In 2020, the Florence School of Regulation (FSR) published a comprehensive study peer reviewing major analyses in the area of energy decarbonisation with the aim of giving a coherent interpretation of their findings.[1] These data were the basis for further investigation of some key metrics for assessing the cost-effectiveness of different decarbonisation options with a view to informing targeted policy on this issue at the level of the European Union (EU). Just over one year on, much has changed, both in the world of energy and more widely. This short follow-up to the original and more comprehensive cost effectiveness study aims to take stock and frame developments in the past months in the context of EU energy policy, and to reassert some of the key messages from the 2020 publication that remain relevant. In so doing, the authors have updated key cost and capacity information according to some of the latest relevant publications, and have reflected on some of the challenges and opportunities presented by wider developments. The purpose of the study is not to propose a specific answer or trajectory regarding the balance of policies to decarbonise the energy sector. Instead, the aim is to highlight some key information relevant to policymakers charting the next energy sector decarbonisation steps.