A visit to Sutton Grange Farm and a meeting with Fred Walter gave us the opportunity to take a first hand look at the varied activities of the farm.
Sitting on the outskirts of Sutton cum Lound and Lound, the Walters have been farming at Sutton Grange for almost 100 years. They arrived before the extensive quarrying activities and farm around 2,500 acres. Whilst a good part of that acreage is devoted to what might be termed conventional farming there are crops and equipment on site that make this farm stand out from the rest. Sutton Grange farm is as entrepreneurial as they come operating the largest agricultural Anaerobic Digester in the country and growing and producing biofuels and at some time in the future, a solar farm.
On first sight it is hard to believe that such high end equipment and technological knowhow is housed on the outskirts of Sutton. This is cutting edge technology based on our very door step and not at all what you might expect to coexist alongside neighbouring Wetlands Lakes (Fishery).
Costing around £15 million pounds, commissioned in 2014 the plant with a nominal output of 1.4 MW is a joint venture with Tamar Energy Limited.
The Anaerobic Digestion process itself takes place in sealed vessels which contain microbes, specifically bred to break down agricultural waste. Feed those microbes with a prescribed diet of the waste in an oxygen lean atmosphere, keep them at the right temperature and as they consume they give off methane gas. It is important to provide the microbes with correctly balanced feedstocks, we witnessed maize which is a base feedstock, potatoes, onions, carrots on the feed pad on the day we visited and this is augmented with slurry prepared on a separate plant from chicken litter. The precise feed mix is controlled scientifically on a daily basis to maintain the diet that the bugs find acceptable and a daily consumption of 130 tonnes is typical. Digestion will take 30 days after which time the residues from the process both liquid and solid are collected and used as fertiliser on the farm. The methane off gas is cleaned up and used to fuel a pair of large gas engines which in turn drive alternators, producing electricity. The electricity is used on the farm, provides power to Charcon’s concrete plant which is situated over the fence and is also exported to the National Grid. Exhaust from the gas engines is utilised in a waste heat boiler providing process steam on the plant and a future addition will mean that the boiler exhaust will be used on a wood chip drier.
Wood Pellets and Wood Chip
Also based at Sutton Grange Farm is Coppice Resources Limited. This is a company also run by Fred Walter that specialises in the production of Short Rotation Coppice. This is mainly willow that is planted both on the farm and elsewhere that is harvested every 2 or 3 years, is sold as a carbon neutral biofuel. After harvesting, wood, be it willow pine or spruce is chipped and dried. The chips are either made available for power generation such as at Drax Powerstation or sold on to others to make pellets. In their pelleted form the wood fuel sold as fuel for domestic/commercial boilers.