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.  Cont'd..