The Synfuel research project brings together electrolysis and pre-gasification, and can transform biomass and wind energy into ‘green’ methanol, which can be used as bunker fuel and, after upgrading, as a substitute for diesel and jet fuel.
Biomass and wind turbines are the main sources of renewable energy in Denmark – and both still hold considerable potential for significantly expanding production. When optimally located, wind energy currently prices competitive to fossil fuels, which makes it realistic to deploy many more wind turbines in the coming years. At the same time, Denmark has—in particular from forestry and agriculture—large volumes of surplus biological products, for example, straw, which are currently only being used to a limited extent in energy production.
However, even though there are obvious possibilities for increasing production, use of the two energy sources has so far been limited, explains Professor Peter Vang Hendriksen from DTU Energy.
“It’s true of both wind energy and burning biomass that output in the form of power and heat is difficult to store and cannot be used for either air or maritime transport. Therefore, today we use fossil fuels almost exclusively in heavy transport, and also to a significant extent when making up the shortfalls in power supplies from wind. This in turn is making it difficult to achieve the goal of a carbon-neutral energy sector, and it is also a big challenge for the transport sector to live up to its share of the 70 per cent reduction in carbon emissions by 2030.”
A solution for carbon-heavy transport and shortfalls in renewable energy
A solution that can store energy from biomass and wind and which can be used to produce sustainable fuel for aircraft and ships therefore represents a major step forward in terms of the climate in general. And it is precisely this kind of solution that the Synfuel project is offering, with the backing of Innovation Fund Denmark:
“In the Synfuel project, the hydrogen from a Solid Oxide Electrolysis Cell (SOEC) is used to synthesize a liquid ‘green’ fuel after it has been mixed with synthesis gas extracted by means of thermally pre-gassing straw using a Pyroneer pre-gasification plant,” explains Senior Researcher Jesper Ahrenfeldt from DTU Chemical Engineering.
Synfuel is thus combining two technologies, where the energy for the first comes from electrical power, and the energy from the other from straw, for example. And because the two production forms have clear synergy effects and can use each other’s ‘waste’ products, it achieves an unprecedented high level of efficiency:
“Synfuel is the first experiment to have demonstrated that hydrogen from photocatalytic water splitting in the synthesis of methanol can be used to prolong the biomass resources, at the same time that the oxygen which is produced in the electrolysis part is used in the pre-gasification process. This achieves higher utilization rates for the two technologies than when they are running independently. We derive more biofuel from the biomass resources, and at the same time we can use surplus power from wind turbines, for example, to make fuel for heavy transport,” says Peter Vang Hendriksen, adding:
“We’re thrilled that the technologies operate smoothly together, and that it is possible to run the electrolysis stack ‘thermo-neutrally’. This means that the electrolysis process doesn’t produce any waste heat, but that all electrical input becomes chemical energy.”
And Rainer Küngas, Principal Scientist at Haldor Topsøe A/S, who, together with DTU, has developed the SOEC cells which are used in the electrolysis stack, says:
“The project demonstrates that the SOEC technology can play a key role in future energy scenarios where there will be even more focus on carbon emissions from those industries and sectors using liquid fuels.”
Promising business for enterprises, society, and climate
Even though the combined system still needs to be upscaled, Jesper Ahrenfeldt believes that the starting point of two known technologies will make it possible to quickly mature the Synfuel technology and integrate it into the Danish energy system.
Researchers from DTU Management, who have analysed the technology’s potential in the Danish energy system, are unanimous in saying that it’s only a matter of time before Synfuel’s technology can produce significant results in terms of lower carbon emissions, and that it will be an advantage for Denmark to accelerate the process, because it can become a promising business for enterprises, society, and the climate.