My recommendation which China is already seems to be taking is to go for nuclear power and solar in that order. Maybe add some hydropower to the mix but they have a plenty of it.
The chief problem is that they're not ramping up nuclear quickly enough, and it's hard to deploy in desert west of the country.
And thanks to our persistent self-sabotage there's civil unrest related to these power plants.
The nuclear is to be used to ramp production of solar PV and batteries cleanly, then decommissioned. Timeframe would be 25 years.
Decommissioning of current old reactors is a problem already but there's really no alternative - ramping solar PV with standard energy sources would be bad. A lot of reactors are expected to shut down by 2025...
I assume that they're taking an approach of using renewable energy where possible and fossil fuels when that's not enough.