Imperial College London 

Keynote Speaker


Bill Rutherford of Imperial College London is a biochemist/biophysicist who studies the bioenergetics of photosynthesis: solar-driven, biological energy-conversion. He did his BSc in Biochemistry at the University of Liverpool, his PhD at University College London. He did post-doctoral work at i) the University of Illinois, ii) Riken, Saitama, Japan and iii) CEA Saclay, near Paris, France. He joined the CNRS as a researcher at Saclay, becoming head of the CNRS unit and then of the Service of Bioenergetics CEA, before moving to Imperial College in 2011 as the Chair in Biochemistry of Solar Energy. His interests and contributions include structure/function aspects of the water splitting enzyme and photosynthetic reaction centres, proton-coupled electron transfer, evolution of photosynthesis, photochemistry, mechanisms of photoinhibition, redox tuning, bioinorganic chemistry, molecular enzymology of water splitting, long wavelength oxygenic photosynthesis, artificial photosynthesis, and energy accounting. He is a member of EMBO, was awarded the Medaille d’Argent du CNRS in 2001, was the Craig Professor of Chemistry at ANU Canberra in 2005, a Visiting Professor at Queen Marys College London 2007-2011. He was the president of the International Society of Photosynthesis Research 2011-2013 and was awarded an honorary Doctorate in Chemistry from Uppsala University in 2013. He was elected a fellow of the Royal Society in 2014. He is also active in accessing the feasibility of policies aimed at mitigating the climate crisis. Publications: ~273, (refereed journals: 219, others >50). Metrics: Google Scholar h-index 86 (>19,000 citations). Web of Science h-index is 73 (>14,600 citations, ~53 average citations per item)

Google scholar: https://scholar.google.co.uk/citations?user=aogee_YAAAAJ&hl=en
ResearcherID: http://www.researcherid.com/rid/A-7831-2019
ORCID: https://orcid.org/0000-0002-3124-154X 

Reality Checks for Biofuels as Replacements for Fossil Fuels: Sustainable Avion Fuels as a Case Study.

A.W. Rutherford*, H. Raine, A, Fantuzzi 

Imperial College Londo, United Kingdom Institution

Keywords: sustainable aviation fuels, life-cycle analysis, energy accounting, resource scaling


Aviation is a difficult sector to decarbonize due the energy density needed in jet-fuel. To be a legitimate replacement for fossil fuels, an alternative fuel must result in significantly smaller net emissions of green-house gases (GHG) and should be energy efficient, as estimated by GHG and energy Life Cycle Analyses (LCAs). The production of the fuel must also be scalable to the level of the fuel demand and feasible in terms of the resources required. Here we analyzed the options for decarbonizing aviation focusing on a range of alternative fuels.

We performed GHG and energy LCAs for bio-jet fuel production from rapeseed grown in the UK. We analyzed the extensive literature covering this and other bio-feedstocks (energy crops, agricultural and forest waste) and fuel production processes. We also estimated the resources needed to make bio-jet fuels at scale. For energy crops, we used the land area needed for their production as a scaling measure. For waste, we compared the fuel requirement with the amount of existing and/or available waste.

We also did scaling calculations for hydrogen, ammonia, and artificial hydrocarbon fuels (e-fuels), all of which are considered future alternative jet fuels. In addition, we considered the option of continued fossil jet fuels-use but with a compensatory level of carbon capture. For these cases, we took “sustainable” electricity use (solar and wind power), as the main energy resource and as a feasibility measure at scale.

LCAs data for energy crop-based bio-jet fuel are scattered, but if extreme outliers (both good and bad) are ignored, and we take only the relevant, real-world scenarios, some small savings in GHG may be made. But these do not hit targets for sustainability (e.g., EU renewable energy directive RED). When bio-jet fuels are blended with fossil fuel, as currently required, the GHG savings become barely significant. The scaling results are clear: bio-jet fuel production at scale from energy crops requires unfeasibly large areas (~68% of UK agricultural land), and when scaled down to be feasible, they have a negligible effect on GHG emissions, while being a disproportionate drain on resources, not least by competing with food, and also damaging the environment.

For biowaste feedstocks, the LCAs are dubious as most “waste” is not waste: it has other uses. Thus, replacements of current uses must be accounted for in the LCAs. Scaling to the required amounts of jet fuel shows that in most cases, there is far too little waste to be significant.

For H2, NH3 and e-fuels production, huge amounts of sustainable energy are needed. This is also the case for carbon capture to compensate for current fossil fuel use.

The present assessment needs correcting to account for CO2 emissions making-up ~1/3 of the GHG emissions from aviation while NOx and con trails make 2/3. This multiplies the problem by 3. There is no technological silver bullet, thus higher costs and demand reduction seem inevitable.

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