Humanity has acknowledged the power of the sun since prehistoric times, awed by the glowing orb whose presence creates day and whose absence plunges the world into darkness.
For all our advances in science and technology, most of the power from the sun still eludes us. NASA reports that we use only one ten-thousandth of the sun’s energy.
Photovoltaic (PV) solar electrical systems offer new and ever-changing ways to harness that energy. The term “photovoltaic” literally means light-electricity.
In 1839, French physicist Edmond Becquerel discovered that sunlight could produce an electric current. Another century would pass before scientists fully understood that this process happens at the atomic level. Albert Einstein’s only Nobel Prize was awarded for his work on the photoelectric effect. By 1958, the space program was using solar cells.
The most basic elements of PV systems are solar cells consisting of semiconductor materials. These materials absorb sunlight, and the solar energy in the sunlight zaps electrons loose from their atoms. Circuits built into the cells convert the electrons into electrical current. Solar cells are interconnected to form modules and panels. Place enough panels on your roof, or on a ground-mounted system, and your home can be freed from a reliance on conventional electrical energy.
According to the U.S. Energy Information Administration (EIA), the average monthly electricity consumption for residential use is about 908 kilowatt hours per month. Since residential solar energy systems are modular, the size of your system is up to you. A small system will offset the costs of running your most power-hungry appliances. A larger system can power your entire home.
Energy derived from fossil fuel is unsustainable. In 2000, conventional power stations accounted for 21.3 percent of the world’s greenhouse gas emissions, according to the Emission Database for Global Atmospheric Research. While solar power’s potential for solving global energy needs is profound, reducing the effects of climate change is just one of the advantages of solar energy.
How Efficient are Home Solar Panels?
Costs for traditional electricity have doubled in most areas since 1999. According to the EIA, global energy consumption is expected to double by 2035, and costs for that energy are expected to double as well. Electrical energy produced from PV systems is virtually immune to cost variations.
Continuous technological innovations are making solar panels more efficient and less expensive to produce. Solar innovators are increasing efficiency by altering the materials and technologies used in the components, such as using lining materials that help panels to absorb more light. Only a few years ago, a 12% efficiency rate was considered optimum.
Today, an 18% efficiency rate is not uncommon. The cost of manufacturing PV system components is plummeting, with module prices falling 12% over the last year.
Solar Costs, Rebates and Incentives
A wide array of solar rebate, tax credit and other incentive programs are available that can reduce installation costs up to 75 percent. The federal incentive program alone offers up to 30 percent off the cost of installation. Depending on where you live, programs offered at the state and local level can be nearly as generous.
Most utility companies meet mandates that require them to invest in renewable energy by offering their own incentive programs, including rebates and financing options, and by buying back any excess energy produced by residential systems.
A variety of financing options are now available, too, from home loans offered through solar companies, utilities and financial organizations, to leases. Leasing lets homeowners install PV systems with no money down, and the payments are typically less than was being paid on monthly electrical bills.