Fossil fuels --- verses --- renewable green energy.

Fossil fuels displaced renewables and industrialized civilization became possible. A return to renewables is not possible without horrific toll in human death.

All energy is free: it was all created at the Big Bang and it cannot be destroyed.

But collecting energy and concentrating it so it can do useful work is expensive. Fortunately, nature has collected and concentrated energy for us.

Energy concentrated in ancient now dead stars is now available to us as radioactive materials.

Solar energy collected by growing things over geological ages is available as fossil fuels.

And solar energy collected by evaporation of water over large areas is concentrated in river flows.

This is why hydropower continued to be used but people abandoned using the diffuse energy from wind power, solar power, biomass burning, and the power of muscles (provided by slaves and animals) when the greater energy density in fossil fuels became available by use of the steam engine .

The displacement of renewables by fossil fuels enabled the food and industry required for an industrialized civilization. A return to renewables would remove any possibility of civilization feeding its population.