Accelerating energy technology innovation is crucial to meet energy and climate goals, to support economic growth and to enhance energy security. Successful development and deployment of innovative energy technologies requires that stakeholders from both the public and private sector share knowledge, work collaboratively and, where appropriate, pool resources to deliver integrated, cost effective solutions to common challenges. Four decades ago, the founders of the IEA had the foresight to create a multilateral technology collaboration mechanism – the IEA Implementing Agreements (IAs) – that has withstood the test of time and today is more relevant than ever to delivering solutions to global energy challenges. This network of experts produced a range of noteworthy results, including inventions, pilot plants, demonstration projects, databases and development of standards. The year 2015 marked the 40th anniversary of the mechanism as well as the rebranding of the IAs as Technology Collaboration Programmes (TCPs). This publication provides an overview of the activities and recent accomplishments of TCPs. The 39 TCPs operating today involve about 6 000 experts from government, industry and research organisations in 51 countries around the world. Participants in TCPs have examined more than 1 900 energy-related topics in the areas of energy efficiency, renewable energy, fossil fuels, fusion power and cross-cutting issues. The unrivalled breadth and coverage of analytical expertise seen in TCPs are unique assets that will underpin for the years to come IEA efforts to support innovation for energy security, economic growth and environmental protection.