Right, but decades ago coal was the cheapest source of power. We didn't have cheap renewables in the 70s. Solar is cheaper than coal in China.* They could certainly grow (at least) no slower by building huge amounts of renewables rather than coal.

*(I'm not sure if this is on a "spot" basis or annualised to account for intermittency, but then it probably doesn't account for the negative externalities of coal either so let's chalk it up to a draw.)