Who can use Solar Power?
Solar panels generate free power from the sun by converting sunlight to electricity with no moving parts, zero emissions, and no maintenance. The perfect situation for a Solar Power energy system is a small remote location where it is not practical or is too expensive to have regular utility company power connected. (what I like to simply call the ‘Grid’).
Classic examples of this would be small cabins or homes that are far from the grid and use only moderate amounts of power. It many cases it is possible to pay for the entire system for what the utility company would charge to run lines to your remote site.
Other typical examples would be remote monitoring equipment and installations such as cell towers and the like. However, this website is primarily focused on the small homeowner who wants energy independence and no electric bills.
There will be times when there is little or no sun and some kind of back-up power should be available. If for example in the dead of winter, it was overcast and snowing for 3 weeks, it would not be practical to have a battery bank large enough to last that long. Most battery banks are sized to last 3 to 5 days without recharging. Usually a small to mid-sized AC Generator is used to charge the batteries during these periods.
Also, a generator is needed for short periods to operate very large appliances. For example, in the winter I wait until I am already using the generator to give the batteries a boost before I run the vacumn cleaner. Since charging the batteries does not use all the power the generator is putting out, it makes sense to run large appliances at this time. Of course, in the summer this in not necessary as I usually have excess power.
If you are connected to normal Utility company power and just want to add some Free Sun Power electricity to reduce your electric bill and you do not need a independent system, it is possible that a Grid Tie inverter will suit your needs. With a Grid Tie inverter, whatever electricity that your solar panels produce will reduce the amount supplied by the power company, in effect lowering your bill. And, if you are producing more power than you are using, you can actually sell the excess back to the power company! For this setup a large battery bank to store the power for later use is not needed. Unless you have frequent power company outages, you will not need any batteries at all.
To make a independent Solar Power system really practical, you need to replace power hungry appliances with alternative sources of energy. For example, using an electric stove instead of a gas stove (natural or propane), triples or quadruples the size of the system required. That would make a $12,000 system closer to $40,000! Electric hot water heaters & definitely electric heating systems are also not practical to use. Usually, you should consider replacing anything that uses over 1500 watts.
In addition, conservation is always part of the equation. Simple things like turning off the light when you leave the room are far more important with solar power than if you are connected to the grid. Even so, being independent from the Utility company and having no electric bills except the cost of a little unleaded fuel for the generator makes conservation a small price to pay.
System size and cost
To get a general idea of what parts are needed for a Solar Power energy system click on System Overview. A minimum system will run around $5000 but for real service expect to pay closer to $10,000 to $15,000. Check out my Solar Home to see what $8000 can buy. I have all the conveniences of a 10 cubic foot refrigerator, a desktop computer with efficient LCD monitor, a 27 inch Energy Star compliant color TV, a 1200 watt microwave oven, and assorted other lights and devices.
Based on the various systems I’ve seen, some ball park numbers would be :
Single person home $8,000-$10,000
Two person home $12,000-$15,000
Family of 3 or 4 $18,000-$20,000
These price estimates would be for typical energy usage and include an AC Generator for back-up power and all the equipment necessary for a completely independent fully functional solar power system. You could skimp somewhat by using less automation and working your batteries harder which would reduces the cost of the system 15 or 20 percent but in the end, performance would suffer. The System Sizing Estimator will give you a fair idea of the number of solar panels and batteries you’ll need for a variety of configurations.
How long does it take for a Solar Energy System to pay for itself?
It has always struck me as odd that one of the first questions someone would ask me is: how long before the system has paid for itself? 5 years? 10 years? More? You really can’t compare it to being connected to the Utility company for a number of years. But, for the sake of argument, let’s say after 10 years, you would have paid utility bills equal to what your system cost. Does the utility company stop charging you after 10 years? No. So, really, you want to think in terms of the life of the system. Probably 25 to 30 years. Now, how much would you have paid the utility company during that entire time? And don’t forget about all the price increases. And how do you put a price on independence, self reliance, and your personal contribution to the environment? Incidentally, it is a complete myth that a solar panel will never produce as much energy over its useful life to equal the energy that it took to manufacture it. That’s just the electric company talking…