You are of by a factor of ten: 108,000,000/34,000,000,000 = 108/34,000 = 0.003-ish m^3, or 3 liters of gas to produce those 30kWh. That is in line with http://en.wikipedia.org/wiki/Gasoline, which claims 9.7kWh/l. So, the volumetric difference between battery and gas is 30, not 3. If it were only a factor of 3, as in your calculations, I think all cars would be electric by now.