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Crop residue and anaerobic digestion position clarified by the environment agency


The Environment Agency regulates all facilities that handle waste, and requires such facilities to have in place an environmental permit. Until recently, the use of crop residues in the Anaerobic Digestion (AD) process required producers to hold an environmental permit due to the crop residues (such as leaves and roots, or misshapen or bruised produce) being classified as waste. This was a disincentive to on-site and on-farm facilities, as if a farmer wanted to add even a small amount of such products to their AD facility, it would mean having to apply for a permit and implement strict waste handling controls. This meant that farmers ended up using purpose-grown crops in their AD facilities due to their classification as non-waste. This hardly accorded with the aim of reducing food waste and reducing carbon emissions.


The Environment Agency published a Briefing Note in September, which clarified the regulatory position in relation to the use of crop residues in the AD process.

Crop residues will be classed as by-products (and not waste) providing the following circumstances apply:

  • It is a production residue produced as an integral part of the commercial production of agricultural crops, for example misshapen and undersized fruit or leaves and roots which are removed as part of processing. However, surplus and reject fruit or vegetables from supermarkets and leftovers and scraps from restaurants are still classed as waste
  • It is not mixed with or does not contain any waste
  • It is suitable for use as feedstock and it is certain to be used in the AD process, with no additional processing apart from that expected for energy crops (maceration would be ok but depackaging or pasteurisation would not)
  • Its use will not have an adverse environmental or human health impact, this includes the storage and processing of crop residues, the AD process itself, as well as the storage and use of the biogas and digestate produced.

If the circumstances are met the crop residues will not be classed as waste and therefore, producers will not require an environmental permit where they only take the following feedstocks:

  • purpose grown crops
  • crop residues that meet the above criteria
  • a mixture of purpose grown crops and crop residues which meet the above criteria.

Impact for Biogas Producers

The clarification by the Environment Agency should provide a boost to the on-site and on-farm AD industry, as a significant regulatory barrier has been removed. The move should encourage growth in the industry and bring online producers who have been held back by the previous requirement for an environmental permit.

However, it would appear that the impact on existing producers may be minimal, as many plants use a combination of waste feedstock alongside crop plus crop residue feedstock. Therefore, existing producers will need to balance the gains to be had from continuing to accept a wider range of feedstock against the benefits of a reduced source of feedstock that does not require an environmental permit.