Variations in the solar resource are probably the first and main consideration. You can use local weather stations where available, otherwise satellite data (eg from NASA's website) or commercial databases such as Meteonorm. Also there is quite a comprehensive set of data files in the SAM software
Other important considerations are
local environment: plants and animals that could be affected by the system; community support and buy-in.wind, hail, rain, snow profile for the location in question. if there are high/tropical winds then it will increase the plant cost.flight paths and roads near the plant which could be affected by glint and glareproximity to a local town where staff will be able to live both during construction and later during operationproximity to a electricity transmission line with available capacityavailability of water for mirror cleaning and steam blowdown.cost (and availability) of electricity in the area. If remote, electricity/energy may be very expensive, which will enable a high price for electricity sold from the plant.quality of road to the plant, required to bring equipment and materials to sitepolitical stability of the region -- potential impact on perceived bankability of the project.
Many of these items will have a large influence on the cost of the plant and/or the revenue it will generate during its life. Others relate to environmental and risk factors and are also critically important to consider.
Hope this helps!!
