As far as I understand the alternative candidate is Methanol, which can be produced from Hydrogen, which has a relatively high energy density, is liquid at room

As far as I understand the alternative candidate is Methanol, which can be produced from Hydrogen, which has a relatively high energy density, is liquid at room temperature, and works well with fuel cells. https://en.wikipedia.org/wiki/Methanol_economy https://en.wikipedia.org/wiki/Methanol_economy