Covering large parking lots with solar panels is an idea that goes back decades but in America at least it’s an idea that has never really taken off.
What is the reason for that? Is it due to the overall cost or is there something else that keeps Walmart, Target, Costco, Sams Club, Malls, etc. from covering their parking lots with these panels and selling the power?
There are some parking lots like that around here, though not many. Obviously expense is a large part of it. Photovoltaics get cheaper all the time, but there is all the other gear (inverters, transmission lines), plus the construction costs. Web search for solar parking lot or solar canopy finds a fair amount of data.
I do think solar off-grid is now economically feasible for a modest home. It’s easier for a DIY homeowner than for a commercial operator to control costs by scrounging.
Wouldn’t all of those costs be offset by the power generated? At least, the solar power would reduce the stores’ draw from the grid. At most (depending on the size of the parking lot) the store would feed the grid on sunny days.
It seems to me that investing in the panel canopies, controllers, and modified grid connection would soon pay for itself and then fund the installation of the same for the next store.
If there was truly money to be made, people would be making it. Never underestimate the dedication of opportunists.
So if it’s not happening, it’s because the dollars aren’t there.
Second question should be, why aren’t the dollars there? Is it artificial limitations, like laws about power generation? Is it the cost of the supplies only? We understand that, we can fix the problem.
You have to do the math. That solar canopy ends up costing around $5 per watt to install, apparently. WIth 0.3 solar constant (counting some other factors) that’s 2.6 KWH/year per watt of solar, maybe 30 cents at industrial rates. So 15-ish years to pay off. Of course you can change the parameters around and do the math differently. Also hmm, 5% interest on the $5 is $.25 so that kills most of the 30 cents you get back in electricity. Scale this up to a 1 megawatt ($5 million) array for a Walmart sized parking lot and it’s not so attractive. It was better a few years ago when interest rates were near zero.
There’s also leverage to make a bulk deal for the panels and installation because it’s Walmart or whatever, rising cost of electricity (depending on location) shortening the payoff time, grants and tax breaks for renewable energy, the value of a green energy initiative for a PR push, attracting more customers because their cars can park in the shade.
If they have to design custom canopies, wiring solutions, etc, it would add to the costs a lot.