JIUQUAN, China — On the edge of the Gobi Desert, the Jiuquan Wind Power Base stands as a symbol of China’s quest to dominate the world’s renewable energy market. With more than 7,000 turbines arranged in rows that stretch along the sandy horizon, it is one of the world’s largest wind farms, capable of generating enough electricity to power a small country.

But these days, the windmills loom like scarecrows, idle and inert. The wind howls outside, but many turbines in Jiuquan, a city of vast deserts and farms in the northwest province of Gansu, have been shut off because of weak demand. Workers while away the hours calculating how much power the turbines could have generated if there were more buyers, and wondering if and when they will ever make a profit.

“There’s not much we can do right now,” said Zhou Shenggang, a manager at a state-owned energy company who oversees 134 turbines here; about 60 percent of their capacity goes unused each year. “Only the state can intervene.”

China, the world’s largest emitter of greenhouse gases, has pointed to its embrace of wind and solar power and other alternatives to coal to position itself at the forefront of the global effort to combat climate change.