Ever get the feeling that if you went outdoors and looked at your electric meter, the numbers would be spinning right before your eyes? Electric rates may not be rising as fast as oil or gas rates, but wouldn’t it be nice if we could heat our homes and run our appliances for free? That’s asking a little too much, of course, but there are alternate sources of energy: wind, water, geothermal, and solar, to name just a few. So what will it cost you to change your house over to solar?
Passive vs. Active
There are two kinds of solar energy systems: passive and active. Passive solar uses techniques that are dependent on the characteristics of your home: windows, walls, floors, roof, basement, as well as landscaping and exterior design. Depending on where you live (hot vs. cold climate) all of these elements are used to either maximize or minimize the heat generated by the sun. Large, south-facing windows that allow the sun’s heat to pour in and be absorbed by a dark stone flooring system is a good example of passive solar. The use of shade trees and reflective windows on the sunny side of your home is an example of passive solar ideas to prevent overheating.
Active solar power refers to a process that converts sunlight into electricity by means of some sort of mechanical device, namely a photovoltaic (PV) system. Most PV systems these days are based on silicon, an element found all over the world in great supply. There are various ways of processing the silicon to create photovoltaic cells which are the building blocks for those familiar solar panels we see on roofs all over the country these days (see below). When sunlight hits these panels, silicon electrons within the cells break free and create an electric current.
The possibility exists for materials other than silicon to be used to create solar energy, and research is currently underway, but for now, silicon is the way to go.
How A Solar Energy System Works
Many interconnected PV cells form what is called a solar module, commonly known as a solar panel. A grouping of solar modules is called a solar or photovoltaic array. The size of the PV array depends on how much power you want your system to produce. In general, modules can produce anywhere from 10 to 300 watts of direct-current (DC) electricity. The electricity that is used in our homes is alternating current (AC), so an inverter is needed to convert the energy from DC to AC.