[BobL]

“DC power doesn’t transmit across long distances well. My solar array, inverters, and battery stack have to be somewhat close to each other. I’m sure the same is for grid battery storage.”

Agree on (battery) DC power not doing well at long distances, but grid-scale battery power ALWAYS gets inverted to 60 Hz, somewhere close, and then tied into the grid, and there are high voltage power lines running all over the country where it could tie-in. So why not invert the power near the batteries and tie-in next to a power line in the middle of Nevada, or wherever there are few people around?

[Tell It Right]

The solar on the rooftops comes in as DC power, then is stored as DC power. Thus, the battery storage has to be near the solar panels (on the rooftops and parking decks of NYC, if they proceed with that plan). There's loss when converting DC to AC (at my home about 7%). So if the solar DC in the urban area was to convert to AC to transmit it out of town, then convert it to DC to store it, then convert it back to AC when needed for the grid, that's a total of 3 conversions from DC to AC to DC to AC.

But a one-time conversion from DC to AC can happen if the battery storage is in the urban area near the solar panels (again, assuming the solar is on the urban rooftops like in the link I provided). In that situation, solar power comes in as DC, stays DC to be stored in the nearby storage facility, then goes through a conversion from DC to AC only once.