[photochemsyn]

If you want to have an industrial-scale civilization, well, 100% renewable might sound good but the scale is not enough for factories and modern infrastructure needs. Compare and contrast the average usage in Zambia vs. the USA, per person:

per capita Zambia = 669.89 kWh

per capita USA = 11,695.27 kWh

Now the USA isn't the most efficient user of electricity (probably the least), but still, asking the US economy to function with only 1/20th the normal energy use? Implausible at best.