With the continuing expansion of electricity generation from fluctuating wind power the grid-compatible integration of renewable energy sources is becoming an increasingly important aspect. Adiabatic compressed air energy storage power plants have the potential to make a substantial contribution here. The present article describes activities and first results relating to this technology that are being conducted within the European 'AA-CAES' Project. These interim results indicate not only the demanding design requirements for system components, but also the technical and economic feasibility of the concept.