Like other Central European countries, Poland faces the twin challenges of improving environmental quality while also fostering sustainable economic development. In this study we examine the costs of different standards for air pollution control, and the cost savings from using incentive-based policy instruments in lieu of more rigid command-and-control policies. The comparisons are based on the results of a simulation model of energy use and air pollution control for the Polish economy over 1990–2015. The model simulates least-cost energy supply decisions under different environmental policy assumptions, the corresponding emissions, and the cost of achieving the specified policy objectives. The model results suggest that incentive-based policies will have efficiency gains over command policies that are at least worthy of consideration and may be quite substantial. The size of the gains in practice depends in part on how much flexibility is built into the command approach, e.g., capacity for intrafirm trading as well as alack of technology-specific requirements. To achieve these gains, an increase in the current levels of emissions fees is desirable both to strengthen abatement incentives and to improve the capacity of the Polish government to overcome past environmental damages. However, it seems highly unlikely in practice that fees could be raised to the levels necessary to meet current Polish emissions standards. To make further headway, an evolutionary approach to emissions trading patterned after (and profiting from the experience with) emissions trading in the U.S. seems useful. The program could start out relatively modestly and increase in ambitiousness as the Polish economic transition proceeds.