Now comfortably swaddled in new tariffs , American steel firms have had a good few weeks. But U.S. President Donald Trump’s other favorite industry hasn’t fared so well. BHP, the world’s largest miner, last Thursday departed the coal industry’s lobbying group citing disagreements on climate change. Still, the most worrying recent development is in China, where the nation’s power plants—the world’s biggest buyers of thermal coal—are in dire financial straits. The trouble is the result of previous state interventions to help coal miners. In 2015, rolling coal bond defaults threatened China’s financial sector. Beijing’s response? Massive intervention to curb coal production, which pushed prices and margins higher. It was a wonderful idea—if the government only needed to worry about coal firms. Unfortunately, China’s electricity producers, which can’t easily pass on coal price increases because of power price controls, are now running into trouble. Huaneng Power International , HNP 0.24% […]