Hmm, I seem to have killed the thread

Let's try again ...
Allowing every consumer their own personal energy (carbon) allowance at reasonable cost, and after that has been spent on fuel and energy, extra credits can be bought at much higher cost.
Absolutely agree with the first part. Suggest that the cost is zero if the allowance is 'reasonable'

And 'consumer' needs to be defined to exclude energy tourists.
But the key bit is this "extra credits can be bought at much higher cost". Specifically, the
only way to buy extra credits should be from somebody else who has them. The market can settle the price.
But buying a credit from somebody who subsequently dies through 'fuel starvation' should be a criminal offence punishable by life!