Simplification is not a synonym for deregulation. A simplification agenda requires a reassessment of regulations that are excessive, outdated, and ineffective in achieving their policy objectives. This should lead to cleaning up based on research. In energy and climate policy, there are many reasons why cleaning up may be necessary. There have been numerous policy developments, it is a complex policy domain with many interacting objectives. The legislative process, and power struggles between various actors results in complexity. Rules can also prove to be more complex to implement than expected, or less useful than imagined. To simplify energy and climate regulation, in this brief, we refer to our research on streamlining capacity mechanisms, the process for Projects of Common Interest (PCI), and the carbon market stability reserve mechanism. We also discuss how improved governance can be a way to simplify regulation with the examples of the ‘all TSOs’ and ‘all relevant TSOs’ processes, the regulatory oversight for EU-wide and regional entities established by EU legislation, and the Market Coupling Operation (MCO) function. We also make a preliminary scoping of a possible research agenda on simplification. We think there is room for improvements in areas such as the participation of consumers in the energy transition, the sharing of costs and benefits related to grid infrastructure, and the funds to finance climate action. We also think that there are claims by stakeholders that are opportune to investigate further, like the claims related to the regulation on methane emissions, the rules on cybersecurity, and many more beyond the ones we mentioned in this brief for illustration.