Interesting, does that factor in the cost of a roof and replacement panels at the end of the roof's life? IIRC they last 10-15 years tops down there. I did the math here and I won't live long enough to see any real savings. FTR I am not being confrontational.
The roof is relatively new (concrete tile). So, this is just the installation cost, which includes removal of the inoperative pool solar hot water panels (which no longer work, and have been replaced with propane). 25 year guarantee on parts and installation. So that ROI continues after it is paid off, and as you say, I may not be here for them to age out. I don’t expect electric rates to be considerably lower 25 years from now (unless we can replace the standby generator with a “Mr. Fusion”), so the future owner of this house will likely have to consider the cost of replacement and cost of power for their needs.
It does assume net metering, which is true now. Part of the impetus (in addition to whopping power bills here, due to the features of the house) is to lock in that net metering deal. The ROI shifts considerably if I am not able to sell excess daytime power back at the same rate as I buy it. The purchase of batteries (like the Tesla Powerwall) would add considerably to the cost, and change the calculus quite considerably. The batteries would be more attractive if I didn’t have the 24kW Generac for standby power. Neighbors tell me that we almost never lose power (and the lines are underground) but I still want backup generation for a variety of reasons - AC in the summer, future needs, interior lights, pool pump and filtration, etc. If we didn’t already have the Generac, I would have considered multiple batteries to fill that back-up requirement.
Again, I am running the numbers based on a steady 18c/kWh, and if the cost of power goes up, then everything solar pays for itself more rapidly.
Here are my rough numbers - April power bill $450. May is shaping up to be $550. I anticipate Summer to be around $650-700. Total solar installation is $56,000, all in, for a 28 kW system, which will exceed our peak daytime use in the summer - with AC, vehicle charging, everything. The current trade situation has driven the cost of solar up, but this is the quote today, and there are no more Federal, or even state, tax incentives available to us for the installation.
Without those incentives, it still makes sense. I’m not being “pushed” by any externalities, this is a pure cost consideration.
The amount of insolation varies over the year, and we are mostly south facing with the installation, but the system should generate more than we use most months, with a few winter months being slightly below our average daily use. With net metering, I should be about zero net use for the year.
Company risk is a consideration, that is, how likely is the company to exist 25 years from now? I interviewed/talked with 5 different companies. Picked a local one that has been in business 20 years. That’s no small consideration. They use German made panels and US made inverters. Parts quality is an important consideration, too.
Solar made no sense for us in Virginia Beach - no tax incentives at the state level, much lower power use, lower insolation, an east/west orientation on the roof and a short time horizon for the ROI.
But here? In the new house? Can’t wait to get it installed.
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