Why green electricity contracts fail to deliver green electricity

Counterpoint:

If the money you pay for electric power ends up paying for the operation of green electricity generation, that's enough.

It's enough because anyone who wants to operate a coal-fired plant without income has a problem and will stop soon enough. You don't have to make that coal-fired plan your problem or split hairs about kinds of greenery, because the beancounters will take care of it.