Last week, Air Fuel Synthesis (AFS), a company in Stockton, UK, revealed the first successful demonstration of an idea that dates back to the oil crisis of the 1970s: that carbon, hydrogen and oxygen can be plucked from carbon dioxide and water in air to be converted into methanol and then morphed into gasoline.
However, amidst the headlines, some media coverage overlooked the key point: the energy efficiency of the process has yet to be demonstrated. This matters because the technique uses electricity for key stages. It should not require more energy input than is gleaned from burning the fuel it produces.