Also another thing to factor in,, Assume you are the Builder and...

Also another thing to factor in,, Assume you are the Builder and the owner of a big Highrise you plan to build and rent out the offices in the City.

To get the rents you want then you would need to be able to guarantee power supply 24/7 regardless of what happens to the City Grid Power. Like what If a Train derailed at the station and your Highrise was 100 meters away. What if the Power needed to be turned off in your zone to make it safe for rescue workers to get in and repair the damage to who knows what.

So regardless of what mad event hypothetically could happen, but your Building needs a power supply to keep the elevators running, and lights and ventilation all running.

So you would have planned to have a power back up for your Building or else you could be responsible or liable for any loss the Businesses that rent off you lost while power was off.

So if you had to ensure power back up, then Batteries would be one of your options, and also sourcing a power supply to keep those batteries charged would also be something you would consider.

So batteries in Buildings will be a thing in the future, even if its just to charge them at off peak power rates and draw from them at peak power times.

Having a source of Power outside of the grid is good insurance when planning a Modern Future Building regardless of the payback rates, the value of having that power sorce stored if the Grid was down would add viability to choosing solar Glass.