[MRM]

Now pair the hotter SkyActive-X engine with a steam engine that can capture all that excess heat that would be otherwise lost and you have an internal combustion engine that will have incredible efficiency.

The reason it's so hard to get away from fossil fuels is basic physics. There is so much energy packed into a gallon of gas, it is so transportable, and it's so easy to convert, that it's hard for other fuels to compete. Fossil fuel technology continues to improve even as alternative energy technologies develop. Alternatives are going to have to experience a quantum leap in technology to truly replace fossil fuels.