[capitainenemo]

Well, there's also burning regular fuel in a fuel cell, a FCEV. That doubles the efficiencies over ICE, so I guess that bumps it back up to 8x away?

Given the great energy densities and stability in transport of hydrocarbons, there's already some plants out there synthesising them directly from green sources, so that could be a solution if we don't manage to increase battery densities by another order of magnitude.

[WalterBright]

> there's already some plants out there synthesising them directly from green sources

I didn't realize that a "green" carbon atom is different from a regular carbon atom. They both result in CO2 when burned.

[fc417fc802]

The problem isn't CO2 it's pulling carbon out of geological deposits. Thus the carbon atoms in synthetic fuel can be considered "green" provided an appropriate energy source was used.

[defrost]

> I didn't realize that a "green" carbon atom is different from a regular carbon atom.

Easy mistake to make, don't beat yourself up over it.

It's not the individual carbon atoms that carry the signature, it's the atoms in bulk that give the story ... eg: 6 x 10^23 carbon atoms

See: https://pmc.ncbi.nlm.nih.gov/articles/PMC7757245/

[jeffbee]

Its the time shift. Burning a plant releases CO2 and it is still considered to be carbon neutral.

[TheSpiceIsLife]

And, the two major byproducts of burning hydrocarbons are water and carbon dioxide.

Literally essential plant nutrients, essential for life.

Tangentially related, the 2022 Hunga Tonga–Hunga Haʻapai volcanic eruption ejected so much water vapour in to the upper atmosphere, it was estimated to have ongoing climate forcing effects for up to 10 years.

Water vapour is a stronger greenhouse gas than carbon dioxide.

And we heard precisely nothing about that in the media other than some science specific sources at the time and nothing on an ongoing basis.

From Wikipedia:

The underwater explosion also sent 146 million tons of water from the South Pacific Ocean into the stratosphere. The amount of water vapor ejected was 10 percent of the stratosphere's typical stock. It was enough to temporarily warm the surface of Earth. It is estimated that an excess of water vapour should remain for 5–10 years.

https://en.wikipedia.org/wiki/2022_Hunga_Tonga%E2%80%93Hunga...