Air + water = fuel?
October 24, 2012
British company Air Fuel Synthesis has unveiled a process by which it says it can extract carbon dioxide (CO2) from the air and combine it with hydrogen from water to create methanol, which can be converted into petrol to fuel cars and planes.
It sounds like a joke.
But the technique could eventually play an important role in the green energy mix of the future - provided the electricity used to extract the molecules and create the chemical reaction comes from sustainable sources.
Energy intensive
Getting this far has taken almost two and a half years and cost $1.6 million (1.23 million euros), provided by two private investors.
Peter Harrison, chief executive officer of the Darlington-based start-up, says "the process does use energy to take CO2 from the air," but that energy savings could be gained by using leftover carbon from brewing and distillery processes.
"Quite a lot of point-source carbon is available" for recycling into methanol production, says Harrison. "If we can find people with spare CO2, then we don't need to spend all the capital on air."
The most energy intensive step is electrolyzing water to extract the hydrogen.
"We lose about 70 percent of the energy at this step," says Harrison. This means that of all the energy used in the process, only 30 percent is left in the final product.
And the water going into the electrolyzers has to be pure – which could be a problem as water scarcity issues rise.
Sven Teske, the renewable energy director of Greenpeace International, describes the newly developed process as "an interesting option."
Teske says it's important, though, that production of the fuel is efficient and that the electricity needed for it comes from alternative sources.
Conservation of mass
Teske is also quick to point out that describing the fuel as coming from air and water is too simplistic.
"You cannot get energy out of nothing. That would be nice, but it goes against physics," says the engineer and suggests the process could better be described as "storing the energy which comes from electricity in a liquid fuel."
He goes on to say that the energy needed for the process would have to come from alternative sources, such as solar or wind power. The best scenario would involve using surplus energy from electricity grids at off-peak times, explains Teske.
Under such conditions, says Harrison, "we are actually capturing renewable energy and storing it."
Green potential
Harrisonclaims the synthetic petrol is itself clean and green because it generates no toxic by-products, such as sulfur which is left over from fossil fuel refining.
Capturing carbon dioxide from the air could present another potential climate benefit by extracting greenhouse gases from the atmosphere, Harrison says. A plant producing 1,000 tons of "air fuel" would extract up to 1 million tons of CO2 every year.
The process of converting methanol into petrol emits heat and methane, and this could also be put to productive uses as well, adds Harrison.
According to Teske another environmental advantage would be that we could continue to use existing infrastructure and technology - rather than having to build something new - as is the case with electric cars.
"Infrastructural changes make it difficult or even impossible to switch all cars" to fuel-cell technology, says Teske. "In the long run, we need an energy mix - big trucks, ships and planes can't run on batteries, a combustion engine is the better option in such cases."
The next step for the air fuel is to build a plant for production in the motorsports sector. Its good octane rating makes it well suited for high performance, says Harrison.
"This is an opportunity to create whole new industries and jobs," Harrison says.
A report released on Wednesday (24.10.2012) by Greenpeace and other groups predicts Europe will gain nearly half a million extra energy sector jobs by 2020 if it prioritizes a system of renewable energy and efficiency over nuclear power and fossil fuels.