Solar Power

You've probably held a solar cell in your hand. Calculators and watches are now commonly powered by small solar cells, so as long as there's light around, they work. For free.

But what about larger applications, like your house? Well, that's where a solar panel comes in. A solar panel or module is actually constructed of a whole bunch of solar, or photovoltaic, cells connected together and placed into a frame for ease of transportation and installation.

While solar panels are not exactly cheap-a panel that generates over 150 watts will run you over $700-they have no moving parts, require very little maintenance other than making sure dirt and debris are occasionally removed, and last decades. So figure $800 over 20 years, that's just a hair over $3 per month!

We're now used to seeing solar panels strung together in an array, and usually mounted on the south-facing side of an angled roof. More and more businesses with flat roofs are installing arrays of panels as well. And in remote locations or for those who do not have a south-facing area on their roof, a free standing solar array can be constructed with the advantage that it can be programmed to track the sun for maximum energy generation.

Each panel produces a set amount of electricity when exposed to full sunlight. However, several factors can reduce the amount of energy generated, like partial shade, natural debris like leaves and pine needles, and heat.

Yes, heat. Solar panels work well in full sun, but they lose efficiency as the temperature rises. The highest efficiencies are achieved in areas with lots of sunlight during the summer, but a reasonable ambient air temperature. In August, a solar array in Seattle will probably function more efficiently than one in Phoenix.

When considering placement of solar panels, remember that you may have a reasonably clear view of the sky, but that neighbors' trees or other objects may cast shadows on your property. It's a good idea to examine the area where you plan to place your solar array at different times of the year and different times of the day.

But solar "panels" now come in an ever-expanding array of shapes, sizes and flexibilities. One of the most exciting innovations are panels that look like standard tabbed roofing shingles, and install in the same manner. You just make a simple electrical connection after placing the row of shingles! You'll see flexible solar panels attached to sailboats, RVs and campers, even backpacks.

Solar panels are becoming more efficient even as prices drop. And the cost of fossil-fuel energy will not go down. Those two factors alone would make the purchase of one or more solar panels a great investment, even without the benefits of renewable energy and zero air pollution.