Chinese state govt is building them in response to poorly thought out federal govt incentives. That plus backup plans (since China had plenty of coal but needs to import gas, so it could easily be navally blockaded by the US). Also gas turbines are a specialty of the West (which again doesn't work well geopolitically), and their demand has massively outstripped supply (we're even seeing jet engines being converted into gas turbines) and the order backlog is years out - all of which doesn't jive with China's "build everything right f'n now" strategy.

China is building everything at a pace never before seen in history. Partly because their construction industry is a jobs program, and their economy is so dependent on it that they prefer building things at a loss rather than not building at all. Which is financially dumb, but welcome to politics.