The EU energy roadmap for 2050 aims at a 75% share of renewables in the gross energy consumption.
Achieving this target requires a significant share of alternative transportation fuels, including a 40% target share of low carbon fuels in aviation (*1). Therefore the European Commission calls for the development of sustainable fuels from non-biomass non-fossil sources.
In contrast to biofuels, solar energy is undisputedly scalable to any future demand and is already utilized at large scale to produce heat and electricity. Solar energy may also be used to produce hydrogen, but the transportation sector cannot easily replace hydrocarbon fuels, with aviation being the most notable example. Due to long design and service times of aircraft the aviation sector will critically depend on the availability of liquid hydrocarbons for decades to come (*2). Heavy duty trucks, maritime and road transportation are also expected to rely strongly on liquid hydrocarbon fuels (*3). Thus, the large volume availability of ‘drop-in’ capable renewable fuels is of great importance for decarbonizing the transport sector.
This challenge is addressed by the four year solar fuels project SUN-to-LIQUID kicked off in January 2016.
The European H2020 project aims at developing a
as a highly promising fuel path at large scale and competitive costs.
Solar radiation is concentrated by a heliostat field and efficiently absorbed in a solar reactor that thermochemically converts H2O and CO2 to syngas which is subsequently processed to Fischer-Tropsch hydro-carbon fuels. Solar-to-syngas energy conversion efficiencies exceeding 30% can potentially be realized (*4) thanks to favourable thermodynamics at high temperature and utilization of the full solar spectrum (*5).