[nivenkos]

I see it more as a reasonable way of shaping behaviour. Like taxing diesel, cigarettes, alcohol, etc. is fair enough if it helps create a better society.

Taxing electricity whilst trying to encourage people to switch their homes from gas and their cars from diesel, is just crazy.

[pessimizer]

You then run into the question of whose vision of a better society you're enforcing. But aside from that you can really look at those taxes as something to offset the additional costs of commerce in those things. We've agreed that emissions are a danger, cigarettes raise health care expenditure, and alcohol raises police expenditure. We use those to justify the specific amounts of the taxes.

If this weren't the justification, there's no reason not to just ban the things you don't approve of altogether, rather than just taxing them.