Valorising Agri-Waste

Posted in: feedstocks

Agriculture produces an unsustainable amount of waste, so how does the bioeconomy let us derive value from it?

For every kilogram of “usable” crop produced in agriculture, between 1 and 2.5 kilograms of residue is also produced. Of course, some of this residue must remain in the field or be used elsewhere on the farm in order to maintain a healthy ecosystem, but that which isn’t used thus is an unavoidable waste.

Minimising waste is one of the central tenets of sustainability: the waste hierarchy dictates that if waste cannot be prevented, then the next best option is to in some way reuse or recycle said waste. Unavoidable food supply chain wastes (UFSCW), including crop residues, by-products of food processing such as apple pomace or olive mill waste, and livestock manures, represent a source of organic matter that can be used as a feedstock for biofuel, bioenergy, or biobased material and chemical production. The key to utilising UFSCW in this manner is to ensure that there is value in the eventual product, to ensure market uptake. This process is known as valorising, and has been the focus of several EU projects in which NNFCC has worked, such as Agrocycle and DAFIA.

For some end-markets for UFSCW, such as biogas, years of government support in the form of tariffs have seen successful markets be established, but in an ideal world technologies such as anaerobic digestion should be able to compete with less-sustainable alternatives without outside support, and so more work is needed.


The chief aspect that waste biomass valorising is up against is the low cost and established value chains of fossil fuels. This adds an additional market pressure to any biobased alternative, as it must compete with fossil fuels’ low end-market price while holding higher processing costs due to the fact that biomass is inherently more chemically complex than fossil fuels. These, coupled with technical barriers presented by many biomass processing technologies remaining at the pilot or demonstration plant scale, further skew the stakes against biomass. This problem is compounded for novel technologies whereby economies of scale see ideas early in development struggle to find a foothold due to lack of engagement from potential stakeholders. Agri-wastes have the additional problem of increased heterogeneity compared to other biobased feedstocks such as dedicated biomass crops and wood pellets. Local agricultural activity will often determine availability of certain kinds of feedstocks, meaning biobased processes utilising agri-wastes have to be either flexible or broad. This couples with the inherent seasonality of agri-waste production, which can be accounted for, but is nonetheless an additional consideration that fossil value chains do not have.

It may all seem like an insurmountable task, but the need for sustainable development is not going away, and so business models surrounding successful use of agricultural wastes must be developed. The bioeconomy can point to recent success stories as inspiration: the establishment of the anaerobic digestion sector in the UK and beyond shows that even small-scale stakeholders are willing to adopt novel sustainable technologies with the right support, and that this can have benefits across multiple sectors: from energy to transport.

A successful novel business model has to consider how the organisation in question is able to deliver value from the available agri-waste feedstock, and that feedstock must be available – it does no good for a novel biobased process to direct feedstock away from an existing one – as well as unavoidable. Avoidable wastes should be dealt with through prevention, according to the waste hierarchy, whereas crop wastes are unavoidable (until such time that all parts of each food crop form part of human diet). It is here that projects such as Agrocycle and DAFIA come to the fore, by bringing together stakeholders from across the bioeconomy to establish what opportunities are available, and to collaborate on how best to exploit them. As part of the Agrocycle project, NNFCC produced several factsheets detailing the available value chains for multiple agri-waste feedstocks. These factsheets are available to download here.

With over a billion tonnes of UFSCW being produced in Europe every year, it is not a question of the potential scope for agri-waste valorisation, but one of how well the opportunities available can be exploited, to “close the loop” and bring agriculture closer to a sustainable circular economy.

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This article was written by Bob Horton, Research Analyst at NNFCC.

View the Agrocycle Factsheets here: