"I really wish that articles like this would give more context for all the numbers that inevitably get thrown around. > China Huaneng Group Corp.’s 845-megawatt power plant What percent of the city's electricity is that?"

Humanity uses about 17 terawatts of generated power (electricity plus transportation plus …), about 15 from fossil fuels, of which coal generates more GHG that all but the dirtiest oil and the leakiest NG facilities. That plant is probably used about 80% of the time, so it represents about 675/17,000,000 of humanity's power use and something like twice that much of our GHG generation.

We think we can generate about 500GT CO2e of GHG net before reaching 3°C warming (but that involves a lot of guesses), which is a level that seems civilization-destablizing to many observers (wild, but necessary guesses). Coal creates about 1kg per kWh, so convert from 675MW … 60sec60min24h365d675,000kW = 21,286,800,000,000 kg/yr, or ~21GT/yr, or 4% of that budget.