A pretty good article, IMO, perhaps a little pessimistic, but perhaps that’s reasonable considering all the eager optimism around. There are several things I’d like to add, though.
First, regarding the Tesla/solar ideas, is the fact that Mr. Musk’s optimism is completely unwarranted. His Tesla Model 3 is in “production hell”, due to a failure to allow for all the little unexpected problems of putting a production line together.
This isn’t the first time Tesla has failed to meet very over-optimistic schedules, and clearly Mr. Musk has failed to learn enough of the lessons from that previous events to allow enough contingency for this time.
Given that, IMO the best thing both Mr. Musk and Puerto Rico could do is drop the idea, saving Mr. Musk from diving head-first into a whole new set of problems he will lack the realism to provide contingencies for. And that Puerto Rico would suffer from.
Regarding solar prices, you should remember that the US lacks the capacity to produce the volumes of PV required, and if they are imported from China (or wherever) the costs could be much lower. (I can’t see Mr. Trump’s base, or the electorate in general, allowing him to impose punitive tariffs at the expense of a disaster victim.)
Also, remember there’s much more to an electrical grid than power, even when you’ve allowed for consistency. You also need to meet needs of ancillary services: voltage support, frequency support, and (AFAIK) phase support. While prototype solid-state support for those is under development, AFAIK it isn’t really ready for prime time.
You mentioned hydro-power, but didn’t include pumped-hydro storage. Unlike power, which is dependent on rainfall, pumped storage can re-use the same water, and be supplied from the lower reservoir level.
Energy turnaround efficiency is in the same range with batteries: 8o-90%, modern systems can run continuously, in pump, generation, and idle mode, providing large amounts of rotating inertia for frequency/phase support.
Within reasonable distances, they can also provide voltage support, as well as quick ramp times either way.
And pumped hydro is mature technology, which means the number of unexpected problems involved in deployment would be far smaller, and mostly far more familiar to engineers involved.
Finally, CCGT (which I believe you mentioned) is also mature technology, as well as being very cheap and quick to deploy. Of course, the fuel is much more expensive than coal, but that’s where solar and wind can come in, paying for themselves in saved fuel costs. Only the gas (or oil: flex-fuel is an inexpensive option) capacity would have to be installed to get people power, solar and wind could be installed on a more leisurely basis.