It does not match the stock market in any locale in the US. Artificial externalities may make it do so (government incentives, exorbitant energy rates) in Canada, in which case ok great. But I think you’re probably doing your math wrong.

I’m guessing you’re not counting the fact that if you buy a stock for $100 you still have the $100 (you can sell the stock) but that’s not true of solar because it’s an asset whose value quickly goes to near $0 as the cost of uninstalling the panels is more than they are worth or nearly so. You’d have to be getting near 20% ROI annually for it to match the stock market in that time frame. A quick google shows that even the Canadians selling solar don’t claim that. You don’t even get that in California, where the panels produce a multiple of what yours will and all of the other factors (incentives, latitude, high energy prices and net metering, etc.) lean toward solar so I’m guessing you’re erring.

Easy to verify though: what was your install cost and how much is it saving you on energy bills?