By Kim Robson
My neighborhood in the mountains, Cuyamaca Woods, is completely off the grid, and residents here all rely on solar electricity. When my husband and I fell in love with this area, we knew we’d have to learn about photovoltaic (PV) systems.
Going solar doesn’t have to be a budget-breaker. With only four solar panels, eight batteries, and one small backup generator for winter days, all of our electric needs are easily met. Solar panels cost about $550 each. The inverter/charge controller is about $2000. A small generator was $1800. And batteries run about $80 each. People living completely off the electrical grid need some additional components for their PV system: a charge controller manages the amount of energy being used to charge storage batteries for nighttime; an inverter converts the DC charge to AC so it can run the house; and a backup generator is a good idea for periods without sun. Add in wiring, connectors, etc., and we were up and running for around seven grand. Our utility savings amounts to 100%.
Most people, however, do live on the electrical grid, and people can’t easily be disconnected from it. In that case one would install a “grid-tie” system with which solar energy powers the home; but if solar alone isn’t enough to meet the family’s energy needs, then the electric utility would kick in to make up the difference. Conversely, if the system produces more electricity than your household can use and your utility company offers “net-metering,” excess energy flows back into the main grid, and the owner can get paid for the extra electricity.
PV systems should be installed by a licensed electrician with experience in solar systems. (Maintenance after installation is minimal.) The cost of solar power can vary, depending on your climate, your energy needs, and existing utility rates in your area. In 2009, the cost of a residential system averaged between $8 and $10 per watt (source: National Renewable Energy Laboratory). Many opportunities to defray up-front and installation costs exist in the form of federal and state tax incentives, utility company rebates, and other financing opportunities. The federal rebate gives back a whopping 30% of the installed price of solar panels and solar water heaters, with no maximum. California state rebates vary between $2.50 and $4.00 per watt. Many utility companies offer their own additional rebate programs. Installing a PV system in your home can add significantly to its market value, and you may also qualify for property tax exemptions.
Even if you don’t own a home, there are many ingenious ways to harness solar energy. Web resources show how to lease solar panels for short-term use with no up-front costs, or how to use solar power in an apartment with panels you can mount outside a window. In fact, more and more low-income housing is built now with PV arrays on the roof and fuel cells in the parking lot. Greenhouses can remain warm during winter or on dark days with heaters run on solar-charged
batteries. Solar charging stations for electronic devices are also common. Now, small PV units can recharge cell phones, tablets, laptops, batteries, MP3 players, or cameras. Climatically blessed cities in Europe and the U.S. are installing solar car-charging stations for electric vehicles.
The newest solar cell technologies are stretching the materials barrier. Thin-film solar cells can be made from a variety of materials, including amorphous silicon and many other elements. They are flexible, lightweight, and can be wrapped around amorphous shapes. While they also tend to sacrifice some efficiency, they’re simpler and cheaper to produce — and the technology becomes more efficient every year.
On an industrial scale, desert regions are concentrating solar energy with lenses and mirrors to focus light onto highly sensitive cells. Electricity produced there is then transported long-distance over high-tension DC lines to the cities where it’s most needed.
In the near future, we may see everyday items like PV-powered curtains, clothes, and laptop cases with invisible solar cells. Even the miniature world of nanoparticles is being explored, and researchers are beginning to explore the potential for organically produced solar cells. Ultimately, the goal is to consume fewer non-renewable resources, as going solar reduces our carbon footprint on an immediate, tangible scale. The sun is literally the limit!
Did You Know?
Electricity is hardly “clean.” In the U.S., about 45% of our electricity comes from coal-fired power plants; natural gas accounts for 24%; and nuclear energy powers 19% of U.S. households. Only six percent is generated by hydroelectricity. The remaining six percent comes from solar, wind, geothermal, or biomass sources. The handy calculator from the EPA can tell you, based on your zip code, where your electricity originates
The sun is a gigantic nuclear fusion reactor running on hydrogen fuel. It converts five million tons of matter into energy every second and sends this energy to Earth in the form of visible light and infrared radiation. Scientists expect that the sun will continue to provide light and heat energy for the next five billion years. Full sunlight produces about 100 watts of solar energy per square foot. If you assume 12 hours of sun per day, this equates to 438,000 watt-hours per square foot per year. Based on 27,878,400 square feet per square mile, sunlight bestows a whopping 12.2 trillion watt-hours per square mile per year. The amount of solar energy that strikes Earth’s surface every year is about 29,000 times greater than all of the energy used in the United States.
Powerful Rays of Light
By Kim Robson