Slowly but surely land across the UK is being gobbled up to grow maize as an energy crop. Bioenergy can be a good thing if food and organic waste is used. But taking fertile land out of food production, when the UK is only 65% self-sufficient in food, is seen, by some, as indefensible; maize grown solely for biogas also raises environmental concerns.
Although wheat and sugar beet are also planted as bioenergy crops, it is the area allotted to maize crops for energy that has mushroomed in recent years. The latest government figures show that 88,000 hectares of maize are now planted each year just to feed anaerobic digestors – the industrial plants that create the energy. This is a huge landmass: in just six years, this area has grown by 35%, and is now comparable to an area the size of Edinburgh, Bristol and Leeds – newly planted with maize solely for biofuel.
These crops now feed 750 biogas plants across the country, according to the Anaerobic Digestion and Bioresources Association. Just under a third of all feedstocks used in all of these digestors are crops that are grown for the sole purpose of producing bioenergy. The industry has big plans for growth and wants to supply up to 50% of the country’s gas needs in the years ahead.
Biogas may be greener but only if it’s from sustainable and environmentally-friendly feedstocks. Purpose-grown maize for bioenergy uses fossil fuel-based fertilisers, causes soil compaction, leaves the earth bare for long periods and leads to phosphate runoff into rivers. All these factors contribute to a lot of pollution, states The Wildlife Trusts in a recent post. This comes at a time when soil health and water quality are in the spotlight.
“The area planted has grown really steeply over the last few years and that’s concerning. The fact that the UK public is also subsidising biogas produced from maize and other crops is also worrying. Growing food crops for biomethane has to stop. This is an insane way of generating energy,” explains Almuth Ernsting, from advocacy group, Biofuelwatch.
Funded by the UK taxpayer
The agricultural sector is supported in this biomethane boom through various government subsidies including the Green Gas Support Scheme (GGSS). This provides payments for generating biogas. These subsidies have now been extended to 2030. The subsidy for the GGSS alone costs over £96 million a year and is projected to rise.
The UK taxpayer is unwittingly fuelling the planting of more maize for biofuels – an unintended consequence of going green, yet subsidies can be perverse.
If maize for bioenergy is planted on peat soils, say in the east of England, then this can emit three times more carbon than using natural gas, according to research by the Centre for Ecology and Hydrology.
“The lifecycle emissions of growing maize are not considered in many equations, including the impact of using nitrogen fertilisers. Then there are methane leaks and slippages – so called fugitive emissions. There should certainly be no subsidies whatsoever for biogas made from the planting of these crops or grasses,” states Ernsting.
Comparing bioenergy crops to viable and affordable alternatives to energy production can be helpful. Solar farms generate 12–18 times more energy per hectare than maize or grass grown for anaerobic digestors. Wind, solar and other renewables also produce far lower emissions, according to a report by Foodrise. The price of renewable kit has also never been cheaper. The much cited Climate Change Committee, which advises the UK government on these very matters, expressly states that we need to phase out the use of maize for biogas by 2035 and shift to growing and subsiding perennial energy crops instead, such as Silphium for instance.
This appears to be at odds with the current direction of travel. The hundreds of digestors across the UK now need continuous feeding. There are also new gas-to-grid plants coming online. These pump biomethane directly into the nation’s gas supply. High energy prices with the war in the Middle East are also likely to fuel the biomethane market going forwards.
The worrying appeal of maize
The attractiveness of maize for farmers is that it has both a high yield per area and a high yield of biomethane per tonne. Hence why the area planted has mushroomed and is favoured by growers. It’s why almost one-third of the total maize area planted in the UK now goes to anaerobic digestors.
However, maize is also a hungry crop demanding substantial inputs to achieve high yields, in terms of water and nitrogen fertilisers. Then there is the maize-based digestate, which is the waste material left after the digestion process, which is also high in ammonia and spread on fields by farmers.
“Biogas may have a role, but it poses serious problems when crops are grown to feed anaerobic digestion plants,” explains Maddy Potter Wood, Policy Officer, Farming and Land Use at the Soil Association. She adds: “Our Stop Killing our Rivers campaign highlights the impact of intensive poultry units on river catchments such as the River Wye. We found that the growth in anaerobic digestion plants processing chicken manure went hand-in-hand with increased maize production. A more sustainable and nature-friendly solution could be to shift away from the intensive production of crops for these units and towards the use of waste products where these can’t be used for other purposes.”
For those concerned, it is now going to be harder to track how much land will be planted with bioenergy crops going forwards. As if February last year, the UK government, by their own admission, are no longer publishing figures. It means that there will be no understanding of how much land will be gobbled up by maize for biofuels in the near future. “This is bad news and worth challenging,” states Vicki Hird, Strategic Lead for Agriculture at The Wildlife Trusts.
What could make things worse is that the UK government has just finished a consultation, considering how crops could be used for “sustainable” aviation fuel. This is despite opposition from a number of transport organisations that have serious sustainability concerns about planting more food crops to produce jet fuel.
“We hope that the new Land Use Framework will help to ensure that farmland is prioritised for nature-friendly food production, which should include a reduction in intensive livestock production and moving away from growing crops for biogas,” concludes Potter Wood.
All the key indicators, projections and assumptions look set for the continued growth in food crops for energy use, which includes the planting of maize. Only legislation can really curtail this but will the government take on board the Climate Change Commission’s advice?
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