CO2 fraud has been uncovered in the EU VAT zone[0] 1.6 billion euros skimmed by a dozen people in France. Up to 10 billion for the EU as a whole.

Unfortunately I could only find sources in french or hebrew but the amounts amassed by this operation is staggering.

[0]https://fr.m.wikipedia.org/wiki/Fraude_%C3%A0_la_TVA_sur_les...

Can't we make fines high and give anyone that reports fraud a cut of penalty?

There's a similar concept to a Pigovian tax for fines, I think of it as a "Pigovian fine", which is the price at which the likelihood of getting caught times the fine exceeds the cost to pay the tax directly.

So if you have a 1% chance of getting caught, the fine needs to be 101x the tax.

This is why so many e.g. banking and consumer protection fines fail to achieve their goal - the cost of adhering is more than the probability of getting caught times the fine, so it's economically rational to not pay.

Not just simple fraud, but a major hurdle is how to regulate CO2 necessary for producing consumer energy without creating a regressive tax structure. Once CO2 is converted to electricity on the grid, it's fungible and impossible to sort out luxury vs necessity.

Imho, government trying to sin-tax away CO2 is result of our failure to invest in technology solutions.

Not so hard. It's fine if any individual tax is regressive, as long is counterbalanced by UBI or other forms of per-capita welfare support. You don't need to measure precisely, as long as you get rough estimates that people pay $Y in various sin-taxes but get $X>$Y in general welfare benefits.

I absolutely disagree. Inserting the government into the average citizen's balance sheet can and will be corrupted.