Thu 13 June 2019 – A project funded by the EU and Switzerland claims to have made a breakthrough in producing renewable jet kerosene from sunlight, water and CO2. The SUN-to-LIQUID project follows on from an earlier project, SOLAR-JET, that developed the technology to achieve the first-ever production of solar jet fuel in a laboratory environment. Researchers have scaled up the technology for testing in the field and a unique solar concentrating plant has been built at the IMDEA Energy Institute in Spain, resulting in the first synthesis of solar kerosene. A solar reactor, developed by project partner ETH Zurich, produces synthesis gas that is processed through an on-site gas-to-liquid plant, developed by HyGear, into kerosene. The partners claim a 90% reduction in net CO2 emissions compared to conventional fossil-derived jet fuel and given the abundant feedstock that does not compete with food production, they say it can meet future fuel demand at a global scale.
The SUN-to-LIQUID four-year project, which finishes at the end of this year, is supported by the EU’s Horizon 2020 research and innovation programme and the Swiss State Secretariat for Education, Research and Innovation. It involves leading European research organisations and companies in the field of solar thermochemical fuel research. In addition to ETH Zurich, IMDEA Energy and HyGear Technology & Services, other partners include the German Aerospace Center (DLR) and Abengoa Energía. Project coordinator Bauhaus Luftfahrt is also responsible for technology and system analyses and ARTICC International Management Services is supporting the consortium with project management and communication.
“This technological demonstration can have important implications for the transportation sectors, especially for the long-haul aviation and shipping sectors, which are strongly dependent on drop-in hydrocarbon fuels,” commented project coordinator Dr Andreas Sizmann of Bauhaus Luftfahrt. “We are now a step closer to living on a renewable ‘energy income’ instead of burning our fossil ‘energy heritage’. This is a necessary step to protect our environment.”
The core solar technology and the integrated chemical plant have been experimentally validated under real field conditions relevant to industrial implementation, reported Prof Aldo Steinfeld of ETH Zurich, who is leading the solar thermochemical reactor development.
Explained Dr Manuel Romero of IMDEA Energy: “A sun-tracking field of heliostats concentrates sunlight by a factor of 2,500 – three times higher than current solar tower plants used for electricity generation.”
This intense solar flux, which is verified by a flux measurement system developed by DLR, allows reaction temperatures of more than 1,500 degrees C to be reached within the solar reactor positioned at the top of the tower. The reactor produces synthesis gas, a mixture of hydrogen and carbon monoxide, from water and CO2 via a thermochemical redox cycle, and then processed through the gas-to-liquid plant to produce the kerosene.
During the SOLAR-JET project (see article), a total of 291 stable redox cycles were performed that yielded 700 litres of high-quality syngas, which was compressed and further processed through Fischer-Tropsch synthesis into a mix of naphtha, gasoil and kerosene. The SUN-to-LIQUID initiative involves a more than 12-fold scale-up of the complete solar fuel production plant and integrates for the first time the whole production chain from sunlight, water and CO2 to liquid hydrocarbon fuels.
The partners say the plant will run on a daily basis over a period of months under realistic steady-state and transient conditions relevant to large-scale industrial implementation. They add that a road-map will be established for competitive drop-in fuel production from the technology.