The paper analyses regulatory cooperation in multi-level governance. It draws rival hypotheses from the experimentalist governance and the shadow of hierarchy theoretical frameworks. It compares policymaking in the power and gas sectors in a number of regulatory areas, all governed by the same formal institutional architecture set up by the so-called “Third Energy Package”. Finally, it does not investigate the diffusion but rather traces the use of institutional mechanisms such as impact assessments, peer reviews, and benchmarking. It therefore offers an empirical study of regulatory policymaking and governance, aiming to contribute improving our (currently weak) understanding of under what conditions and how, if at all, actors cooperate for revising goals, performance indicators, and rulemaking procedures themselves.
