Another solar company which received $2.1 billion in loan guarantees from the Obama Administration has gone bankrupt. The good news is that it has not spent much of that taxpayer money, and its bankruptcy is probably due more to the bankruptcy of its German parent, which in turn is likely related to the huge cuts Germany has made in its feed-in tariff subsidies.
The big asset possessed by Solar Trust is the Blythe solar project, a planned 1000MW facility that apparently has all of its permitting in place. The Blythe facility was originally going to be a solar-thermal facility, with adjustable mirrors focusing the sun on a central boiler that would in turn power turbines. This plan was scrapped last year in favor of a more traditional PV technology, and I know local company First Solar has been hoping to save itself by getting the panel deal (First Solar also has been hammered by the loss of German subsidies).
If we take the cost of this planned 1000MW facility as the stated $2.8 billion (of which 2.1 billion would be guaranteed by US taxpayers), we see the basic problem with solar. A new 1000MW natural gas powered electric plant costs no more than about $1 billion. It produces electricity 24 hours a day. This solar plant, to be the largest in the world, would produce 1000 MW for only a few hours of the day. That area of desert gets about 7 peak sun hours per day (the best in the country) so that on a 24 hour basis it only produces 292 MW average. This gives it a total capital cost per 1000 MW of $9.6 billion, making it approximately 10 times costlier than the natural gas plant to build. Of course, the solar plant has no fuel costs over time, but solar is never able to close the gap over time, particularly with current very low natural gas prices.
Update: Apparently the $2.8 billion was just for the initial 484 MW so you can double all the solar costs in the analysis above, making the plant about 20x costlier than a natural gas plant.