[megous]

It should be possible to just heat the 1l of water in a kettle and in a pot using gas, and compare the electricity and gas consumed.

Time-wise I'd think it's quite comparable, in my experience.

This of course depends on sizes and quality of kettle/pot. Wide pot, with large surface area and a quality heatspreader on the bottom will get the water boiling more quickly. Also covering a pot is a must.

Sometimes when I'm in a hurry I split the water between a pot and el. kettle, to get a boiling 2l of water faster, and there's no huge difference in time to boil.

[rini17]

Have you tried induction stove? It loses almost no heat to outside of pot and that makes palpable difference.

[SilverRed]

An induction stove is pretty much the same thing as a kettle for heating water. The OP post is against kettles because they require AC power which their solar panel and battery can not sustain.

But somehow gas doesn't have to be accounted for and just comes for free.

[ClumsyPilot]

But in this conversations its basically an electric kettle.