This chapter discusses the interaction between four central EU climate policies: the emissions trading system, renewables, carbon capture and storage (CCS), and energy efficiency in buildings. In addition to forming key parts of EU climate policy, these policies exhibit interesting differences with respect to steering methods and competence distribution. Four main conclusions about interaction and policy coherence that follow from our analysis. First, most of the climate policy areas developed in line with issue specific dynamics. While the making of ‘policy packages’ certainly helped create a new policy drive after 2005, it brought fewer interaction effects than the ‘integrated climate package’ rhetoric would lead us to believe. Second, entrepreneurial interaction (bargained and persuasion) cannot be expected to create good coherence. Third, actual spillover effects will not automatically feed back into the policy process and create policy coherence: policy makers may very well continue to treat all policy areas as separate islands even when it is obvious that they are more like streams that merge into each other. Fourth, policy interaction seems more inclined to affect the centralization of control than the steering method.