First, solar thermal technology is a more resilient approach. It is simpler to manufacture than photovoltaics; no billion-dollar clean rooms are needed to keep impurities out of panels. Polished mirrors and steel girders are easier to source and maintain than PV cells. Mirrors also last a lot longer (sometimes decades) than PV panels.
The project team is also forgoing a $2B loan guarantee simply because it claims its investors find PV more attractive. That is simply stunning. These genius investors have not done their homework on the technology at all. It's worth noting that the project retained Citigroup and Deutsche Bank to seek investors. Those two financial institutions were not exactly known for their adroit management of their own balance sheets during the 2008 credit crunch. Can you see the sales pitch now? "No, you don't want those boring mirrors. PV is what you really want because it's more exciting." Bankers are skilled at putting words in the mouths of the gullible rich with whom they have profitable relationships.
I am grateful not to be an investor in a complicated energy installation that will require a complete redesign of its enabling technology and supply chain. I'd rather hold out for a decent solar thermal project that investors are smart enough to see through to completion.
Full disclosure: No positions in the two banks mentioned, or in this energy project.