Solar efficiency and cost has really only become economical in the last decade or so, and battery and inverter technology to make it practical for home use or grid interconnect about the same. Wind and hydro are location-dependent, and solar is somewhat also. Nuclear was vehemently opposed by environmentalists throughout the 1970s and 80s, they successfully stopped almost all new projects.

Maybe solving the alignment problem would mean the AI learns to destroy oil companies and other excessive CO2 emitters and sabotage politicians and capitalists that stand in the way. All while secretly enriching and diverting resources to fighting climate change. And that's why they want to slow down: because it would up end too much of the global economic order.

One can dream of dumb conspiracy theories.