Renewable energy is the future. But hydrocarbon-based fuel is still indispensable. There is no definitive replacement in sight. Now, all this could be turned upside down. A method has been invented to create fuels from carbon dioxide (CO2), water and sunlight. It is the system that creates fuel from air. The results are in the journal ‘Nature’.
Photosynthesis in reverse
They are less famous alternative energies than wind or solar. But they can be very useful in the short term. For example, synthetic fuel. A fuel without emissions that is made from carbon dioxide and hydrogen. From sunlight they create a hydrocarbon chain. It can be transformed into fuels suitable for combustion engines.
It was proposed by Aldo Steinfeld’s team at the Swiss laboratory ETH Zürich. It ‘reinvents’ the natural process of photosynthesis. Plants absorb atmospheric CO2 and water. And, with sunlight providing the energy, they convert these raw materials into organic molecules. And that’s how Steinfeld’s prototype works.
The device absorbs CO2 and water from the atmosphere and stores them. It comes in contact with a basaltic rock and absorbs the unwanted carbon. The second step involves energy from sunlight. It heats cerium oxide which reacts with both CO2 and water. The reaction with CO2 creates carbon monoxide. Hydrogen is created from water.
The byproduct (or residue) is oxygen, which is vented to the atmosphere without a negative impact. What remains is a mixture of carbon monoxide and hydrogen. It’s called synthesis gas, and it’s used to make many things like diesel.
“The individual steps of the solar fuel production process were known. Having the system optimized under real-world conditions is a challenge,” say the authors.
The prototype was installed on the roof of the ETH Machine Lab Building. It produced 32 milliliters of pure methanol for every seven hours of work each day. Proof that the system is viable. How much would it take to supply the actural fuel required? About 45,000 square kilometers of suitably isolated land. Approximately 0.5% of the area of the Sahara desert.
The cost of initial investment in the first plants “would exceed that of the fossil kerosene it is to replace.” It requires “policy support to reduce pollutants”. That is, investment support for a new, cleaner fuel.
The system that creates fuel from air is on its way. Undoubtedly, new alternatives for a new world that needs them.