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Anaerobic digestion (AD) is clearly a topic that needs re-visiting. The government’s Waste and Resource Strategy estimates that around 10 million tonnes of food and drink waste (post-farm gate) is produced annually, with households – according to the Waste and Resources Action Programme group (WRAP) – being responsible for around 6.5 million tonnes of this. The strategy commits to ensuring that through legislation, and subject to consultation, every householder and ‘appropriate’ businesses will have a weekly separate food waste collection by 2023. The strategy also recognises that AD technology currently represents the best environmental outcome for food waste that cannot be prevented.

Although AD is not a new concept, the last decade has seen a rise in the number of AD plants coming online. AD plants are typically well suited to rural environments, particularly agricultural holdings, and vary in scale and choice of feedstock, from larger scale facilities accepting municipal waste and sewage sludge to smaller facilities handling local farm derived waste.

The AD sector has however struggled in recent years. This is partly due to decreased subsidies from the renewable heat incentive (RHI) scheme which was reportedly not compatible with construction and operational costs, as well as issues relating to the reliability of feedstock. This resulted in an oversupply in AD capacity due to the over-estimation of food waste collected as a separate fraction, with significant amounts of food waste remaining within residual waste streams and disposed of through landfill or ERF treatment routes. This in turn led to low gate fees – good for producers, but not so much for operators – with the 2015/16 WRAP Gate Fees Report reporting a median average of £40 per tonne, reducing to £29 per tonne in the following year. Limited feedstock also encouraged poor maintenance of capital infrastructure with operators turning to lesser preferred feedstock materials which may be contrary to the input specification in order to feed the process, as well as a rise in mixed feedstock plants to ensure stability of supply. The most recent WRAP Gate Fees Report, published in September 2019, reported gate fees for AD plants currently averaging at £27 per tonne. The lack of significant change in gate fees since 2016 is largely reflective of the absent changes in feedstock availability.

Southern England’s ability to meet change regarding anaerobic digestion

This article aims to provide an overview of the southern England’s ability to meet the change in the market over the coming years. The southern England region – being the study area for this article – comprises the Counties of Hampshire and West Sussex where only one out of twenty local authorities currently provide a dedicated separate food waste collection service for households. Other authorities across the region, namely Portsmouth and Mid Sussex, have either recently undergone separate household food collection trials or are due to carry them out shortly.

Neighbouring Surrey is a different picture, with all local authorities providing a separate household food waste collection service generating around 40,000 tonnes of food waste arisings. This has successfully diverted just over 15% of food waste from within the residual waste stream.

AD Plants within southern England

Within the southern England region, the respective waste planning authorities report a total of 5 AD plants permitted through planning consents across both Counties. West Sussex has three of these. However, one of these plants is currently inactive following planning enforcement action and another is subject to feedstock restrictions to accept material derived from the farm curtilage only. Within Hampshire, there are two plants, with one of these being subject to a condition limiting the amount of off-farm derived waste accepted by the plant.

Household food waste

Drawing on the outcome of Surrey’s successful roll out of dedicated household food waste collection services as a proxy for residual/food waste composition, there is a potential to unlock and make available around a minimum of 85,000 tonnes of food waste across the southern south-east region by 2023. However, this figure of course only accounts for household derived food waste and not commercial sources.

Commercial food waste

With regards to commercial sources, WRAP estimates the restaurant sector alone contributes approximately 200,000 tonnes of food waste per annum. In January this year, the Government announced £1.15 million funding to tackle food waste in households and supply chains. Businesses and not-for-profit organisations in England will benefit from this funding to assist in creating new ways to tackle food waste by changing people’s behaviour or transforming it into other materials.

Across the southern England region approximately 15,000 tonnes of food waste were collected as separate fractions from commercial sources, with no visible upward trend in this amount over the last 3 years. Approximately 40% of this arising is treated indigenously, with the residual amount exported to counties which include Oxfordshire, Wiltshire, Surrey and Buckinghamshire. Recent key recipients of Hampshire and West Sussex food waste arisings have been Buckinghamshire’s Westcott Biogas Generation Plant, sold by Renewi to Olleco in 2018, and Wiltshire’s Old Codford Dairy, operated by Enrich4 Ltd which processes around 80,000 tonnes per annum, – both of which are AD facilities.

AD demand and capacity gap

A potential signal for AD demand within the southern England region is an approach consistent with the statement made by the Environment Agency Chair at the Resourcing the Future Conference in 2019, in that the UK must manage its waste and not pass it on to others and, that the UK must have the right infrastructure in the right places to ensure businesses can do the right thing.

The additional need for AD infrastructure is echoed by the Anaerobic Digestion and Bioresources Association (ADBA) who estimate that around 80 new AD plants would be required in the UK to cope with additional food waste becoming unlocked from residual streams.

Given the current available, unutilised off-farm AD capacity level within the region of around 45,000 tonnes per annum and assuming the Government had achieved, or was close to achieving its aspiration, there would inevitably be a deficit capacity gap in 2023 created by separate household food waste collection and commercial food waste segregation. There would therefore be a demonstrable need to ensure the appropriate level of capacity is provided to ensure the food waste stream is treated close to where it arises through the ‘best environmental outcome’.

The COVID-19 impact

The COVID-19 pandemic has recently led to concerns expressed by the Environment Agency over AD capacity and the sectors ability to absorb the sudden surplus in the amount of organic waste available. This surplus is largely due to the closure, or partial closure, of food and drink producers namely fisheries, farms and breweries.

The Association for Renewable Energy and Clean Technology (REA) and the Anaerobic Digestion and Bioresources Association (ADBA) are to launch a joint survey to identify spare capacity across the UK’s AD sector for this additional feedstock generated by the COVID-10 lockdown to be treated.

The survey aims to inform waste generating businesses of where spare AD capacity is available. This will aid the continued diversion of organic wastes from less preferable routes such as landfill and incineration. Not only does this reflect the Governments position as AD being the best environmental outcome but also demonstrates AD as being a largely resilient sector of the waste industry in times of adversity.


The Planning team at Paris Smith LLP comprise both Chartered Town Planners and Chartered Waste and Resource Managers equipped with both the technical knowledge and expertise to assist the waste management and resource sector in obtaining the necessary planning consents required to meet changing demand and market conditions. The team is further backed up by an experienced team of solicitors providing specialist legal advice and services to the agricultural and rural property sector.

We can help waste operators in responding to this need, by way of ensuring the necessary planning consents are obtained to fill the void so please contact a member of the Planning team. Our Planning law and planning consultancy page has more information on the services we can provide.