Ethanol From Waste Straw

PV has considerable collateral damage:

Manufacture of Solar cells create large scale toxic waste products.
Best to do this in space, not on Earth.

Terrestrial PV systems require batteries for energy storage, this is
another major toxic waste problem.

The cost of the storage systems, whether batteries or flywheels or
whatever, make terrrestrial PV uneconomic. SPS does not need
storage systems.