by St. Funogas, Survival Blog:
Author’s Introductory Note: Grid-tied solar panel payback time is less than seven years in most of the lower 48 states, and quickest in some of the New England states, so don’t think solar isn’t for you just because you live in North Dakota or Vermont. RUN THE NUMBERS which I’ll show you how to easily do. If you don’t care about all the details of how and why, skip to the last section called “Quick Way to Figure out Payback Time.” There are only three numbers to enter on your calculator and you’ll have your payback time in years. Then you can come back and read the details if you’re so inclined.
From time to time on SurvivalBlog discussions come up about whether or not solar panels can pay for themselves. I’ve been amazed as I’ve traveled around the country and seen so few homes with solar panels, and wondered why more people don’t take advantage of nearly-free electricity. I’ve concluded that the three biggest reasons are 1.) most people are not aware of how simple it is to install grid-tied solar panels yourself, 2.) they erroneously think they need storage batteries and all kinds of complicated equipment, and 3.) they’re not sure how to do the math to figure out if solar panels are feasible in their area.
FIRST, A BRIEF TUTORIAL
So, let’s tackle those reasons in a quick tutorial.
First, if you can hook up an electric water heater, you can most likely hook up your own grid-tied PV system in a couple of days. Second, if you can install them yourself and follow some basic rules of frugality outlined below, nearly everybody in the lower 48 can make a home, grid-tied PV (photovoltaic) system pay for itself in 3½ to 7 years.
My philosophy behind having a grid-tied PV system is this: for now, we want inexpensive electricity and something simple to get us started in solar energy and, in the event of TEOTWAWKI, we want to be able to have the ability to convert our system over to something that will at least charge some batteries to provide lighting for our post-SHTF life, and hopefully much more than that. We are not trying to save the planet so let’s avoid that topic in the comments section please. (Note on EMP/Carrington Event later.)
WHAT IS A GRID-TIED PV SYSTEM?
Since there are no batteries involved, a grid-tied PV system is a very simple, maintenance-free setup. Instead of your solar panels charging a bank of storage batteries, the grid acts as your storage device. During the day when you are creating more electricity than you can use, your excess power goes out to the grid for your neighbors to use. At night, you borrow electricity back from the grid to run your home.
There are just two components: your set of solar panels and a small box the size of a desktop computer called an inverter. Three wires from the solar panels plug into the inverter, and, just like an electric water heater, four wires from the inverter hook into a double breaker in your home’s electrical panel.
I won’t go into the details of mounting solar panels since there are plenty of books and articles on that subject. The most crucial point to keep in mind is that, in most cases, the only way to make your PV system pay for itself in a reasonable amount of time is to do your own installation, or get it done “free” somehow via barter or bribing friends or relatives. The installation is not difficult. The second point to keep in mind is that you can make your PV system pay for itself much more quickly by making your own mounting rails rather than purchasing expensive ones offered by solar suppliers. I made mine from synthetic deck boards available at any lumber yard. You can probably come up with an even less expensive method.
THE PARTS LIST
I will be mentioning certain products but these are not endorsements. I have not kept up with technology since my installation, nor done any price comparing on inverters for this exercise. The point is to show that if I were rebuilding my system today, here’s exactly how I could do it, and at what price. If I were doing this for real, I would be doing more in-depth research and would undoubtedly find an even least expensive way to do it. So this is not a how-to article on setting up your home PV system, rather, a how-to article on determining the payback time on your investment with some pointers on frugality.
Here are some of the major expenses:
For our exercise, let’s install a 3,000-watt system on your property. That’s 10 solar panels which, when mounted in two rows of five, take up about 16’ x 11’. They can be either roof or ground mounted. The lowest average price now is 65¢/watt from several suppliers for 300-watt solar panels. 65¢ x 300 watts = $195 per solar panel. (A year ago I was seeing them as low as 61¢/watt at Home Depot.) Ten of those will cost $1,950 plus tax and shipping. I received an estimate of $400 on shipping so if you can buy locally, you’ll save considerably.
I used synthetic deck boards for the mounting rails but there are many ways you can approach this.
We’re going to need different kinds of hardware variously known as “fasteners.” Based on what I spent, $200 will more than cover fasteners, plus another $60 for conduit, wire, and mounting the inverter.
For the inverter, let’s be frugal and buy a brand-new SunnyBoy 3,000-watt inverter off eBay for $640 which includes shipping. This one lacks the “secure power supply” which gives you some power even if the grid goes down temporarily. But at $1,200 extra, there are much less expensive and more reliable ways to get power during an outage.
With tax and other miscellaneous, the total installation cost comes to $3,903. If you’re paying taxes to Uncle Sam in 2020 then you qualify for the 26% rebate which lowers your cost to $2,888 if you begin installation this year. (Next year it drops to 22%, then disappears in 2022.) That total is for my location where the local government minds their own business. If you need permits and are required to do other hoop-jumping exercises, add those costs to your total.
HOW MUCH ELECTRICITY CAN I MAKE?
Now that you know the cost to install 3,000 watts of solar panels, the next question is, how much electricity can I generate? Once we can answer that, we’re just one step away from knowing how quickly your solar panels will pay for themselves.
How much electricity your solar panels will generate is dependent on a variety of factors, the most important being your geographic location. In order to maximize your output, you’ll want to mount your solar panels in the sunniest location available, facing as due south as possible, and mounted at an angle that matches as closely as possible the degrees of your latitude. But everything doesn’t need to be “perfect” so just get as close as you can on these.