Solar Industry Now a Net Energy Producer
April 4, 2013
As the solar industry continues explosive growth, you can bet the pushback from fossil fuel interests will increase. Trust me on this, you’ll be hearing about “solar cell syndrome” soon.
One of the more superficially credible snarks you might have heard in recent years would be the one about how much energy or rare materials go into producing solar panels. As the concerns about costly materials are steadily being addressed by new technology, new research at Stanford indicates that the obvious is now occurring – solar is becoming a net producer of energy, and going forward, more and more of the energy produced is “extra” energy that will be used for economic activity and to provide services.
The rapid growth of the solar power industry over the past decade may have exacerbated the global warming situation it was meant to soothe, simply because most of the energy used to manufacture the millions of solar panels came from burning fossil fuels. That irony, according to Stanford University researchers, is coming to an end.
For the first time since the boom started, the electricity generated by all the world’s installed solar photovoltaic (PV) panels last year probably surpassed the amount of energy going into fabricating more modules, according to Michael Dale, a postdoctoral fellow at Stanford’s Global Climate & Energy Project (GCEP). With continued technological advances, the global PV industry is poised to pay off its debt of energy as early as 2015, and no later than 2020.
“This analysis shows that the industry is making positive strides,” said Dale, who developed a novel way of assessing the industry’s progress globally in a study published in the current edition of Environmental Science & Technology. “Despite its fantastically fast growth rate, PV is producing – or just about to start producing – a net energy benefit to society.”
The achievement is largely due to steadily declining energy inputs required to manufacture and install PV systems, according to co-author Sally Benson, GCEP’s director. The new study, Benson said, indicates that the amount of energy going into the industry should continue to decline, while the issue remains an important focus of research.
“GCEP is focused on developing game-changing energy technologies that can be deployed broadly. If we can continue to drive down the energy inputs, we will derive greater benefits from PV,” she said. “Developing new technologies with lower energy requirements will allow us to grow the industry at a faster rate.”
The energy used to produce solar panels is intense. The first step in producing the silicon at the heart of most panels is to melt silica rock at 3,000 degrees Fahrenheit using electricity, commonly from coal-fired power plants.
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 feed stock, 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.
To be considered a success – or simply a positive energy technology – PV panels must ultimately pay back all the energy that went into them, said Dale. The PV industry ran an energy deficit from 2000 to now, consuming 75 percent more energy than it produced just five years ago. The researchers the industry to pay off this energy debt as early as 2015, thanks to declining energy inputs, more durable panels and more efficient conversion of sunlight into electricity.