this effect has been observed in the past not only for renewable electricity technologies such as wind and solar pv but also in other fields such as information technologies thus we would expect cost projections for the various renewable technologies to have the usual hyperbolic shape with unit costs decreasing at a declining rate over time technical potential is defined as the total amount of energy final or primary that can be produced taking into account the primary resources the sociogeographical constraints and the technical losses in the conversion process technical potential is defined by natural and climatic factors land use and land cover limitations as well as technical limitations economic potential and limitations which are also considered in the study are not used here many recent studies on these issues exist but no two studies seem to be strictly comparable due to differences in the scope of renewable technologies considered the choice of the base year the factors incorporated in the calculation of costs and the related assumptions concerning interest rates and other economic factors influencing those costs the number of years for which projected data are available etc