Anaerobic digestion in farming can deliver the benefits of a rural economy, food security and environmental protection.
AD supports the rural economy by diversifying farm incomes. AD can transform farm material, including slurries, crops, chicken litter, vegetable off-cuts, outgrade crops or animal by-products into a new income stream for the farm. For a farm integrating on-farm AD plants into its business, around third of the farm income may come from exporting energy. This reduces the volatility of the farm’s income, helping farmers stay profitable in challenging market conditions whilst also supporting food security and stabilising food prices. Some AD companies are also now selling their crop-derived digestate in the retail market, diversifying their income streams even further.
As well as additional income streams, AD can reduce operational costs and improve the productivity of farms.
- By using nutrient-rich digestate produced from farm material, farm fertiliser costs can be reduced and yields increased
- The on-site generation of renewable energy can displace the need to purchase expensive retail-price energy
- A rotation of AD and food crops can provide a natural method of managing weeds and crop diseases – for example, environmental consultant ADAS has reported that 58% of the UK wheat crop currently suffers from blackgrass. Crop rotations can help tackle this, therefore reducing the cost of expensive chemical treatments.
- The application of digestate helps maintain pH and soil fertility and helps build organic matter, therefore improving food and AD crop yields
- Marginal land can be brought back into productivity, leading to higher income per unit of land
- New opportunities arise to better protect soil and increase financial returns through the off-season harvest of energy crops, overwintered stubbles and cover crops
- Wildlife is attracted by the increased variety of crops and reduced chemical inputs AD protects the environment not only through the digestate, manure management, crop-rotation and wildlife benefits listed above but also through the emissions reductions
Towards a common goal
The National Farmers’ Union (NFU) has committed to achieving Net Zero across agriculture by 2040. “AD has an integral part to play in that. With AD we can put something in and get value out – nutrients and methane,” NFU Vice President Stuart Roberts, told the ADBA National Conference in 2019.
“We are part of the climate change solution. We need the new government to be really ambitious and gives us the policies to put a rocket under the industry and drive us forward.”
He proposed a roll out of “more than 100 plants plus a year”.
“The NFU backs and supports this industry that positively adds value to something we call waste but it isn’t waste. We can’t deliver net zero without partners and without you guys we can’t deliver sustainable agriculture.
Did you know?
- More than five tonnes of carbon dioxide are emitted for each tonne of nitrogen fertiliser produced. So when digestate is used in place of factory-produced fertiliser, the factory emissions are avoided.
- Methane produced by rotting manure and slurry is one of the hardest sources of UK and global emissions to avoid. But AD can ensure this major source of agricultural emissions is avoided.