The Chinese region of Inner Mongolia expects to start work this year on two new “flexible” power plants mixing coal and green energy. The plants, which will provide power to the eastern economic hubs of Shanghai and Jiangsu province, mark a major strategic shift in the use of coal because it will now be used to plug gaps in the power generated by wind and solar energy rather than being the primary source of energy. Inner Mongolia is home to around a quarter of China’s coal reserves but has also...