as a result nearterm technology and policy decisions are critically important for leveraging longterm change but the temporal dimensions of this technological differentiation in energy systems are extremely long in the mediumterm only modest nichemarket inroads of solar pv into the global energy system are expected only by have scenarios clustered either around relatively small solar pv markets ej assuming no or low c emission constraints and high investment costs or around relatively large solar pv markets ej under stringent c emission constraints and low investment costs