Renewable energy generates clean power, and the fuel is often free: There’s no cost to make the wind blow or the sun shine. But just as many people advocate for considering the full cost of fossil fuels in the price of electricity (the cost of the pollution, mining, etc), so too must the full cost and impact of renewable energy be accounted for.

A new life-cycle assessment study from the Brookhaven National Laboratory in New York examined the four most common types of photovoltaic (PV) solar power cells — multicrystalline silicon, monocrystalline silicon, ribbon silicon and thin-film, if you were wondering — to find out how much energy and waste was involved in their creation.

“Emissions from Photovoltaic Life Cycles” found that even when accounting for the metals required to build PV cells, the efficiency of the cells, and the waste produced, PV cells still emit less global warming pollution throughout their life cycle than the fossil fuels needed to produce the same amount of power. Actually, most of the pollution from the solar power comes from the indirect emissions of the fossil fuels used to generate the electricity of the PV manufacturing facilities.

>> Want cheap solar? Join the most effective community solar purchasing program in the US.

The most energy-intensive type of PV cell to make — the monocrystalline silicate cells — only emits 1.8 ounces of global warming pollution per kilowatt hour, compared to 2.2 pounds by a coal-fired power plant. All told, the construction and use of PV power would cut air pollution about 90 percent if it replaced fossil fuels.

The best-case scenario, of course, would be for solar manufacturing facilities to be powered by solar. Researchers concluded that 30 percent of the energy used to make PV cells could come from solar power installed on the roofs and parking lot of facilities.

While some people point out that the study only partly takes into consideration the transportation of PV components (most of which are made in China), the researchers want to broaden their work further to include end-of-life and recycling data of the PV cells. They believe this expansion could further improve overall emissions calculations.

Nanowerk

Scientific American

Treehugger