R-Aces means a step-change in the contribution of European Industry to the climate targets of the EU. The sector after all represents 25% of all energy demand – and 50% of all cooling and heating - on the continent; yet only 16% comes from renewables. By focusing on collective measures and clustering, the efficiency of industry can be drastically increased. The focus of R-Aces therefore is to turn high-potential, high-impact industrial clusters into EcoRegions that achieve at least a 10% reduction in emissions. An Eco-region is an area where energy, material and information exchanges occur between various companies and actors to reduce waste and energy/material consumption. Each region is centered on an (eco-)industrial park or (eco-)business park, linked to its surroundings by a 4th/5th generation district heating/cooling network. The consortium sees this project as a capping stone, condensing the knowledge and experience gathered throughout H2020 into a set of three focused tools embedded in selected support actions. The tools consist of an assessment tool; legal decision support for joint contracts; and a smart energy management platform for clusters. The support actions are built around peer-to-peer learning, more formal coursework and serious games. Together they enable a cluster to really become an EcoRegion and set up meaningful energy collaboration. The entire package of tools and support is aimed at the high-potential clusters identified in the European Thermal Roadmap. It will be validated in three of them (all are part of the consortium); actively deployed in another seven; and disseminated to ninety of them. In addition, the tools and support methodology will be made available to third parties in a sustainable way after the end of this two-year project. The project consortium consists of the entire value chain needed for energy collaboration – suppliers, ESCO, cluster managers, support – and represents many years of proven experience in this field.