The GSI Helmholtzzentrum für Schwerionenfoschung GmbH (GSI) has a very energy-efficient and sustainable data center with the Green-IT-Cube, which is based on a technology with cold water cooling of racks and re-use of the dissipated heat. Originally planned as an environmentally friendly alternative solution for the accommodation of the computing capacity necessary to evaluate the data of the FAIR accelerator, considerable interest has emerged in the meantime from entirely marginal areas of research and industry. GSI now plans to establish the FAIR Open Lab, where Levels 3 and 4 of the Green IT Cube will be dedicated as a real laboratory for future research and development projects and the provision of third-party funded projects.