Jurisdictions that rely on emissions trading to control emissions often utilize other environmental or energy policies as well, including policies to support renewable energy and reduce energy consumption. Overlapping policies produce economic interactions that can lead to quite different outcomes from what might be predicted after examining individual policies separately. Prior literature on policy interactions has primarily focused on cap-and-trade systems, where aggregate emissions are fixed by regulation but emissions prices respond. However, jurisdictions are increasingly turning to alternative forms of emissions markets, including a range of rate-based emissions trading systems, in which both emissions quantities and prices are flexible and the significance of policy interactions is less understood. This paper extends the literature by considering the outcomes under a range of emissions trading systems—not only cap-and-trade, but also several forms of tradable performance standards—and under a variety of overlapping policies, including subsidies to renewables and taxes on electricity.