A solar tower is sound engineering; this is the arrangement with mirrors and heating something like salt or sulfur. The heat differential makes steam that runs turbines. Photoelectric is the problem.
So of course that is why they need government funding - because it is such a good idea, and there are no sources of capital in the USA for capital other than the government.
The question is NOT technical feasability. Loans are made for economic reasons.
This is government subsidized loans in a market with government subsidized consumption.