Do you feel a twinge of guilt every time you fill your tank with dirty gasoline? What if you could power your car with a carbon neutral fossil fuel substitute? Introducing Audi’s new e-fuel, an energy source that powers a standard engine like gas or diesel, but uses CO2 instead of dead dinosaurs and petrified algae. Seeing as most electric cars have a somewhat limited range, long charging time, and small nationwide re-fueling infrastructure, most believe that a majority of drivers will be riding around with an internal combustion engine for the next couple decades. The e-fuel has the benefit of already being able to take advantage of gas stations as well as the landfills and non-potable water sources it needs to create the compound. Here is how it works:
Forget drilling or fracking for crude, Audi’s e-gas, e-diesel, and e-ethanol take advantage of already existing sources of CO2 for production. Being carbon neutral, the fuels consume as much carbon dioxide during the manufacturing process as they expel when being burned. First, biogas is obtained from a plant that processes organic waste. Then, Audi harnesses the CO2 that would have otherwise been released into the atmosphere to make hydrogen through electrolysis powered by renewable energy sources such as wind or solar. Afterward, CO2 is added to the hydrogen to make methane and e-gas. Unlike hydrogen by itself, there are already existing national networks for methane, allowing e-gas to fill an existing infrastructure.
Audi is currently building a plant in Germany to make e-fuel and introduce the A3 TCNG, a car that can run on both e-gas and regular fossil fuels. Here in the US, e-fuel and e-diesel are being made by Audi and their partner Joule in New Mexico by using non-food crops, dirty water, and microbes. In this process, photosynthetic organisms consume sunlight, industrial waste CO2, and brackish water to excrete fuel. This way, there is no need to use valuable drinking water or agricultural land to make the e-fuel.
At present, e-fuels are facing several challenges. Audi would ideally like the price of a barrel of e-fuel to equal the price of a barrel of oil. They hope to be at around $100 a barrel by 2020 as they begin to scale up their plants. Another hurdle they have to face is yield. E-ethanol has already reached 8,000 gallons per acre, which is better than many biofuels, but still miniscule in comparison to dominance of gasoline. Also, while carbon neutral, the fuel is not actively cleaning the atmosphere, just creating a zero net output of greenhouse gasses. However, creating synthetic methane is an intriguing step towards closing a biological and mechanical loophole and one more weapon in the arsenal in combating global climate change.