There are ways, today, to make 60% efficient solar -> electric
We can increase this over 100% when we start understanding energy better.

Magnet motors will power all vehicles and hand tools.
Geothermal will handle all industry.

And this is before we even get to free energy technology.

If you wish to talk in "powers of reason" we should start at drilling an oil well.
How much that costs, how much that costs to maintain, and how much energy out vs energy in.

The tech i spoke of is cheaper, lasts about as long, and produces more energy.