CAGE is a demonstration project for new drilling, expansion, and stimulation technologies that offer increased control and security in the development and application of geothermal reservoirs in carbonate rocks. This will ultimately reduce investment and usage costs, while also increasing the geothermal energy output. Based on physical projects in the Netherlands with the project partners, a range of different technologies (e.g. borehole expansion using composite casing) are and will continue to be implemented and evaluated. For now, the carbonate rocks can range up to a depth of 1.5 km. As part of the contributions of Germany/IEG to CAGE, qualitative monitoring is being provided for technical drilling processes such as radial jetting for drilling to stimulate, i.e. increase, the “flow rate”. This combination of technologies could significantly improve the quality and efficiency of jetting-based stimulation processes.