Or you use batteries which is in the default option. From the article "You can also enter your address and get an updated estimate that takes into account local costs and incentives, and add on any Powerwalls (with three as the default for a 2,000 square-foot roof)"
>Or you use batteries which is in the default option.
What batteries? Hate to break it to you, but there is no battery technology capable of storing enough energy to bridge solar intermittency gaps at even the scale of a city.
This solar roof is for single family homes, not city scale energy. You can power a single family home by building extra solar capacity so you have a surplus of energy during the day to charge batteries which you use at night. Just search for "off grid homes" to see examples. It'll most likely be more expensive at todays prices but the technology absolutely exists.
The problem with hydro is that it doesn't scale. You can build it where there is a suitable location, but most of the suitable locations already have it.
