We use a variety of feedstocks to produce home-grown green gas at our anaerobic digestion (AD) plants, including manure, farm waste, local food by-products, and crops.

Some people are concerned that using crops for the AD process is a waste when these crops could become food instead. However, this over-simplifies the diverse ways in which agricultural land is used. Growing crops as a feedstock for our AD plants supports farmers with managing their land and maintaining good soil quality.

Fuel versus fun

Not all arable land in the UK is used to grow food crops. Significant areas are now growing biodiesel for our cars, plus woodchip for our heating systems. In addition, 3% of our arable land is used to grow cereals for brewing and distilling (versus 2.1% which is used for energy crops).

It may come as a surprise that so much land is used to supply the brewery sector – more so than for biofuels and energy crops. This means that the question of land use is not really about food versus fuel – we refer to it as the ‘fuel versus fun’ question.

As the UK exports around 10% of its grain annually, it seems that no sector is undersupplied at present. So you can keep enjoying a good British beer without worrying about land management or supply chains!

Improving soil quality

A key part of our circular economy means the farmers who supply crops to our plants receive digestate in return (a by-product of the AD process that makes a great natural fertiliser).

AD crops are grown with natural digestate rather than synthetic fertiliser; this is starting to reverse the decline of organic matter content in the UK’s soils over the past 50 years. Intensive agriculture has caused arable soils to lose about 40 to 60% of their organic carbon. In contrast, AD cropping raises soil’s organic matter and this has two important benefits:

  1. Improved water holding capacity – leading to better drought resistance and reduced flooding
  2. Greater carbon storage – helping us reach Net Zero goals

Sustainable land management 

Crop rotation is an important part of managing agricultural land effectively, and incorporating an AD crop into the rotation has been proven to improve soil health and structure. Better soil quality means better crops can be grown in the next cycle – whether for food or fun.

Feedstock provider Troy Stuart explains how he grows maize for our Gorst Energy plant as a break crop, helping to improve soil quality for other crops in his rotation.

Using crops as a feedstock to help generate green gas is far from a ‘waste’. AD cropping plays an essential role in maintaining healthy soil so farmers can continue growing food sustainably.