Published October 01, 2012
Automakers are desperately trying to lower the carbon dioxide emissions of their vehicles, but what if they could just figure out a way to run their cars on C02, instead?
That’s what Audi is planning to do with its new e-gas project, which will produce a synthetic fuel made from carbon dioxide and hydrogen. The resulting fuel is methane, the main component of natural gas, but created here in a novel way.
Audi is building a pilot facility in the U.K. that is powered by windmills and can produce hydrogen from water through the process of electrolysis. That gas can then be used to fuel electric cars that get their energy from hydrogen fuel cells, but since that technology is prohibitively expensive for mass production today and the infrastructure to distribute hydrogen has not yet been built, Audi has figured out how to make it more useful in the meantime.
Methane, which has the chemical formula of CH4, is often manufactured through the decay of organic waste, but the process generates a large amount of carbon dioxide. Instead of releasing this into the atmosphere, the excess C02 from one of these plants will be transferred to the e-gas facility where it will be combined with hydrogen to create even more methane.
From there, this synthetic fuel can be pumped into the existing natural gas infrastructure for use in cars -- distributed through compressed gas refueling stations or pumps installed in homes. Audi will begin selling a bi-fuel version of its A3 compact in Europe next year with a four-cylinder engine that can burn either methane/CNG or gasoline.
Carbon dioxide will still come out of the A3’s tailpipe when it is running on methane, but it will be the same amount that was used to create the gas, so there will be no net increase in the amount of C02 released into the atmosphere. Audi is working on a system that will allow drivers to purchase offsets tied to the synthetic fuel.
Perhaps more important, the transference of energy involved in this method facilitates a way for cars with existing internal combustion engine technology to indirectly run on the electricity that was used to produce the hydrogen molecules in the methane, alleviating some of the issues caused by battery performance that has yet to catch up with consumer desires for range, recharging time and price.