Obviously TANSTAFL but the clear point here is you can burn coal only once. Solar panels + Li-ion can be reused atleast 500 times (assuming standard Li-ion batteries that crap out after 500 full cycles).

yeah no kidding. It would have been a diversion to mention solar; which Musk is also betting on, not co-incidentally.

Solar in similar: it depends utterly on the whole industrial infrastructure, but is not continually tied to the grid like a power line.