consistent set of ground rules for all units. This was the first analytical step of the comparative assessment, and it entailed listing information (some detailed, some summary) for each of the energy systems. Information categories cover the technical, economic, environmental, and societal issues mentioned earlier. Two important functions of the side-by-side analysis are: (1) providing the decision maker and analyst with a normalized comparison,* and (2) functioning as an intermediate step between the technology characterizations and the alternative futures analysis. 2.6 ALTERNATIVE FUTURES ANALYSIS The alternative futures analysis compared alternative energy-supply systems (i.e., alternative mixes of coal, nuclear, and SPS technologies) under different levels of energy demand (i.e., alternative supply-demand patterns). This analysis addressed synergistic impacts or those that result from aggregation of single-plant effects. An integral part of the analysis was the creation of scenarios (e.g., statements about future supply, demand, lifestyle, resources, and regulation) to serve as inputs to other analyses. The primary objective of the alternative futures analyses was to provide a comparison of the impacts of alternative technologies under several different assumptions of future conditions. The following criteria were considered in the choice of scenarios that drive the alternative futures: • A limited number of scenarios should be used, and they should be credible and representative; • They must illustrate a suitably large range of alternative policies, and economic and social conditions (or at least those of major concern or interest); • They must not produce a flood of data that would tend to overwhelm analysts and the decision-making process; • They should highlight or identify major categories of issues for further analysis; and • Uncertainty should be included in a consistent and efficient manner, conveying useful information to the decision maker. *The term "normalized comparison" simply means that quantifiable impacts are expressed in amount of impact per unit output of electrical energy, e.g., per megawatt-year (MW-yr). Thus, a 5-MW system that provides energy continuously for one year and expels 1,000 tons of pollutants to the environment in the process will be characterized by the normalized amount of 200 (= 1,000 v 5) tons of pollutant per MW-yr of electrical energy; similarly, a 1 MW plant that operates for half a year and produces 50 tons of pollutants is assigned the normalized amount of 100 (= 50 I 1/2) tons of pollutants per MW-yr.
RkJQdWJsaXNoZXIy MTU5NjU0Mg==