Porsche is replacing gasoline with air and water | Fox News
You can't beat the laws of Thermodynamics. You always lose energy in the transformation from one form to another.
Apparently though they are using the constant high winds to provide the energy to make the methane. So, who cares if you lose some wind energy? Wind energy costs are essentially limited to the windmill costs. Base materials are water and carbon dioxide, both essentially free and inexhaustible. It's pricey now but costs will come down. Lithium batteries and coal generated electricity ain't cheap either.
If Porsche starts winning races on the methane fuel and if, as they say, any current gasoline car can use it....winner, winner....chicken dinner.
We shall see.