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Fuel for thought

Richard Gueterbock of Clearfleau and Andrew Winship of Aker Associates explain the benefits of using biomethane generated on-site from food and drink process residues as a fuel for HGVs.

As a major consumer of natural resources, the food industry is under increasing pressure to reduce its carbon emissions and its wider impact on the environment. Food and beverage businesses also need to access alternative clean sources of energy not only for their production processes but also for the transport of raw materials and products. Generating bio-energy on-site, including biogas from factory process residues, can offer an attractive solution to both these requirements.

Developing bio-energy solutions, such as bio-methane for commercial transport fuels, offers an opportunity to employ innovative engineering skills to make better use of available resources. The circular economy requires new sources of raw materials, more efficient production and packaging systems and low-carbon fuels for production and delivering products within the retail system.

The food industry is already replacing more traditional, energy-intensive solutions for disposal of its processing residues with on-site bio-energy generation. Developing clean transport fuels can further transform outdated business models that evolved when resource efficiency was of less concern. Production of bio-fuels from residues is already happening and bio-methane is available from existing supply chains, including an increasing number of anaerobic digestion (AD) plants on factory sites.

Developing clean transport fuels can further transform outdated business models that evolved when resource efficiency was of less concern.'

Decentralised on-site bioenergy

Food and drink manufacturers are recognising the commercial benefits of decentralised energy from bio feedstocks. This includes deploying AD to convert energy-rich process residues, such as those from distilleries and dairies, into valuable renewable energy for use in the factory, while minimising disposal costs and cutting fossil fuel consumption by up to 30%. In the past decade, about 30 such AD plants have been built on UK factory sites, reducing emissions and providing an attractive return on investment.

For example, one of Europe’s largest cheese creameries, First Milk’s Aspatria in Cumbria, uses this technology to provide energy to power the factory. The on-site AD plant converts unwanted cheese-making residues into biogas, supplying upgraded biomethane via the gas grid to the site and other local users. The process allows First Milk to save money on its fuel bills, avoid previous costs of disposing of the residues and reduce the site’s carbon emissions. AD is converting co-products from Diageo whisky distilleries in the Scottish Highlands to biogas to heat the stills and is also being used in the dairy, food and biofuel sectors. Decentralised energy potential in these sectors is based on the latent calorific value of energy-rich liquid (and solid) process residues. Ongoing technology improvements (e.g. process control, biogas yield, COD removal efficiency, ability to recycle grey water or plant footprint) have enhanced potential payback. The challenge faced by industry and its regulators is to extend this approach across the food processing sector.

Enabling smaller factory sites to make use of the calorific value in their residues, rather than export their potential energy value, represents progress towards a more circular economy.

Bio-energy alternatives to fossil-fuel based energy are not limited to biomass and bio-digestion but include fuel cells and hydrogen energy. Benefits include improved bio-security, as residues are converted to energy where they arise without having to be stored or transported. Substituting fossil fuels with biogas, biomethane, biodiesel or hydrogen adds value to discarded materials, reducing production costs. The benefits of on-site bio-energy are clear but, particularly with smaller sites, the technology must meet energy needs, be affordable and match the space available.

With on-site digestion, individual facilities are tailored to the specific requirements of the site. Developing a more modular approach to plant design helps to facilitate export opportunities and make plants affordable on smaller industrial sites. As the government continues to curb the incentives that have stimulated investment in renewable heat and power, bio-based fuels are becoming an increasingly attractive alternative to high-emission fuels, such as diesel, for use in heavy goods vehicles (HGVs).

Fill 'er up: truck refuelling with biomethane fuel Courtesy of CNG Services – www.

Biogas as vehicle fuel

The food and drink sector is intimately linked with the wider environment. With the majority of its feedstocks derived from agricultural processes, the industry can do more to limit the environmental impact of its operations. Transport is also a key function for any business. Raw materials need to be brought to the processing site and finished products distributed to the wider market.

To date, utilising biogas on factory sites has mainly involved Combined Heat and Power (CHP) engines, which both generate electricity and provide heat. However, biogas can also be used in the transport sector. A recent study, undertaken by Aker Associates for Clearfleau, investigated smaller scale, onsite production of biomethane and showed that it has a viable future in the food sector as a low carbon alternative to diesel in commercial vehicles and HGVs.

This approach is especially appropriate in the dairy sector, using biomethane generated on site from milk processing residues as a fuel for trucks that collect milk from local farms and deliver cheese, yoghurts and other products to retailers.

To use biogas in existing truck engines, they must be converted to operate on Compressed Biomethane (CBM) or Liquid Biomethane (LBM). However, more truck manufacturers are now supplying new trucks with gas engines. There are five principle technologies for converting raw biogas into biomethane by removing the carbon dioxide and other impurities: Pressure Swing Adsorption (PSA), Water Scrubbing, Amine Scrubbing, Membrane and Cryogenic processes. The biomethane must be compressed or liquefied to produce the fuel. The Clearfleau study included a detailed financial evaluation of both CBM and LBM conversion, showing an attractive return on investment, which will improve as diesel prices rise.

Simple payback at a smaller milk creamery for CBM was estimated at 5.7 years and for LBM at 7.5 years, comparing favourably to using biogas in combined heat and power (CHP) units to generate electricity at 5.6 years. The economic viability of biomethane for industrial transport also depends on a range of site-specific factors, such as the number and type of trucks and how they operate from the site, the quantity and nature of organic residues available, volume of biogas produced and site location.

Currently, the dominant fuel for commercial vehicles is diesel. Concern about air pollution contributing to premature deaths of thousands of people each year has resulted in the emergence of clean air zones in cities to restrict the movement of the most polluting vehicles. It may even result in a ban on the use of diesel in major cities, as reported recently in Paris. This will have a major impact on the operations and profitability of food and drink manufacturers, which will need to find alternatives to diesel. While there has been huge growth recently in the uptake of electric vehicles, this is not a viable solution for commercial transport, as the technology is not suitable for larger, heavier trucks.

Converting process residues from food and drink manufacture into biomethane is therefore an obvious solution. Vehicles are continuously entering and leaving the site making it an ideal location to set up the refuelling infrastructure, with the feedstock (residues) to produce the fuel readily available. By producing renewable fuel on-site, a business can help insulate itself from rising prices and make fuel cost budgeting more predictable.

Elsewhere in Europe, use of biomethane as a transport fuel is not new. Other European countries have developed a market for gas-powered vehicles, with production and refuelling technology having been in use for many years for commercial transport fleets using gas to power HGVs. Companies like Arla and Waitrose are using compressed or liquefied natural gas (CNG and LNG) and biogas alternatives, with trials showing the potential to deliver significant greenhouse gas savings.

Gas-powered HGVs have been demonstrated to produce lower emissions of NOx, particulates and CO2 and are claimed to be quieter. Biomethane provides an even lower carbon alternative to the CNG and LNG powered trucks already being used in some commercial vehicle fleets.

In the UK, incentives are in place to encourage wider adoption of biomethane as a transport fuel through the Renewable Transport Fuel Obligation (RTFO) and by development programmes like the recently announced Future Fuels for Flight and Freight Competition. Converting process residues into renewable transport fuels is economically viable, giving the food and drink industry another option in its progress towards emissions reduction, improved sustainability and embracing the circular economy. Government could do more to encourage the wider use of gas engine technology.

While there has been huge growth recently in the uptake of electric vehicles, this is not a viable solution for commercial transport, as the technology is not suitable for larger, heavier trucks.'

Promoting a low carbon economy

After the 2015 Paris COP21 ClimateChange Convention, a group of leading food and drink sector multi-nationals made commitments to change their practices, signing a statement of intent: ‘We want the facilities where we make our products to be powered by renewable energy, with nothing going to waste, as corporate leaders, we have been working hard toward these ends, but we can and must do more.

With global food companies setting ambitious targets for reducing greenhouse gas emissions and developing a more circular economy, British firms need a supportive policy framework.Companies that have installed onsite bioenergy plants are benefiting from incentive revenue and cost savings, while boosting their CSR profile - compelling reasons for the Government to promote the decentralised generation of bioenergy as part of its industrial strategy.

The bio-economy (including forestry and the agri-food sector) contributes about £36 billion in gross value added (GVA) to the UK economy, of which over 80% is from food and farming. In 2012, industrial biotechnology and bio-energy contributed 3% to the sector’s GVA; with the right support this can grow substantially.

The technology for producing low carbon bio-fuels from process residues is already well established and biomethane offers an existing supply chain with an increasing number of AD plants on factory sites.

The Government’s Policy Green Paper ‘Building our Industrial Strategy’ highlighs the value of cleaner technologies but does not indicate how bio-engineering and renewables will be promoted when existing incentive regimes expire. Development of the biomethane sector for HGV fuel needs on-going support through the RTFO and other taxation measures; biomethane should be included among the low carbon development fuels.

In developing its ‘Clean Growth Strategy’ the Government needs to provide a period of policy stability for industrial bio-energy to fulfil its potential. Smaller businesses need support if they are to match investment in the circular economy by larger companies. With British bio-energy companies developing smaller on-site solutions, wider adoption of industrial bio-energy can stimulate economic growth, boost engineering jobs, help the UK meet sustainability goals and encourage innovation.



A process that can occur in air or free oxygen.


A process that occurs in the absence of air or free oxygen.


Gas produced from the biological degradation of bio-residues in

the absence of air or free oxygen comprised mainly of methane and carbon dioxide.


Enriched biogas achieved by purification/ removal of carbon dioxide.


Biodegradable materials from manufacturing processes (also co-products).


Renewable (non-fossil) energy derived from organic biomass, inc. bio-residues.

Chemical Oxygen Demand

Measurement of degradable organic compounds in effluent. COD test results are used to indicate level of decomposing pollutants that absorb oxygen from water.

Richard Gueterbock, Marketing Director for Clearfleau, has been with the company since it was founded. He has a background in the agri-food sector and is a former trustee of the Royal Agricultural Society of England. Clearfleau is a provider of on-site bioenergy plants for food and beverage processing factories, with operational plants and others in build in the food, dairy, drinks and biofuel sectors.

Andrew Winship, Director Aker Associates, has more than 25 years of experience gained from working in the oil, chemicals and clean energy sectors. His areas of expertise cover combustion processes, biogas/biomethane, hydrogen and CO2

Aker Associates is an independent consultancy and advisory business to the clean energy sector specialising in business development, technology commercialisation, innovation management and project development.

To find out more about using Biomethane as Transport Fuel or to download a summary of Clearfleau’s report, please visit


1. Building Our Industrial Strategy – Government Green Paper January 2017

2. Glyn Chambers, Alexandra Dreisin and Mark Pragnell, “The British Bio-economy - an assessment of the impact of the bioeconomy on the United Kingdom economy” Capital Economics Ltd, 11 June 2015,

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