Scenarios from the Intergovernmental Panel on Climate Change (IPCC) and the European Union's climate protection targets indicate the need to achieve negative CO₂ emissions in order to at least compensate unavoidable CO₂ emissions that will continue to occur in the future. Negative emissions mean that CO₂ is removed from the atmosphere, e.g. by releasing combustion exhaust gases from industrial processes into the environment which contain less CO₂ than the ambient air or by capture of CO₂ directly from the ambient air. Processes for direct CO₂ separation from air (direct air capture) have so far been associated with high CO₂ separation costs and high energy requirements.

By achieving highest CO₂ capture rates >98% by amine-based scrubbing or using innovative electrochemical process concepts, CO₂ neutrality or even negative emissions (residual CO₂ content <400 ppm) can be achieved at industrial plants - with technical and economic advantages compared to conventional DAC technologies.

Five test campaigns are closing knowledge gaps

The energy requirement of amine-based scrubbing rises steeply in the range of highest capture rates (>99.7%) with which negative CO₂ emissions can be achieved. So far, there is a lack of data to predict the process performance in this range with the existing simulation programs. In DRIVE, these knowledge gaps are closed with the results from a total of five test campaigns at the CO₂ scrubbing pilot plant in Niederaussem with a total duration of 14 months. It is not necessary to make any structural changes to the pilot plant or retrofit any components in order to implement the targeted operating mode.

Following a holistic approach, a large number of process parameters as well as emissions and solvent consumption are being investigated. Long-term testing of the operating mode with the highest CO₂ capture rates over around 10,000 hours in 24/7 operation provides reliable results for the design of industrial applications. The analysis of the test data allows the optimized design of CO₂ capture plants for the highest capture rates and enables a detailed economic evaluation.

The project at a glance

DRIVE (Deep Removal of CO₂ and InnoVative Electrification concepts) started in December 2023 and is a CETP (Clean Energy Transition Partnership) project that will run for three years. The international project is a cooperation of TNO as coordinator, RWE Power AG, CEMEX, Hovyu, the Heriot-Watt University, the Instituto de Engenharia Mecanica, the Institouto Anaptixis Epicheirimatikotitas Astiki Etaireia, SSE Thermal Generation, Total Energies und the Technische Universiteit Eindhoven. In addition to the work in Niederaussem, the partners are also testing two alternative separation techniques that use aqueous solutions of hydroxides instead of amines. The hydrogen carbonates formed here during separation in the solvent are not regenerated by increasing the temperature but electrochemically, which could offer advantages at the highest capture rates. Systems from the partners TNO and Hovyu have already been tested on a pilot plant scale and are to be tested under real operating conditions as part of DRIVE after further optimization.