This volume consists of revised selected papers presented at the 3rd and 4th International Conference on Smart Energy Research, SmartER Europe 2016 and 2017, held in Essen, Germany, in February 2016 and 2017. The 13 full papers included in this volume were carefully reviewed and selected from 25 submissions. The papers discuss recent advances and experiences in building and using new IT-based solutions for Smart Grids and Smart Markets combining the knowledge of different disciplines such as engineering, business management and economics as well as computer science. They reflect the versatility and the complexity of the transformation process in the energy sector and also show the great need for research that is required to achieve the high targets for a digitized and sustainable energy landscape.