Hi Robin.
My back-of the-envelope calculations for a flat panel
solar collector using water as a heat transfer fluid
to heat anhydrous ammonia (or propane) stored in tanks with
nighttime black-plate radiative or daytime cooling tower heat rejection
operating at 10% Carnot efficiency (140-80 F) could easily muster
about 5,000 kW-hr per hectare day.
That comes out to about 4.0 square miles of collector that
can be used for Texas Style barn dances to pay for the Solar Tower losses (where less
than 1.0% heat as work is extracted from the solar-heated air).
Obviously an unlimited free pass for Richard Macaulay and Willie Nelson. :-)
Fred
