ESsCO2

As part of the ESsCO₂ research project, a basic concept for an innovative, emission-free storage power plant was developed. The fact that CO₂ can also be stored in a supercritical state in cavities in salt formations over long periods of time is proven by natural analogues. Whether supercritical CO₂ (sCO₂) can be used as a working medium for the intermediate storage of electrical energy in a closed system and which thermomechanical, material, and safety aspects need to be taken into account was investigated in the ESsCO₂ research project together with partners.

Basic principle

In a closed system, CO₂ is transferred in a supercritical state between two salt caverns. If there is excess energy, the medium is stored in the deeper high-pressure cavern by means of a compressor. When energy is required, the sCO₂ is channelled from there via a turbine into the low-pressure cavern, and the electricity generated in this way can be fed into the grid. The advantages are the expected short start-up times, long service life, and low-maintenance operation.

Together with Institut für Geomechanik Leipzig GmbH (IfG) and the associated partner Czech Technical University in Prague (TU Prague), UGS GmbH worked on the research project in two sub-projects. The IfG analysed the design of the caverns and determined the thermomechanical boundary conditions in interaction with the rock mass and the fluid mechanical effects. Experts from TU Prague designed the sCO₂ turbine (without funding) and worked out the operating conditions for optimised power generation.

UGS GmbH developed concepts for the well completions and the above-ground peripheral facilities suitable for sCO₂ storage. One aim was to design the wells and facilities to minimise flow resistance (i.e. large diameters). When selecting materials, corrosion aspects were taken into account and translated into acceptance criteria for existing installations. A safety and commissioning concept as well as verification and monitoring systems for the operating phase were developed. Finally, the feasibility and development prospects were presented as part of a basic profitability analysis.

Prot durationjec: 1 January 2019 to 31 December 2021

Project management/funding body: Project management Jülich, Bundesministerium für Wirtschaft und Energie (Federal Ministry for Economic Affairs and Energy)

Project volumes of UGS GmbH: EUR 390,000

Funding rate of UGS GmbH: 40 %