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Time to maximise the use of biomethane as transport fuel

Time to maximise the use of biomethane as transport fuel

by Dr Nick Primmer, Lead Policy Analyst, Anaerobic Digestion and Bioresources Association

The Department of Transport’s Decarbonisation Plan is a missed opportunity to drive the mass adoption of biomethane – the only fuel technology available today to achieve Net Zero.

This year, the world’s scientists issued a clear message to humanity: we have less than 10 years to avert climate catastrophe. Action now is the call, yet action tomorrow remains the political response.

No more so than in the transport sector, which contributes 27% of the UK’s greenhouse gas (GHG) emissions. It is the largest contributor, yet the slowest to decarbonise – only achieving 5% emission reductions since 1990.

The UK’s Net Zero strategy looks at electricity and hydrogen to address transport emissions, despite critical practical and technological barriers that means it will be decades before the impact can be felt. Meanwhile, ready-to-use solutions such as biomethane, which currently deliver the greatest carbon savings, continue to be overlooked.

The Transport Decarbonisation Plan published in July by the Department for Transport (DfT) overly focuses on tailpipe emissions, mandating all vehicles to be zero tailpipe emissions by 2040. Unlike well-to-wheel (WTW), which considers emissions incurred from the fuel’s production stage all the way to engine combustion, the plan refers to Tank-to-Wheel (TTW) emissions, which only apply to vehicle use. This strategy unhelpfully favours the use of fossil-generated electricity, shifting the emissions to the wider energy sector. An electric vehicle (EV) may well be carbon free, but unless it is charged with renewable electricity, it leads to carbon being spewed out upstream instead.

Additionally, while electricity is a viable solution for cars and vans, it does not work for long haul, heavy vehicles such as HGVs, responsible for 17% of total UK transport emissions. Range and refuelling times remain a major hurdle; for HGVs, there is only one mass adoptable fuel and vehicle technology that can deliver decarbonisation immediately, and that is biomethane.

Yet, biomethane is a clear loser in the DfT’s decision to convert all road vehicles to zero tailpipe emission ones by 2040. Biomethane HGVs do emit CO2 from the tailpipe. However, that fuel is carbon neutral. Being produced from the anaerobic digestion (AD) treatment of organic feedstocks – i.e. plants which have absorbed CO2 via photosynthesis, biomethane emits carbon which was initially found in the atmosphere. It is this biogenic CO2 which is released when biomethane is combusted inside an engine – creating a sustainable carbon cycle, and achieving carbon neutrality.

The biomethane produced from organic wastes can also be carbon negative – i.e. generating over 100% emission savings compared to diesel, as AD captures the methane that would be emitted by those wastes if they were left to rot in landfill.

A biomethane-fuelled lorry will emit over 80% less COthan a diesel Euro VI vehicle. This represents a saving of 150 tonnes of CO2 per vehicle annually. Adopting biomethane for the HGV, bus and coach sector can deliver an immediate 20% cut in GHG emissions. Other benefits include: >70% less NOX, and 99% less particulate matter.

Biomethane not only makes sense environmentally but also economically. Gas’ fuel duty is up to 40% cheaper than diesel and, despite higher initial capital investment and maintenance costs, gas vehicles travelling 160,000 km/year can deliver a ROI within 2 years.

That is why many companies are now adopting biomethane for their fleets – Hermes, John Lewis, ASDA and Royal Mail among them. Cities such as Nottingham and Bristol have adopted biomethane buses for their health and environmental benefits, while Liverpool is now using biomethane-fuelled refuse collection vehicles.

Current production of biomethane could fuel 8% of the HGV fleet. At its full potential, biomethane could fuel 97% of the fleet. There are over 520,000 HGVs in the fleet; if all turned to biomethane, 24m tonnes of carbon emissions could be avoided. This could – and must – be achieved by 2030.

The government needs to urgently rethink its approach to decarbonising the transport sector. Humanity cannot wait until tomorrow…


Decarbonising transport will be a topic at the forthcoming ADBA National Conference on 14th December 2021. Find out more and register here.


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