Selected strategies to reduce acidic deposition in the U.S. Several SO2 emission reduction strategies are examined and their attributes clarified. The effectiveness of each method is measured by the changes it produces in total surfur deposition.
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Environ. Sci. Technol., Vol. 17, NO. 10. 1983
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1983 American Chemical Societv
David C. Streets Duane A. Knudson Jack D. Shannon Argonne National Laboratory Argonne, Ill. 60439 Although the research needed to fully characterize acidic deposition and its range of effects is many years from completion, political initiatives are being taken today to formulate control programs aimed at reducing the emissions of atmospheric pollutants believed to be responsible for environmental damage. Information on what effects such emission reductions would have on acidic deposition is incomplete, and there is no certainty that decreases in emissions would significantly reduce the adverse effects of acidic deposition. Nevertheless, the political process is moving ahead rapidly at both national and international levels and may be outrunning the pace of scientific research. This article is an attempt to shed light on this controversial policy issue by examining the attributes of several plausible acid deposition control strategies for the U S . It discusses the costs of these strategies, the emission reductions that would be obtained, and certain secondary effects they would have on selected regions of the country. Rather than attempting to complete the cost-benefit equation-which is arguably impossible given the current state of knowledge-this study provides some measure of the potential effectiveness of these strategies by estimating consequent reductions in sulfur deposition. It describes a systematic approach to portions of an organized cost-benefit analysis of acid rain legislation, but it is not intended to provide the definitive answer to the problem. (Ecological benefits are not even addressed here.) Many of the components necessary for a complete assessment are being developed in various government and utility studies. Despite the fact that acidic deposition and its effects are not fully understood, it is clear that certain types of strategies could be implemented to reduce precursor emissions or otherwise mitigate effects. This article emphasizes the approach that has the greatest chance of being implemented in the U S . : continuous reduction in emissions of sulfur dioxide from electric utility power plants. While this is the most likely approach, other options are also discussed briefly: a decrease in nitrogen oxide emissions, a reduction
in industrial or transportation emissions, intermittent fuel switching, and receptor mitigation (lake liming). The study examines several hypothetical sulfur dioxide control strategies, as well as other strategies that are currently being debated by congressional committees. Results are presented for the year 1995, based on the expected outcome of a 10-year program instituted in 1985. It is hoped that this analysis will contribute to the establishment of economically and environmentally sound policies for dealing with acidic deposition.
Analytical approach To accomplish the objectives of this analysis, projections are made of the effects of various emission reduction strategies, each of which is implemented in the coal-fired electric utility power plant sector. The year 1980 is used as a base year; against this base are compared certain effects the following five alternative approaches would have in the year 1995: no specific acidic deposition control strategy (B95), a mandatory coal washing program (CWM). ,- - -,, a ceiling on allowable SO2 emissions of 2 lb SOz/106 Btu (CP2), the Stafford bill, S. 3041 (STF), and the D’Amours bill, H.R. 4816 (DAM). These approaches were chosen for close examination because they represent different conceptual approaches to a control program and because they cover a wide range of emission reductions. Other hypothetical approaches and congressional bills are discussed at appropriate points in the text. The first three of these strategies-B95, CWM, and CP2-were analyzed in a joint study performed for the EPA, the Department of Energy (DOE), and Argonne National Laboratory by Teknekron Research, Inc. ( I ) . In the Teknekron study, the Utility Simulation Model (USM) was used to project the effects of several control strategies for electric utilities (293). The USM consists of a number of interconnected computer modules and data sets that simulate decisions involved in utility system planning and operation and the impact of these decisions on utility finances and the environment. The model is driven by a set of exogenous parameters that include electricity demand, financial market conditions, fuel characteristics and availability, the use of advanced technologies, and environmental reg-
ulations. It simulates the joint operation of the various types of generating units and various capacity classes owned by all the utilities within a state. Output from the model includes fuel use, electricity generation, capital and equipment requirements, releases of environmental pollutants, financial statistics for utility firms, and average electricity prices. The results of some of these control strategies were published earlier ( 4 ) , and this article draws on these results for costs and secondary impacts ( 2 , 4 ) . State-level emission reductions for B95, CWM, and CP2 were calculated separately for use in long-range transport modeling ( 5 ) . The USM results were obtained in 1980 and 1981 using the original version of the model employed by Teknekron Research, Inc., for EPA and DOE. The Universities Research Group on Energy (URGE), based at the University of Illinois at Urbana-Champaign, is currently designing an improved version of the USM called the Advanced Utility Simulation Model (AUSM). The values of the exogenous parameters reflect views of the future that were appropriate in 1980. Nevertheless, the results presented here are the best projections currently available, and improvements must await development of the AUSM. The other two strategies-STF and DAM-are analyzed in a recent report, together with the other major acid rain control bills that were introduced into the 97th Congress: Mitchell (S. 1706), Moynihan (S. 1709), and Moffett (H.R. 4829) (6).It is difficult to project with any accuracy the costs of implementing each of these bills because of the many options they give the states for achieving the required emission reductions. In this study, therefore, only approximate cost estimates for the bills are provided, with no attempt to project secondary impacts. The Congressional Research Service has summarized analyses of the acid rain control bills that have been performed to date (7). The cost estimates in these analyses are in general agreement with those presented here. The analysis in this article is restricted to the so-called acid rain mitigation study (ARMS) region, which covers the 31 states east of and bordering the Mississippi River and the District of Columbia (see, for example, Figure 1). This is the region addressed in the bills considered here and commonly used in technical analyses of the acid rain issue. After discussing the regional costs Environ. Sci. Technol., Vol. 17,No.
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and emission reductions associated with each strategy, this article goes on to examine what effect each has on the following parameters: state-level emission reductions and costs, regional electricity prices, regional coal markets, and sulfur deposition. The reductions in sulfur deposition resulting from emission changes are modeled using the advanced statistical trajectory regional air pollution (ASTRAP) model (8). Finally, the implications of the various strategies are discussed and compared with other approaches to reducing the potentially adverse effects of acidic deposition.
Specifications of each strategy 895. The 1980 base case (B80) is compiled from a unit-level inventory created from DOE and EPA sources (9). Utility emissions are calculated from data on actual fuel use in the DOE/Federal Energy Regulatory Commission Form 67. The 1995 base case (B95) projects the emissions from utility sources in 1995 in the absence of any acid deposition control legislation. It includes new growth and retirement of older units and assumes that compliance with state implementation plans (SIPs) is achieved by 1985. Older units that were on-line prior to 1950 and smaller units with a generating capacity
