‘Solar’ fuel holds sustainable energy promise

At the moment the technology is still at the experimental stage, but researchers at the EU-funded SOLAR-JET project have proven for the first time that it works, and will now investigate whether it can be scaled-up commercially.

If they are successful, the breakthrough could mean that carbon dioxide, a greenhouse gas, could become the raw material for petrol, diesel and the jet fuel kerosene.

‘This technology means we might one day produce cleaner and plentiful fuel for planes, cars and other forms of transport,’ said Máire Geoghegan-Quinn, the European Commissioner for Research, Innovation and Science. ‘This could greatly increase energy security, and turn one of the main greenhouse gases responsible for global warming into a useful resource.’

The researchers used concentrated sunlight, simulated in the lab, to turn carbon dioxide and water into a product called synthesis gas, or syngas, in a high-temperature solar reactor. 

Shell, a global petroleum company, then converted the syngas into kerosene using an established technique called the Fischer-Tropsch process, a series of chemical reactions developed in 1925 by researchers in Germany.

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‘This technology means we might one day produce cleaner and plentiful fuel for planes, cars and other forms of transport.’

Scaled-up

One of the benefits of the technique is that the Fischer-Tropsch process is already being used on a global scale by petroleum companies, meaning that once the solar reactor technology is perfected, the technique could be scaled-up.

In addition, Fischer-Tropsch-derived kerosene is already approved as a jet fuel, and no adjustments have to be made to plane engines before it can be used. Nor should it be the case for cars and trucks, as the process can equally produce gasoline and diesel fuel.

‘Increasing environmental and supply security issues are leading the aviation sector to seek alternative fuels which can be used interchangeably with today’s jet fuel,’ said Dr Andreas Sizmann, the coordinator of the SOLAR-JET project.

‘With this first-ever proof-of-concept for “solar” kerosene, the SOLAR-JET project has made a major step towards truly sustainable fuels with virtually unlimited feedstocks in the future.’

Finding new, sustainable sources of energy is one of the focus areas of Horizon 2020, the EU’s latest research funding programme. 

In the first call for research proposals under Horizon 2020, the EU proposed investing EUR 732 million over two years in this area, including the development of the next-generation technologies for biofuels and sustainable alternative fuels. 

The four year SOLAR-JET project started in 2011 and is receiving EUR 2.2 million funding from the EU. The next stage will be for researchers to improve the solar reactor, and to work out whether the technology will work on a larger scale for a reasonable cost.

Animated footage of the SOLAR-JET process for producing syngas.