TOKYO (Nikkei)–Now that a law introducing feed-in tariffs for solar power has passed in the Diet, Japanese manufacturers of solar panels are working on a product certification system to ensure product quality.
The current system offers buyers little reassurance with regard to durability, which is a crucial factor in determining the cost effectiveness of solar power systems.
Makers of such systems stress their warrantees, which range from 10 to 25 years, in their sales pitches. But there is no consensus among manufacturers on the life span of solar panels. Some say they will work for 20 years, while others claim they can last more than 30 years. The industry is concerned about the conflicting information because establishing the durability of solar panels is key to its efforts to expand solar power.
Under the feed-in tariff law, utilities are required to buy electricity from solar power at above-market prices. That, and the length of time solar systems can keep the juice flowing, determine how much income owners can expect to receive.
The longer the better
Some manufacturers say solar power systems have a useful lifespan of more than 30 years. Solar cells made by Sharp Corp. (6753) and installed at the lighthouse on Ogamishima Island in Nagasaki Prefecture have shown remarkable longevity. The original cell modules installed at the lighthouse in 1966 were replaced with new ones in 1978 due to specification changes. The new modules kept working for 31 years, until they were replaced in 2009 due to additional changes in the specs, the company said.
Because solar cells have no moving parts, they have a low failure rate. How long solar systems function depends mainly on good maintenance of ancillary equipment such as the converters that change the direct current generated by solar cell modules into the alternating current that households use. Such converters last about 10 years. Regular maintenance is vital to keep solar power systems operating. They are susceptible to problems that can prevent them from working at top efficiency, such as bird droppings and shadows from trees.
Not so bright
As sales of solar panels grow, the National Consumer Affairs Center is handling more calls from consumers complaining about poor performance of solar power systems. Many say they get less income from sales of electricity than the companies that sold the products said they would. The center received 1,161 such calls between April and Aug. 29, up 45% from the previous year. One major problem is the lack of a system to guarantee product quality over, say, 20-30 years.
The International Electrotechnical Commission has set quality standards for solar panels that stipulate the output decline must be less than 5% when operating at 85 degrees Celsius and 85% humidity for 1,000 hours. But that covers only about six weeks of use.
To tackle the problem, the Japan Photovoltaic Energy Association has begun developing a system of quality checks for long-term use of solar panels. The association hopes to have the system in place when the feed-in tariff law comes into force next July.
A reliable system to ensure that solar panels have a long life span would help solar power shed its image as a clean but costly form of energy. Michio Kondo, director of the Research Center for Photovoltaic Technologies at the National Institute of Advanced Industrial Science and Technology puts the cost of solar power generation at 27 yen per kilowatt-hour, assuming a 20-year life span, much lower than the government’s estimate of 37-46 yen. The cost would fall by half if solar panels can be made to last 40 years, Kondo said.
–Translated from an article by Nikkei staff writers Shiroki Akira and Kentaro Ogura
Filed under: 5.Climate Change & Carbon