One thing that I have learned over the years from talking to homeowners, business owners and even apartment renters, is that they like the idea of using solar energy. They would use solar energy if given the choice. Regardless of their political viewpoint, social status or cultural background, nobody thinks that using the sun’s energy is a BAD idea! Of course “the devil is in the details,” as they say. For a lot of reasons, mostly economic, Americans don’t utilize much (if any) Photovoltaic (PV) solar to generate electricity in their daily lives. But if you wanted to use solar, would you even know where to start?
Deciding if your home is in a good location for solar is a big first step. “Is it even practical to consider solar at my home?” is the first question you need to answer. Okay, I’m assuming that there is SOME sunshine where you live. If you live in the deep forest and there is no direct sun, you probably aren’t a good candidate. If you live in a cave, you may need a longer wire. Most people, however, get some direct sun hitting their property for some portion of the day. Do you have enough sun to grow tomatoes? Then you have the potential to use solar PV to make electricity.
“But I don’t live in Arizona! Do I get ENOUGH sun?”
I love to ask people the question “does Northern Canada get more or less hours of sunlight in a year than Southern Mexico?” Of course, most people guess that Southern Mexico gets more. NOT TRUE, my friend! In fact, everywhere on earth gets the same number of hours of daylight. At the equator, the days are the same length all year round. Up north, the days are long in the summer and short in the winter, but it all adds up the same! So… it is a matter of quality, not quantity. Of course, you will make more power on a sunny day than a cloudy one, but even in notoriously cloudy areas like Washington State, solar is used quite successfully.
“Solar window…what the heck is that?”
The make or break factor for deciding on whether or not solar is viable is determining your “solar window.” The solar window for any location is the portion of the sky framed by the arc that the sun travels from the eastern to western horizon on the the longest and shortest days of the year. For someone living near the equator, their solar window is going to stay directly overhead. For someone who lives farther north, the solar widow will be to the south, and to the north for someone south of the equator. Confused yet? Let’s look at some pictures, shall we?
In the first photo, you see a tree-lined yard, looking south. Are all of those trees going to be in the way? One way to tell is to use a tool called a solar pathfinder. The pathfinder allows us to take a picture of the solar window and see how those trees, the shed and other things will affect our performance throughout the year. The second picture shows the pathfinder and it’s analysis. As you can see from the numbers, the solar window is obstructed in the morning and evening, especially during the winter months, but it looks okay in the middle of the day. Not as good as a wide open spot, but not terrible.
As you can see here, we can shoehorn a little solar array into a pretty small patch of sun. This array is on the roof of a Garden shed in a very shady neighborhood, but it still manages to offset a good amount of the homeowners monthly electric bill.
“Shh…ucks, my roof doesn’t face south!”
Again, not necessarily a problem. A solar array can be mounted as an awning on the side of the house, giving it the added benefit of providing shade to those south-facing windows in the summer. Or, it can be mounted on top of a pole in the yard in a nice, sunny clearing and connect to the house via an underground cable. The roof is not the only place for solar. In general it is less expensive to install solar on the roof than other options, but it has it’s disadvantages, too. Solar panels on the roof can be hard to reach to clean or maintain, and they have to be removed when you need to re-roof.
“I think I have a good spot, how can I be sure?”
If you have a wide open view to the south, no problem. If not, you can use a solar pathfinder or a number of other nifty tools and phone apps that are available to help you calculate the exact amount of efficiency loss that will be created by shading. You can also get a solar site assessment done by a professional. Depending on where you live, your utility provider may offer you a free assessment. Once you have found the right spot for your array, you can start planning with confidence!