Does it make sense to have off-grid solar in parking lots to charge cars?


Generally it doesn't make sense (and isn't that green) to have off-grid solar compared to grid-tied solar. However, a new company sells a self-contained solar EV charging station for parking lots which they claim is cheaper than on-grid, because you can just get it delivered in one day with no permits, planning, wiring or construction.

It's true that all those factors are now the biggest element of charging and solar installations.

I examine this in a article at Does it make sense to have off-grid solar in parking lots to charge cars?


Why can't ev car companies figure out how to have a built in solar panel on the roof of the ev?

The charging would be self contained within the vehicle and would only require plug in during the night and overcast days. The car could charge itself while going down the road during the day making able to travel farther during daylight hours.

Solar panels on car roofs makes little sense because it is more difficult to mount them on a car roof than in a field. Secondly you would not deliberately leave your car out in direct sunlight because of the damage UV does to paint, vinyl and upholstery.
Solar is also diffuse, so you don't get a lot of charge out of it.
I can't see any way that local solar is better than buying solar off the grid. A large scale solar power array is bound to generate cheaper power than a small local one.

In a number my articles, particularly the one on the Aptera, which is the only car this even remotely makes sense for, and even then not really. It's anti green, provides almost no energy while driving but maybe could reduce plugging in a bit because that vehicle is efficient. It would not make much difference on larger cars. If you park your car in the sun all day (which you may not want to do and may not be able to do) you might pick up 5 miles of range.

Except for very remote areas, I cannot see where locally produced solar is better than solar produced at industrial scale by a solar farm.
Panel installation is more expensive. If completely off grid, battery backup would be prohibitive to guarentee service. If connected to the grid (in both directions) storage is not required, but that in itself is expensive. Why would you not just build more solar farms, and connect chargers to that?
The grid would require less storage as a percentage of capacity than a local installation due to the complementary generation using all of solar, wind, hydro (pumped or otherwise), nuclear, heat storage, and others.
I fail to see the attraction of rooftop solar of any sort, and surely if incentives are needed (not a given) they would be better given to large scale generation companies/SOEs.
What have I missed?

Industrial scale installs are indeed cheaper.

Local solar benefits from getting free real estate (your roof) but most of all from not needing to pay for the distribution network. Today the distribution network here in California costs a lot more than the power generation.

This is so true that even going off grid makes sense to some people, and it should not.

I had assumed transmission for the producer was much lower than generation cost. Apparently this used to be the case.
But it appears they are almost on a par 4.3 for transmission vs 4.6cents/kwh for generation.
Regardless it is odd that Californians are charged a lot more for transmission.

It started with Enron, which bankrupted (or nearly so) California utilities, and then PG&E killed a lot of people and convinced the PUC to let them raise the transmission rates through the roof.

This chart doesn't copy and paste well, but as you can see generation is just 14 cents winter peak, 11 cents winter night -- but I pay 43 cents and 25 cents, so 2/3rds of the peak cost and almost half the night cost is not generation. Solar gives power at all those times but no distribution cost.

Summer Usage $0.55950 $0.44901 $0.24699
Winter Usage $0.43239 $0.41569 $0.24699 
Energy Rates by Component ($ per kWh) PEAK PART-PEAK OFF-PEAK
Summer Usage $0.19333 $0.14862 $0.10748
Winter Usage $0.13646 $0.12397 $0.10049
Summer Usage $0.26402 $0.19824 $0.03736
Winter Usage $0.19378 $0.18957 $0.04435
Transmission* (all usage) $0.04787 $0.04787 $0.04787
Transmission Rate Adjustments* (all usage) $0.00167 $0.00167 $0.00167
Reliability Services* (all usage) $0.00012 $0.00012 $0.00012
Public Purpose Programs (all usage) $0.02197 $0.02197 $0.02197
Nuclear Decommissioning (all usage) ($0.00013) ($0.00013) ($0.00013)
Competition Transition Charges (all usage) $0.00023 $0.00023 $0.00023
Energy Cost Recovery Amount (all usage) ($0.00429) ($0.00429) ($0.00429)
Wildfire Fund Charge (all usage) $0.00459 $0.00459 $0.00459
New System Generation Charge (all usage)** $0.00299 $0.00299 $0.00299
Wildfire Hardening Charge (all usage) $0.00141 $0.00141 $0.00141
Recovery Bond Charge (all usage) $0.01112 (I) $0.01112 (I) $0.01112 (I)
Recovery Bond Credit (all usage) ($0.01112) (R) ($0.01112) (R) ($0.01112) (R)
Bundled Power Charge Indifference Adjustment
(all usage)****
$0.02572 $0.02572 $0.02572 

The grid is not green.

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