From what I understand, air is extracted from the atmosphere, the CO2 is separated and liquefied and turned into a fuel, to be used with hydrogen. This is supposedly, carbon neutral or "carbon-free energy". What are the waste products of using this as an energy source? Is it carbon neutral because no new carbon is being released into the atmosphere i.e. the only CO2 used is released back (net increase zero)?
The process is you take CO2 and crack it to form carbon monoxide, then you take hydrogen which is made from natural gas or from electrolysising water. The next part is called the Fischer–Tropsch process and we've been doing it industrially since the 1930s, you react the two together to make methanol which is the liquid fuel.
The downside is that you still need to put energy into it to get the fuel. So it's only carbon-neutral if you have a carbon-neutral energy source to put in. Recent developments have mainly focused on cheaper and more efficient ways to make the carbon monoxide.
>>4420 Well, the CO2 that was released as a result of combusting the methane is the same CO2 that was captured from the air; when you burn wood the CO2 that is released was captured by the tree initially.
