Friday, September 12, 2014

Zero-carbon fuels in sight as Climeworks unveils industrial Direct Air Capture system

In their latest technology milestone, VEC finalists Climeworks have unveiled the “CO2 Kollektor”, their first industrial-scale CO2 capture module, at the 2014 Swiss Energy and Climate Summit in Bern earlier this month. Through their partnership with Audi’s synthetic fuels programme, we may see the world’s first fuels produced directly from atmospheric CO2 as early as 2015.


Climeworks’ newly unveiled system in the flesh – this collector will provide the first stream of air-captured CO2 for Audi’s synthetic fuels plant. Credit: Climeworks

Climeworks has been busily developing its CO2 capture technology since it was spun out of ETH Zurich in 2009. Over years of research and testing, they have developed a system that captures CO2 from air using a chemical sorbent, and then release that CO2 when heated to about 95 degrees Celsius to give a concentrated stream of over 99% purity.

For Audi, this is the ideal building block for their efforts to create a carbon-neutral synthetic fuel. Using renewable electricity generated specially for the purpose, Audi will combine this CO2 with water to exactly reverse the process of fossil fuel combustion, turning this “waste product” back into synthetic methane, known as “e-gas” that can be used in Audi’s Compressed Natural Gas (CNG) vehicles. Since the carbon in the fuel tank was itself drawn from the atmosphere, burning it in the engine simply releases it again. It’s a closed cycle in which no new CO2 enters the atmosphere. Audi are also working on processes to one day produce “e-ethanol” and “e-diesel” through the same route.

Audi e-diesel

Audi’s existing e-gas plant in Werlte, which is already producing synthetic methane from electricity, water and waste CO2 from a nearby biogas plant. Credit: Audi

Synthetic fuels have one particular advantage over batteries or hydrogen as a route to low-carbon transport: by dropping in exactly where fossil fuels are used now, they can reduce emissions dramatically without the need for major new infrastructure or changes in consumer behaviour, which may be decisive in certain cases. In the longer term, other clean hydrocarbon fuels are also likely to be important for cutting emissions from aircraft, shipping and long-distance freight vehicles that are more difficult to electrify.

Audi already have a small e-gas plant operating in Werlte, Saxony, which uses waste CO2 from a nearby biogas plant. But there are limits to how much biogas-derived CO2 will be available in future and scaling up would require a lot of biomass to be grown and transported to the plant, so Audi are keen to cut out the biogas middleman. Now they want to replace the biogas feed with Climeworks’ industrial system in 2015.

With this latest development, Audi are gearing up to place Climeworks’ technology at the heart of their synthetic fuels programme. Using waste heat from their plants, they can capture the CO2 they need on site anywhere in the world. It open up the path to producing not only e-gas at large scale, but one day synthetic diesel, ethanol, gasoline and maybe even plastic components from renewable energy, water and air. They are now committing substantial investment and industrial experience to driving the Climeworks CO2 Kollektor to maturity in order to one day bring economically viable, carbon-neutral synthetic fuels into the mainstream.

So this latest announcement is good news for Audi and Climeworks, good news for low-carbon synthetic fuels and good news for the future of economical Air Capture technology.

By Guy Lomax