A while back there was an article about updating the electric grid, and I posted a controversial opinion. I believe public investment in the grid may be misguided due to continuing technological development in solar power and storage that will make the idea of the grid itself obsolete. Many voices informed me that while solar may be affordable, batteries just aren't there.
Since then, I keep seeing articles like this one on increasing battery density for decreasing price. This particular prediction is that battery tech will be cheap enough in 15-20 years. My guess is by then no one will have physical data connections to their houses either.