Runaway maize? AD sector fends off criticism over damage to land

The anaerobic digestion (AD) industry has hit back at criticism from the Soil Association which claims that soil destruction caused by biofuel production is threatening the UK's food security.

A report by the Soil Assocation – Runaway Maize: subsidised soil destruction – argues that maize grown for AD plants is increasing environmental degradation.

Maize crops leave soil exposed, causing surface water runoff, which the Association says is adding to water pollution, flooding and soil degredation.

The AD industry uses plant materials or waste to produce biogas and is currently subsidised under the Feed-In-Tariff and Renewable Heat Incentive policies, with UK farmers also receiving the Basic Farm Payment for growing maize under the Common Agricultural Policy.

National scandal

The Soil Association says it is a ‘scandal’ that UK taxpayers are subsidising AD plants which use maize and called for an end to all subsidies for digesters using the crop.

Peter Melchett, policy director at the Soil Association, said: “Maize crops damage soils and fresh water. Many farmers are being paid to cause significant harm to the vital resources we rely on for survival – this is a national scandal.

“The UK Government must take action by ending subsidies for maize grown for energy and by introducing strict measures for management of maize crops. It is possible to grow maize to better practice standards that reduce the risks to soils and the environment – some farmers are following good practice, but not enough of them.”

According to the Soil Association, the rapid expansion of maize for AD is a particular threat to farmers due to higher rents and a risk to the means to produce food for the UK. The expansion has led to a land grab, increasing farming rents, the Association says.

The report estimates that maize-using AD plants are costing British energy consumers up to £50m per year in subsidies. However, the Soil Association said biogas production from waste materials should continue to recieve financial support.

Sustainable role

The Anaerobic Digestion & Bioresources Association (ADBA) has questioned the Soil Association’s conclusions, with the industry body claiming AD crops can in fact play a crucial role in sustainable agriculture.

ADBA chief executive Charlotte Morton told edie that the industry was committed to its responsibility to the local environment. “We need bioenergy to meet our climate change targets as well as to keep the lights on and biogas is one of the most efficient forms available,” said Morton.

“The AD industry has the potential to reduce climate emissions, including from farming, by as much as 4% and generate around 30% of the UK’s domestic gas demand.”

Morton said the AD industry currently grows just 30,000 hectares of maize for AD, using just 0.6% of England’s arable land. The AD industry is in fact helping to restore soils and reduce the need for carbon-intensive fertiliser, with Morton adding that ADBA’s members – operating 34 plants – have already signed up to a best-practice policy for crops production in AD.

“By recycling the nutrients and organic matter in the digestate biofertiliser back to land, the AD industry is helping to restore our soils and reduce the need for carbon-intensive commercial fertilisers,” she added.

Circular economy

On the Soil Association’s criticism of subsidies for AD, Morton responded: “The Soil Association’s proposals on incentives and the Common Agricultural Policy don’t make sense. The Basic Payment Scheme (BPS) doesn’t allow for differentiation on the basis of how a crop is used, and farmers may not have control over this anyway.

“Amending the scheme would therefore be costly and virtually impossible – and models for renewable incentives use a crop price which assumes the BPS is in place so there is no double-counting.”

Morton previously told edie that AD was one of the few circular economy technologies already delivering commercially. 

Interactive map: Active AD plants in the UK

Matt Field

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