In 2009, the average American home used 10,896 kilowatt-hours of electricity every year, according to data from the U.S. Energy Information Administration (EIA). The EIA also reports that the amount of carbon dioxide released to generate a single kilowatt-hour of electricity by a coal plant is just over 2 pounds, or about 23,000 pounds per year.
Over the 25- to 30-year lifespan of a full-scale residential solar system, about 575,000 to 700,000 pounds of carbon dioxide emissions will be offset.
Data released from the Environmental Protection Agency in 2000 found that the average car produces .916 pounds of carbon dioxide per mile, and drives an average of 12,500 miles each year, for total annual carbon dioxide emissions of 11,450 pounds.
If each home in the state of California were to convert to solar energy, the impact would be equivalent to taking 20 million cars off the road (for comparison, the state's total population is around 38 million).
Solar panels, of course, do not appear out of thin air, and the materials used to produce them, as well as the processes used to manufacture and transport them, can trigger environmental concerns.
A study conducted at Arizona State University examined the life-cycle emissions of solar panels. The study took into account both the production of the machinery needed to manufacture solar panels and the transportation used to deliver them on site.
The study showed that 32 grams of carbon dioxide were emitted for every kilowatt-hour of solar-generated electricity. Since the study's release a decade ago, technological and manufacturing advances have cut that figure in half. Compare 16 grams of carbon emissions per kilowatt-hour of solar energy to the 2 pounds per kilowatt-hour emitted by coal-powered energy, and you can spot a clear winner.
While solar panels are 90-percent glass, another ongoing concern is over other materials used in making solar panels. Some solar cells use toxic cadmium. Others use rare metals like indium. As the first wave of modern solar panels are reaching the end of their life-cycle, major industry players in the PV market are recycling their own products, including First Solar and Solar World. Other companies, such as PV Recycling in Tuscon, Arizona, are specializing in recycling PV components, converting aluminum frames into raw material, reclaiming silicon into new solar cell production and reusing glass.
Silicon Valley Toxics Coalition, a not-for-profit organization that monitors both the environmental effects and health effects of emerging technologies, recently released its Solar Scorecard, a ranking of global PV manufacturers based on a number of criteria, including the use of raw materials, chemicals used in production, waste and disposal policies, workplace safety and recycling. Thirteen of the 15 companies included in the study reported auditing and monitoring their supply chain for health, safety and environmental issues. Eleven said the would publicly support laws mandating recycling.
While some apprehension over environmental effects of the production, transportation and recycling of solar panels is valid, and should continue to be addressed, replacing harmful fossil-fuel electrical systems with green, solar energy exponentially outweighs those concerns.
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Hailing from Oakland, CA, Brittany Mauriss is editor for CalFinder, a free service that connects you with all-star solar contractors and remodeling pros. Her passions are music, sustainable building, and helping people make beautiful homes.
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