with poultry litter from over 100 farms around the Ballymena region thus providing local farmers with a safe outlet for the disposal of the litter. In this way the innovative Tully Biogas Plant provides the Northern Ireland poultry industry with a solid foundation to support its continued economic growth, which in turn creates more employment and increases the gross output of the agricultural sector.

Renewable Energy Generation: Biogas is a valuable product of AD which will play an important role in helping to achieve Northern Ireland’s EU Renewable Energy Targets for 2020 and beyond. The biogas generated at the Tully facility is converted to electricity (3MW) which is exported to the national grid. The plant provides a constant stable supply of renewable electricity to the grid delivering energy security of supply benefits. It also further diversifies the national fuel mix and reduces the country’s reliance on fossil fuels.

Climate Change Benefits: The Tully Plant plays an important role in the fight against climate change as it reduces Greenhouse Gas Emissions (GHG). Landspreading of litter generates uncontrolled emissions of GHGs to the atmosphere as the waste degrades. By diverting this litter to AD the organic materials are processed in an enclosed system which prevents the uncontrolled release of methane. Replacing fossil fuels with renewable energy generated in this manner also reduces GHG emissions.

Production of Biofertiliser: AD not only recovers energy from organic waste, but it also produces a nutrient rich digestate that can be used as an organic biofertiliser. The nutrients contained in digestate are more amenable to plant uptake than other organic fertilisers and thus its use has water quality, environmental and health benefits as it decreases organic pollution potential as well as reducing risk of spreading microbial contamination.