You are correct on both points. But you have to keep in mind that these projects were conceived more than 5 years ago, when everyone was hesitant to build a $2b

You are correct on both points. But you have to keep in mind that these projects were conceived more than 5 years ago, when everyone was hesitant to build a $2b salt plant. When you combine big money with old engineers, you get very conservative (with respect to technology). For comparison, Solar Reserve has a salt plant under construction: http://www.solarreserve.com/what-we-do/csp-projects/crescent-dunes/ http://www.solarreserve.com/what-we-do/csp-projects/crescent...