Several hybrid and solar-only configurations for molten-salt power towers were evaluated with a simple economic model, appropriate for screening analysis. The solar-specific aspects of these plants were highlighted. In general, hybrid power towers were shown to be economically superior to solar-only plants with the same field size. Furthermore, the power-booster hybrid approach was generally preferred over the fuel-saver hybrid approach. Using today＇s power tower technology, economic viability for the solar power-boost occurs at fuel costs in the neighborhood of $8.90 to $15/MW h ($2.60 to $4.40/MBtu, low heating value) depending on whether coal-based or gas-turbine-based technology is being offset. These fuel prices exist today in certain areas of the world (e.g. India). The cost of CO2 avoidance was also calculated for solar cases in which the fossil fuel cost was too low for solar to be economically viable. The avoidance costs are competitive with other proposed methods of removing CO2 from fossil-fired power plants and appear to be within the range of interest (<$29/mt) to environmental protection organizations such as the Global Environmental Facility.