Thanks largely to increasingly efficient materials and manufacturing processes, the solar PV that was installed globally during 2012 likely produced more energy than was expended to make panels during the year. And now that it’s operating in positive territory on an annual basis, Stanford researchers say, by perhaps as soon as 2015, the industry could break into the black on a lifetime basis.
“This analysis shows that the industry is making positive strides,” Stanford’s Michael Dale, co-author of a new study published in Environmental Science & Technology, said in a statement. “Despite its fantastically fast growth rate, PV is producing -- or just about to start producing -- a net energy benefit to society.”
According to Dale and his Stanford Global Climate & Energy Project co-author Sally Benson, the industry had run at an energy deficit during its boom years since 2000 -- and in the process was producing more greenhouse gas emissions than it was saving, due to a couple of factors.
First, the panels that produced clean energy for a generation or more were being churned out at a rate that was growing meteorically. And second, it took an enormous amount of energy -- energy, like any that comes off the grid, that mostly came from burning fossil fuels -- to make the panels. (For a close look at the PV manufacturing process, see our report and video from the SolarWorld plant in Hillsboro, Ore.)
But things are changing. According to the Stanford release about the study:
"As investment and technological development have risen sharply with the number of installed panels, the energetic costs of new PV modules have declined. Thinner silicon wafers are now used to make solar cells, less highly refined materials are now used as the silicon feedstock, and less of the costly material is lost in the manufacturing process. Increasingly, the efficiency of solar cells using thin-film technologies that rely on earth-abundant materials such as copper, zinc, tin and carbon have the potential for even greater improvements."
The Stanford researchers said continued vigilance on the energy-cost side -- not just the financial cost of making and installing panels -- will be necessary to continue the positive trend, but at current rates the gap between energy used and produced should widen.
One especially interesting point the researchers made concerned the impact of where panels are installed on the input-output equation. Germany is celebrated for its world-leading commitment to solar, but in some ways that might not be the most efficient deployment of solar.
“At the moment, Germany makes up about 40 percent of the installed market, but sunshine in Germany isn’t that great,” Dale said. “So from a system perspective, it may be better to deploy PV systems where there is more sunshine.”