Storing Energy: Elon's Big Battery Bet.
King Coal made the industrial revolution, but now it's in its dotage.
In many places, renewable power from solar and wind is already cheaper than coal. This led to a problem in Australia when an inter-grid connection went down and a big chunk of South Australia found itself without backup for those times when the Sun doesn't shine. Enter Elon Musk with an offer the down under couldn't refuse - 100 MegaWatthours* of energy storage in 100 days or it was free. At a bargain $250 kWhr.
I don't think Trump or anyone can save coal now. I would not be surprised if grid storage increases by a factor of 100 in the next five years.
Phun Phacts: 1 Whr is 3600 Joules, so 100 MWhr is 3.6 x 10^11 J, or roughly the energy in 15 metric tons of coal, which doesn't sound like a whole lot. A big coal burning power plant costs $1 billion plus and can produce a GW (1000 MW) of electricity. Musk's 100 MWhr array would only store about six minutes worth of the output of such a plant. At several points during the crisis, though, prices reached the legal maximum of $14,000 per kWhr. At prices like that, your 100 MWhr grid storage can pay for itself rather quickly.