Some serious good news for a change!
The articles say: 4500 acres, 500 MW. This is about 7 square miles, or about 71.4 MW per square mile. There's your figure for comparison with wind and solar photovoltaic, in terms of power output per unit of land area.
Tests conducted by Sandia Labs show the Stirling-cycle solar system to be about twice as efficient as other solar systems.
We have plenty of hot sunny desert just waiting to do something useful.
500 MW is in the size range of a small nuclear reactor. By the way, the Slashdot article has some interesting discussion of various reactor technologies.
For anyone who's interested in a working demonstration model of a simple Stirling-cycle engine, go here:
http://www.newenergyshop.com/htm/new_energy_shop_en.htm
and click on the link for Stirling models. If I'm not mistaken, there are a few other companies also producing small Stirling models for educational and demonstration purposes.