THE world’s biggest solar power company said a shortage of glass is raising costs and delaying production of new panels, throwing a wrench into China’s plans to accelerate its shift to clean power.

Prices for glass that coats photovoltaic panels have risen 71 percent since July, and manufacturers are struggling to produce it fast enough to keep more than a week’s worth of sales in inventory, said Daiwa Capital Markets. The shortage comes as the solar industry turns toward bifacial panels, which increase both power output and glass requirements.

Solar panel producers like Longi Green Energy Technology Co. have asked the government in China, home to most solar manufacturing, to address the situation by approving new factories. Otherwise, price hikes risk making solar power too expensive and halting the industry’s momentum.

“If solar power generators see solar projects as uneconomical, they will delay investing in new projects and that will drag down solar demand,” said Charles Jiang, head the supply chain management center at Longi, the world’s biggest solar company by market capitalization. “Solar power plant profits will drop below acceptable levels without government subsidies if glass makers go on to push up the costs.”

In 2018, with the energy intensive and polluting glass industry facing over-capacity issues, China’s government forbade companies from adding new production capacity. Longi and five other major solar companies Tuesday met with government officials and appealed for them to remove the restrictions, at least for solar glass.

Glass demand has also been rising within the solar industry because of the increasing prominence of bifacial panels, which coat both the top and bottom with glass, allowing for a slight uptick in power generation from sunlight reflected off the ground. Such panels are expected to make up half the market in 2022, up from about 14 percent last year, according to analysts at Sunwah Kingsway. (SD-Agencies)