The importance of testing and measuringsolarmodules for quality and reliability was a common thread through three keynote speeches about solar's past, present, and future that kicked off the 39th IEEE Photovoltaic Specialists Conference in Tampa, Florida.
“The past few years have felt like a whirlwind, but they have been evolutionary changes,” GTM Research VP Shayle Kann told an audience comprised mostly of young electrical engineers. “But it is the cusp of a brand new market.”
Kann separated solar’s recent years into three episodes: the 2004 to 2009 period when technological advances drove module prices slightly downward; the 2009 to 2010 period when manufacturing undercapacity and a silicon shortage drove prices up; and the post-2010 years when overcapacity and technology advances have driven module prices down to the $0.60 to $0.70 per watt range.
Prices may have stabilized, Kann said, thanks to a margin erosion of 20 percent or more and the collapse of more than 100 manufacturers. Though opportunities for innovation may have been lost, Kann added, there is now significant potential for companies to succeed in sustainable markets.
The U.S. share of the global market continues to grow and should be 15 percent to 16 percent by 2016, Kann said, making the U.S. one of the world’s three leaders.
Two coming changes are going to turn solar’s evolution to revolution, Kann concluded. Socket parity, already achieved in California and some other markets, will free solar from the need for any subsidy but the federal investment tax credit, which will be available until 2016. In addition, new investment opportunities will allow many more people to buy in to solar include zero-down programs for homeowners, crowd-sourced and community solar programs for non-homeowners, and REITs, securitization and MLPs for investors.
Together, these things will create a “distributed solar revolution,” Kann said, predicting U.S. solar installed capacity will reach 18 gigawatts by 2016. But Kann named two areas of concern that could impede solar's progress. Calling utilities’ attempts to undo net metering one of solar’s “most crucial current battles,” Kann said such resistance could impede solar growth in the near term. Or, he added, utilities could avoid what a recent Edison Electric Institute paper called “a death spiral” by dropping their obstruction and buying in. Second, Kann contended that the industry must deal with concerns about module reliability by establishing quality standards before solar's public reputation sours.
Department of Energy Program Director Dr. Howard Branz followed with a rundown of the ARPA-E program. It was proposed in 2007 and funded in 2009, Branz said, to reduce greenhouse gas emissions and energy imports and increase energy efficiency in the U.S. by removing “high-risk technical barriers.”
To date, ARPA-E has invested $770 million into 285 transformational and disruptive technology research projects that could lead to “new learning curves.” The program has not produced any home runs yet, Branz said, but some are rounding second base.
Despite being a government program, Branz added, it has taken ideas from engagement and evaluation to established research projects in six months to nine months. To do that, the program makes its standards, procedures and metrics clear, Branz stressed.
Among ARPA-E’s ongoing projects are:
- Direct wafer research to bring silicon technologies to higher efficiencies
- Flow battery projects aimed at making energy storage affordable enough to create short-term disruptions
- Better rechargeable alkaline batteries
- Increased efficiency high-power circuit components that will help interconnect PV with the grid by managing power flows
- A bidirectional 120-kilowatt solar inverter
- Lattice-matched, triple-junction, 50-percent-efficient solar cells
- Optical techniques to create ultra-high efficiency solar by capturing more light for conversion to electricity
Some of ARPA-E's newest programs include research into light-reactive fluids that change the way CSP works, efficiency improvements for organic PV, and the development of a radiative cooler.
“We fund high-risk stuff,” Branz said. “We know most of it will fail. We are more focused on what is needed than on what people think they can do.”
The session concluded with IEEE’s Cherry Award-winning researcher Keith Emery running through lessons gleaned from his four decades of work on module standardization and quality.
Emery was among the 60 engineers and scientists at the 1975-76 NSA meetings that established working groups to define standard test conditions. During the 1980s, he said, the world community joined the effort to begin robust international and domestic standards development.
Running through a list of a dozen topics and areas, Emery said many remain ongoing issues, including:
- The cell area to test
- The PV module area to test
- The area of a silicon wafer on which to place contacts during testing
- Uncertainty analysis
- The standardization and independent validation of test software
- Quantum efficiency measurement in the evaluation of CPV technologies
- The adequacy of test equipment in measuring the efficiency of multi-junction cells
- The evaluation of bifacial PV modules
- The evaluation of indoor PV applications
The unit of watts-peak is “here to stay,” Emery said. But as he ran down that list of unresolved test and measurement issues, Kann’s earlier warning about the need to establish and maintain quality standards echoed through Emery’s repeated refrain of “Nobody knows about that.”