Diesel Fuel From Air: Neat Idea, Very Inefficient Use Of Energy - Green Car Reports
It sounds like an intriguing idea: Make diesel fuel from air rather than fossil-fuel petroleum. Take hydrogen and carbon dioxide, add some energy, and voila: Carbon-neutral liquid fuel. Sunfire produced usable e-diesel at its Dresden plant in April, and Johanna Wanka, a German minister, ran the first 5 liters in her Audi A8 TDI--an event the automaker proudly promoted. Carbon Engineering has just completed a pilot plant that will produce 500 liters of carbon-neutral diesel fuel a day from 1 to 2 tons of atmospheric carbon dioxide. Synthesizing e-diesel starts with boiling water into steam, and then separating it into hydrogen and oxygen through electrolysis at roughly 800 degrees Celsius (1500 degrees Fahrenheit). the final e-diesel is created by conventional refining processes, and can be mixed with conventional diesel fuel. As the BBC notes, "The process requires electricity, but if the start-ups use renewable electricity they can produce diesel that is carbon neutral. And that's the challenge: It takes truly large amounts of electricity to produce relatively small volumes of diesel fuel. Source: www.greencarreports.com
