This document from 2005 looks into the potential of solar thermal development for Iran. Although Iran has a very high level of incoming global radiation, the use of solar energy in general is very low. One of the key-obstacles for solar thermal is the low level of energy prices. This can be explained due to the significant subsidies for fossil fuels which blocks private investments in energy saving activities.
On the other hand, the report clearly states the advantages an increase in solar thermal could have for Iran. The investments in solar energy are without risks and can provide high revenues for the Iranian economy. In addition, the saved oil could be sold to the work market which would lead to additional income.