Parabolic trough powerplants nearing PPA end: Retrofit or replace?

The continued decrease in the cost of photovoltaics, particularly in comparison to concentrating solar thermal power plants has led to a recent case where a CSP plant was decommissioned in favour of replacement with a pure PV plant. In this paper a second option is considered where the existing CSP power plant is retrofit with a bolt-on PV apparatus that achieves 93% of the output of the PV replacement but at 18% of the cost.