Money terrible spent, just another billion poured down the drain on inefficient renewable energy technologies that would have been much better spent developing better technologies.
For a billion dollars you could hire five hundred brilliant (or at least clever) scientists and pay then each $200K pa for ten years to work on promising technologies in photovoltaics, ranging from sexy stuff like multiple exciton generation to prosaic stuff like how to make silicon sheets cheaper.
money spent isn't money burned--it paid people's salaries, it helped people gain skill and experience that will apply to future projects, and the total economic benefit (not just in dollars, but in capabilities and human capital), is a much broader picture than this one power plant and its dollar per mwh number.
That sort of napkin math doesn’t take into account any economic or political realities, not to mention a stack of research papers generates 0Mwh.
When this plant was being engineered, many projected pricing trends for photovoltaics would have still kept it economical today. In that time China heavily increased their subsidizing of that sector which has been the overwhelming cause for pushing pricing down and is still the case today.
If things played out differently, which could have easily been the case, this would have been a good solution. I think it’s wise to diversify your bets across a number of solutions when you’re implementing a state level program and you should count on some of them being bad ideas. Media will jump on the half dozen failures from dozens of successes which overall is a good ROI.
Unless all the scientists do is theorectical work, you're going to need a lot more than that to pay for equipment, materials and other resources required to actually do some experiments, develop poc's etc.