We would like to take this opportunity to thank all of Energy & Environmental Science’s reviewers, and in particular highlight the Outstanding Reviewers for the journal in 2019, as selected by the editorial team for their significant contribution to Energy & Environmental Science. We announce our Outstanding Reviewers annually and each receives a certificate to give recognition for their contribution. The reviewers have been chosen based on the number, timeliness and quality of the reports completed over the last 12 months.