BEIJING—The Biden administration’s solar power ambitions are colliding with complaints the global industry depends on Chinese raw materials that might be produced by forced labor. A big hurdle is polysilicon, used to make photovoltaic cells for solar panels. The global industry gets 45 percent of its supply from Xinjiang, the northwestern region where the ruling Communist Party is accused of mass incarceration of minorities and other abuses. Other parts of China supply 35 percent. Only 20 percent comes from U.S. and other producers. Biden’s climate envoy, John Kerry, says Washington is deciding whether to keep solar products from Xinjiang out of U.S. markets. That sets up a conflict with President Joe Biden’s plans to cut climate-changing carbon emissions by promoting solar and other renewable energy while also reducing costs. In Xinjiang, more than 1 million Uyghurs and other members of predominantly Muslim ethnic groups have been forced into detention camps, …