There is an urgent need to reduce greenhouse gas emissions, but is one possible solution to climate change damaging the natural world? Miles King investigates.
Maize grown to produce biogas now covers 57,000ha, which is enough land to produce 2.8 million tonnes of potatoes. That’s equivalent to providing 43kg of potatoes for everyone in the UK. So this is a large area of land, which could be producing food, but instead is producing biogas.
Maize is also one of the most environmentally damaging crops grown in the UK, especially when it is grown on steep slopes or near rivers. This is because when there is heavy rain in the autumn after the crop has been harvested, soil and chemicals left over from farming wash into rivers polluting them. Soil loss from farmland is so serious that Environment Secretary Michael Gove said recently that the UK is 30 to 40 years away from “the eradication of soil fertility”, at which point it is no longer possible to grow food. Although it is possible to prevent soil erosion from happening after maize has been harvested (by sowing grass or other plants which provide soil cover), this has not been widely adopted by farmers. Where soils are very wet, near to rivers for example, undersowing will not prevent agrochemicals from being washed into rivers, polluting them.
Biogas maize also has very little effect on the amount of greenhouse gases released into the atmosphere, which are causing the climate to change. When farmers grow maize they use nitrogen fertilisers, which break down in the soil to release nitrous oxide, which is a very potent greenhouse gas – 300 times as potent as the main greenhouse gas carbon dioxide. Converting pasture into arable land to grow maize also releases the carbon that had previously been stored in the soil. And the tractors, which are taking maize from the fields to the anaerobic digestion plant, are burning through many litres of diesel on each round-trip, releasing carbon dioxide.
There are many better ways to tackle climate change, but biogas maize has been enthusiastically promoted by farmers seeking alternative incomes from their land. The Government has provided generous subsidies to build over 250 anaerobic digester (AD) plants across the country, and give further generous subsidies to grow crops (mostly maize) which are then used as feedstock. Some AD plants only run on food waste, which is more environmentally friendly. Most though consume crops, plus animal manures.
If you are concerned about the impact of growing crops for biogas, you can write to your MP. If you don’t know who your MP is, you can easily find out by using the website They Work For You. Type your postcode into the box to find out who they are. On the MP’s they work for you page, you can contact them by clicking on the “send a message” button.
Send them a simple message saying you are concerned about maize being grown for biogas, using some of the information provided in this article. Ask for subsidies supporting farmers to grow maize for biogas to be withdrawn.
You can also contact your energy provider and ask them if they buy any biogas from producers using maize as a crop; and ask them to stop buying it.