These case studies are based on a diverse range of technologies and under specific market rules. They incorporate various program and policy mechanisms and include information on costs and the associated business cases for investment. Each case presented has its own unique set of characteristics and drivers, which is indicative of the diverse range of drivers for smart grid and DSM. The cases are at very different stages throughout the world. While some countries have completed first rounds of pilots and are building on lessons learned, the others are at earliest stage of these initiatives. The size, customer class, choice of technologies deployed, specific costs, benefits and business cases vary from case to case. Still, there are a number of best practices and common themes emerging from these cases that are likely to be useful for any stakeholder investigating or deploying Demand Side Management. Those best practices and insights are presented here. The key findings are a synthesis attempt of the broad range of the approaches tackled by the different smart grid demonstrators described by the 12 cases. It highlights the main lessons learned and best practices shared by the participating cases. These lessons learned mainly concerns technical approaches, customer engagement and market establishment. This publication was prepared for the International Smart Grid Action Network (ISGAN) by Working Group 2. ISGAN is organized as the Implementing Agreement for a Co-operative Programme on Smart Grids (ISGAN) and operates under a framework created by the International Energy Agency (IEA). The views, findings and opinions expressed herein do not necessarily state or reflect those of any of ISGAN’s participants, any of their sponsoring governments or organizations, the IEA Secretariat, or any of its member countries.