In that case, gas plants are the best peaker option in most places as in most place CO2 and methane emissions cost $0.

Is that a meaningful statement?

I can rephrase to say that the comparator function for money has an ideological bent. It rewards the externalization of costs

Money is a unit of measure. Any other unit of measure you choose will be fungible with it. Money is simply a way of unifying things we care about and translating them into the same space.

In order to compare two actions, you need to normalize their consequences to make them comparable. This is a fundamental requirement of making decisions. 'Money' is simply the unit we choose to do that in our complex society. We can call it utility points or something else, if you want, but it's still the same abstract object.