Aidan,

How much power would the solar thermal provide at the peak period of 5-8pm?

There is a lot of vacant land in the desert areas. Send it to the seaboard as dc power and convert it to ac power. Minimal loss by transmission.
Coal is dead and filthy.

Doog,

And what do they do at night? Candles?

SM, the solar thermal seems to work OK but it seems that the cost of
their output is the problem.
There does not seem to be a realisation that you have to build two
generation systems. One has for political reasons has to be able to
carry the whole load and produce no CO2 and the other has to be able
to carry the whole load on a still day at 5pm peak in winter or summer.

Those are the two operational extremes. It must be a very expensive
system. Some suggest storage to avoid going to those extremes.
However, storage of any sort seems to be expensive with hydro probably
the best especially if you want weeks of storage as the cost to build
would not be linear with capacity.

Pity some in authority did not think about these problems beforehand.
Now they have to patch it up. Anyone know when Liddel closes ?