China has bet on solar energy as a cleaner alternative to coal, but whether installed solar panels can meet the country's need for energy is becoming a troubling question.

China had installed nearly 19.5 gigawatts of solar panels as of the end of 2013. However, "many solar installations failed to generate as much electricity as planned," said Ji Zhenshuang, deputy director at the Beijing-based China General Certification Center, which examined 472 Chinese solar projects over the past four years.

Ji would not specify the percentage but said the figure is not small. The solar projects his company examined include those under Golden Sun, a government-led program that was introduced in 2009 to demonstrate the use of solar energy, as well as utility-scale solar farms run by Chinese energy giants.

Although China in recent years has surpassed many countries in adopting solar technology, in a move to help Chinese factories survive tougher export markets and to cut the country's dangerous reliance on coal, there is little public information available on how well the Chinese solar projects function. However, some experts did not seem surprised by Ji's findings.

"[The performance issue] definitely exists," said Lin Boqiang, director of the China Center for Energy Economics Research at Xiamen University. "Since so many solar panels were produced here in such a short time, it is hard to imagine that there is no quality problem."

According to government statistics, the Chinese solar industry, which barely existed a decade ago, exploded to reach a production capacity of 26 GW in 2013, manufacturing more solar panels than the rest of the world combined. Lin said the rapid industry expansion brought in unqualified solar panel makers, and when companies raced to cut costs, substandard materials found their way into the supply chain.

Meteoric rise and then failures
Ji of the China General Certification Center said defective solar panels are a cause of the poor performance in the inspected solar projects, but hardly the only one. His inspection showed that other factors, such as cloudy weather, improper installation and difficulties in hooking solar panels up with power grids, have also played a role.

"Grid constraint is still an issue in western China. Sometimes solar farms are forced to shut down because power grids there are unable to carry the generated electricity. This on-and-off operation ruins solar systems in a similar way as frequent start-and-stop does to a car brake," Ji said.

Speaking at an industry conference last week, Wang Sicheng, a senior researcher at the Energy Research Institute of China's National Development and Reform Commission, told reporters that lower-than-expected power outputs in existing Chinese solar projects have already become an issue that holds back the sector's development.

Local newspaper 21st Century Business Herald cited Wang as saying Chinese banks are hesitant to finance new solar projects because of concerns over poor performance. To remove this barrier, Wang said, the government will issue a guideline next month to help developers assess solar product quality and improve project design, operation and maintenance.

But doubts remain about how effective this guideline would be. "The question is no one knows what kind of products or designs can last through 25-year operation. We haven't seen enough solid information from the field," Ji said.

He added that an overly ambitious quality control goal could put China at risk of building solar farms with unnecessarily high costs. But he insisted that the ongoing performance problem and the challenge of overcoming it are part of the learning curve, saying the nation will figure out a way to better manage its solar projects, with on-the-ground data-collecting work being a step in the right direction.

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC., 202-628-6500