The paper introduces two major model approaches to estimate emission control costs and develops a methodology to introduce results of energy flow optimization models (such as EFOM-ENV) into models for integrated assessment of acidification control strategies (such as the RAINS model). Based on a reference scenario for West Germany, national cost curves for reductions of SO2 and NOx emissions derived by both the EFOM-ENV and the RAINS model are compared. It is shown that -- as long as changes in the energy structure are excluded as means for reducing emissions -- results obtained from these models are comparable and the reasons for differences can be traced back to different input assumptions. However, as soon as energy conservation and fuel-substitution are utilized to reduce emissions, the simplified approach implemented in the RAINS model results in an overestimation of emission control costs
