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Two weeks ago, we read about agave as an alternative feedstock to corn or sugarcane in the production of bioethanol fuel in Mike’s story Tequila for your fuel tank. In it, Mike describes research by David King from the Low Carbon Mobility Centre at the University of Oxford and his team.
At the same time, King’s team has been busy putting research together to show that algae-derived biodiesel ‘could be the answer to the fossil fuel crisis’. Indeed, airlines have already been testing a range of biofuels in their planes, including algal-derived biofuels.
Algae grow in the sea or wastewater, so production wouldn’t affect land that could otherwise be used to grow food crops, unlike other biofuel sources. Also, algae remove carbon dioxide from the atmosphere by photosynthesis, offsetting carbon dioxide released during fuel combustion. But algal biodiesel production is currently 2.5 times as energy intensive as conventional diesel, so it hasn’t been a viable alternative.
So what does King propose to get around this problem? His team has investigated the ways that every step of the production chain can be optimised to use low-carbon energy sources and to produce considerably lower
amounts of greenhouse gases than conventional diesel.
They did this by looking at the fossil fuels consumed and greenhouse gas emissions at each stage of production – feedstock farming, biomass harvesting and drying,
algal oil extraction, feedstock conversion, fuel distribution and combustion by the end user.
The team concludes that running costs can be reduced by off-setting heat and electricity used in the processes by putting waste products formed – oilcake and glycerol – to good use, such as in livestock feed. They suggest minimising the carbon footprint by sourcing the energy needed for fertilisers, transport and building materials from low carbon sources.