And it’s not as if the world has been standing still over the last decades, huge progress has been made and many technologies are at the borderline of being economical or cheaper than the alternatives, and are continually falling in price. Once we push the boulder over the crest of the hill it will roll down unaided. The economy can change much quicker than we think.
I agree that many technologies for replacing fossil usage have now achieved or are close to economic superiority, and that change can come very rapidly with economic superiority. But I also think that reaching this point has taken too long and now we will need active measures as well as emissions cuts.
So, due to these different marginal costs, there's no way even completely practical, economical solar can stop fossil fuel usage quickly without active regulator intervention.
Note that there is also quite a bit of already-built fossil capacity that can be retired early by economic pressures. Not every big fossil project has operational costs as low as Saudi oil.
For example, the Navajo Generating Station is the largest American coal plant west of the Mississippi River. It was built in the 1970s. It has a stable, low cost for coal since it is supplied by the nearby dedicated Kayenta Mine. Just a few years ago it was planned to run until 2044. But the falling costs of gas and renewables have made it economically uncompetitive. It's now going to close at the end of 2019, 25 years early:
https://www.azcentral.com/story/money/business/energy/2017/0...
I agree on the broader point that fossil fuel emissions won't be curbed quickly without active regulator intervention. Since that intervention may arrive late-or-never in different nations, it's one of the reasons that I believe active carbon dioxide removal measures will be necessary in addition to emissions reduction efforts.
Operators, by the way, love this concept. It means they can continue production basically forever, if they want. But there's a big economic disadvantage in being the first mover, which is why we need government regulations forcing it.
If you do something fairly extreme for curtailment, like a tax on fuel that motorists really notice, the other party will get voted in and they'll undo it. Now you've got kicked out of office, with no environmental benefit to show for it.
And if you go further with something like a ban on pet dogs or ban on meat-eating? Same thing but faster and with more certainty.
