Or someone can't read. No where in article does it state Coal capacity is flat, just coal growth has flattened significantly per 14th five-year plan (2021-2025). PRC peak coal is expected this or next year, and phase down / decline starting 15th five-year plan (2026-2030).
It looks flat because that's what adding 8GW to ~1200GW looks like. Adding only 8GW coal is one point article remarks as noteworthy, and the data comports.