A survey of the UK Anaerobic Digestion industry in 2013 (ASORI)

11th December 2014

A report on the structure of the UK Anaerobic Digestion sector and the markets for its outputs.

Key points
Number of operational sites increased by 34% compared to 2012
Operating capacity up by 55%
51% more organic material processed
Employment up by 36%

Cumulative no. of facilities

UK AD 2013 supply chain flow

Click image to view larger version.

The purpose of this study was to quantify the processing of organic material via anaerobic digestion (AD) in the UK using a survey of AD operators. This report summarises the methodology employed and the results obtained from the survey.


A survey of the organics processing industry has been undertaken since the mid-1990s, originally by The Composting Association (with funding from the Environment Agency and WRAP support in later years) and more recently by WRAP with the support of the Anaerobic Digestion and Biogas Association (ADBA), the Renewable Energy Association (REA) and the Environmental Services Association (ESA). As last year’s survey indicated little year-on-year change in the UK composting sector and the AD sector has been developing rapidly, this year resources were focussed on surveying AD only.


A telephone survey was carried out between February and April of 2014, collecting data on the state of the sector in the calendar year 2013. Attempts were made to contact all of the AD plants listed on the AD Information Portal map, with the exception of water (sewage) treatment plants and mechanical biological treatment (MBT) plants which process residual waste but have an AD plant to process the organic fraction extracted. This survey classifies AD plants into four categories, as follows:

  • Commercial – sites which accept waste from off-site, on a commercial basis (i.e. for a gate fee). Such sites may be based on a farm.
  • Industrial – sites which process their own wastes, typically on a large scale, such as food and drink manufacturers.
  • On-farm – sites which are both located on a farm and process only material generated on-farm (including energy crops).
  • Demonstration – demonstration/R&D sites. AD sites that process feedstock for demonstration or feasibility purposes. Such sites may contract in waste but not on a large scale.

The response rate was 75%: 88 sites answered at least some of the survey questions,  out of an operational population (during 2013) of 117 sites. This compares to a response rate of 70% (61 out of 87 operational sites) in the survey of 2012.

Key Findings

  • There has been a 34% increase in the total number of operational AD plants between 2012 and 2013, up from 87 to 117 plants, and an increase of 51% in the tonnage of organic material processed, from 1.69 million tonnes to 2.55 million tonnes, excluding those AD plants typically associated with the drinks industry which use AD to process liquid effluent and discharge the treated effluent to sewer.
  • Total UK employment in the AD sector is estimated at 482 full-time equivalents in 2013 compared to 354 in 2012 i.e. a 36% increase.
  • The largest increase in numbers of operating plants has been in the commercial AD sector (up from 31 to 37 plants) and on-farm plants (up from 32 to 50). There has also been an increase in the number of industrial sites which discharge treated effluent to sewer, from 11 to 16.
  • The operating capacity of the AD sector, excluding the industrial sites which discharge treated effluent to sewer, has increased by 55% since 2012, from 2.07 million tonnes to 3.20 million tonnes. Similar rates of increase (i.e. around 50%) have been seen in each of the three main segments: commercial, industrial and on-farm.
  • There have been increases in all the types of feedstock processed: separated solid food, liquids, manures and crops but food and drink waste continues to be the largest proportion of the material processed, with separated (solid) food at 38% of the reported  tonnages and liquids at 30%. Correspondingly, the largest source of feedstock is food manufacturers and processors (66% of the waste organic material processed – i.e. excluding energy crops and manures). This year’s survey saw an increase in the reported tonnages processed from this source from 330,000 tonnes in 2012 to 820,000 tonnes in 2013. In comparison, the reported volume of material sourced from Local Authority collections increased from 170,000 tonnes to 230,000 tonnes. It should be noted that because these are reported  tonnages, the changes between 2012 and 2013 are a combination of real growth and improved reporting (more sites providing answers).
  • Over a million tonnes of digestate were reported to have been applied to agricultural land in 2013, providing benefits in terms of readily available nutrients and potentially lower use of inorganic fertilisers. This represents 98% of the digestate for which a use was reported in the survey and highlights the importance of a ‘land bank’ to which to spread digestate, particularly for commercial AD operators.
  • There still appear to be very few AD operators who are realising a market value for applying digestate, with those who are prepared to disclose financial arrangements disclosing prices for agricultural application ranging from a cost to their business of £13 per tonne to a revenue of £3 tonne, with an average of -£3.73 per tonne (i.e. a cost to the business). 
  • The increasing number of food and drink manufacturers using AD to process their waste  also means that value (mainly energy) is increasingly being created out of waste and untreated waste is less likely to be disposed of to sewer or to land.
  • Our survey shows that the majority of plants in 2013 were using CHP with very little heat use - much the same as in 2012. Although this survey asks for electricity generation figures, the more authoritative figure for electricity generation by AD is published by DECC
  • The survey also asked about attitudes to the PAS110 certification system and responses showed a continuing intention to apply for and maintain certification, mainly among commercial operators.