Three years ago, we invested £17m to build our first Anaerobic Digestion (AD) plant, and are now using the knowledge we have gained about AD operations to supply AD operators across the UK with quality feedstocks.
Anaerobic digestion (AD) is the breakdown of organic matter without oxygen to produce flammable gases. These gasses can be burnt in an engine to produce heat and electricity, or cleaned up and used in the same way as natural gas, to heat our homes and cook our food.
In addition, in September 2018, our anaerobic digestion plant in North Yorkshire became certified to the PAS110 Specification for Digestate. Digestate is the waste material remaining after the completion of the anaerobic digestion process. This means the digestate from our plant can now be treated as a bio-fertiliser product, rather than waste. It can be spread on fields in exactly the same way as any normal fertiliser. The PAS110 certification applies rigorous testing to the digestate to ensure there is no contamination of heavy metals, plastics, metals or stones and that it is free of biological agents such as E'coli and Salmonella.
As well as reducing our waste significantly, we are also helping to reduce the use of fossil based fertilisers by helping farmers to switch to more sustainable bio-fertilisers.
We see this as a great example of circular economy within our business - taking waste from local sources to generate energy for the National Grid and converting the digestate from that process into bio-fertiliser supporting local businesses to become more sustainable.
Over the past 12 months we have generated approximately 35Gwh of bio-methane gas from almost 52,000 tonnes of waste – 44% more than the previous year. In the year ahead, we aim to run the plant at full capacity which will allow us to generate in excess of 40Gwh bio-methane gas for the local grid annually. This more than offsets the energy usage of three of our feed mills.