The technology has been there for a long time. The economics are
getting better. Here is a corn/ethanol versus solar/photovoltaic
comparison.
An acre of solar cells in the desert southwest produces more energy than
300 acres of corn fields in the heart of our countries farm land
assuming 100 bushels of corn per acre per year and current technology
mass-produced photovoltaic cells with 15% efficiency.
The photovoltaic solar cells produce 665,000 KWH per year per acre.
Corn produces 2,344 KWH per year per acre.
The US uses 2.9*10^13 KWHs per year. Hence the US would need 10 times
its total land area in good crop land to fulfill its needs with Corn.
Only 20% of the US is crop land and that decreases each year.
With solar photovoltaic the US would only use 2% of its land area. That
is only 10% of the desert and other barren land that is not used.
