The report, which was commissioned by the Department of Transport and the Department of Energy and Climate Change (DECC, now BEIS), finds that biofuels do have a role to play in meeting the UK’s climate commitments, and that on balance biofuels derived from wastes and by-products represent a more sustainable option.

The Royal Academy of Engineering report suggests that, though they present the best option available, action is needed to manage the risks from second generation biofuels, improve traceability and avoid fraudulent practice. However, this is still better than crop-based fuels, which Academy researchers show can produce higher emissions than fossil fuels. They recommend capping the amount of crop based biofuels in the UK’s energy mix.  

Biofuels have been enthusiastically adopted in some countries, notably Brazil, where first generation fuels derived from maize and other crops are very common. However, their expansion in Europe has been capped by environment campaigners who are concerned at the potential for land use change associated with the development of fuels from crops; there is evidence that producing biofuels leads to more ‘natural’ or semi-natural land elsewhere being converted to agriculture to produce food or feed. The increase in deforestation, drainage of peatlands, loss of biodiversity, and use of water and agricultural chemicals this conversion brings can negate the benefits of even more benign crop-based biofuels.

Although they were initially embraced by governments as a renewable, low-carbon alternative to fossil fuels, and production was subsidised in many areas, including the EU, first generation biofuels have been shown to be just as polluting as their fossil equivalents, even more so when emissions associated with their production and impact on land use are factored in. This was a hard won argument in the EU, where amendments to laws governing biofuel production were eventually passed in 2015. Even so, campaigners at the time said the EU had not gone far enough in its eventual row back.

In the Academy report, one of the authors even suggests that, in some cases, governments would have been better off using conventional fuels and planting more forests, than fostering a switch to biofuels.

Wheat-based fuel more polluting than petrol

Published on Friday, the Academy report notes that we now understand much more about what specific crops and regions pose a high risk of land-use change and pollution. Although the researchers do say they see a role for crop feedstocks in the future, they highlight that wheat-based biofuels have been shown to have higher emissions than petrol, and recommend the government creates incentives for developing second generation fuels.  

Possible sources for second generation fuels include converted waste cooking oil, municipal solid waste, the dregs from whisky manufacture or even fatbergs (huge solid deposits which develop in sewers). The Academy paper still recommends growing energy crops (like willow and miscanthus grass), but wants this done on marginal land that is unsuitable for food production, housing or has been degraded through deforestation.

Especially where second generation biofuels are concerned, the researchers want stricter standards to be brought in; accreditation standards are currently voluntary and they said that while some bodies such as the Roundtable on Sustainable Biomass have developed comprehensive standards covering social, economic and environmental aspects, much of the industry works to minimum standards.

Despite problems associated with their use, and their preference for electric vehicles, powered using renewable energy, the researchers believe that sectors including aviation, shipping and haulage will still require liquid fuel for a long time to come, and that biofuels can play a part in this area.  The authors want a cap set on the amount of crop-based biofuels, but they don’t put forward a specific figure. The EU cap is currently 7% of the fuel mix.  

Professor Adisa Azapagic from the University of Manchester, who chaired the Academy’s working group on biofuels, said, “Second generation biofuels offer real prospects for the UK to make progress in reducing emissions from transport, particularly in sectors like aviation where liquid fuels are really the only option for the foreseeable future. Our report shows that, with the right safeguards and monitoring, biofuels from waste in particular are well worth pursuing from a sustainability point of view and also provide business opportunities for development.”