This study provided by Policy Department A at the request of the European Parliament’s Committee on Industry, Research and Energy (ITRE) shows that the energy-system related impact of Brexit on EU citizens and companies will be limited. The EU will be able to complete its market, achieve its climate and energy targets and maintain supply security. It appears likely (although not guaranteed) that the UK will continue to maintain sensible environmental policies and safeguard the rights of EU companies in the UK. However, special attention on the impact of Brexit on the Irish energy system is warranted.