Crouchland Biogas application makes much of how green and sustainable the operation is . If it was to stay in its original form as a small scale AD plant producing energy from it's own dairy farms slurry and manure then most would agree that it would be considered green. However the huge expansion in size means that it needs to import 40% of what's needed to feed the digester.
32% of the inputs consist of maize (11,140 tonnes) which will be grown specifically for them and imported from other farms. Growing of maize for energy is in itself controversial and several key opinion leaders point out that it makes no green sense as it takes up valuable land that could be used to grow food crops and that the carbon dioxide release of growing maize can result in "carbon released to power produced ratios" comparable to some coal fired power plants.
This extract from an article by George Monbiot in the Guardian looks at some of the issues Germany has faced with the growing of Maize for energy
you want to know where we might be heading, take a look at Germany. Two years ago Der Spiegel reported:
"Subsidies for the biogas industry have led to entire regions of the country being covered by the crop … Plans called for transforming Germany into a bio-wonderland by peppering it with numerous small eco-power plants. What resulted was a revolution in the fields, a subsidised gold rush – and an ecological disaster. Corn [maize] is now being grown on 810,000 hectares in Germany."
As a result, "for the first time in 25 years, Germany couldn't produce enough grain to meet its own needs."
On some soils, the German Nature and Biodiversity Conservation Union estimates: "growing corn releases 700 grams of carbon dioxide into the atmosphere for every kilowatt hour of energy it produces. And this happens for years on end. This is comparable to the carbon-released-to-power-produced ratio of some coal-fired power plants."