The Centre for Solar Energy and Hydrogen Research Baden-Württemberg (Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg – ZSW) has achieved a ‘milestone’ stage in the progress of its direct air capture (DAC) technology. The demonstration system developed in the Stuttgart laboratory has been running steadily in the research undertaking for over 10 000 hours and has so far been able to remove almost five tons of CO2 from the atmosphere.
“For a rapid transformation towards a sustainable energy system, we need technologies which can be scaled up to high performance classes. The 10 000 hours of experience in operating the system indicate that our DAC technology works reliably and show that we can take the next step in increasing the dimensions,” commented Dr Marc-Simon Löffler, head of the department of Renewable Energy Sources and Processes at the ZSW. The demonstration system is designed to reach a production capacity of around 10 tons of carbon dioxide per year. The carbon dioxide removed from the atmosphere by means of DAC technology can then be used for the climate-neutral production of synthetic fuels for vehicles and aircraft, for example, or as a raw material in the chemical industry.
DAC system advantages
“There are many outstanding features to our technology. It is robust, easily scalable and very efficient. The heat given off at the various steps of the process can also be put to good use,” said Dr Löffler. The CO2 taken from the atmosphere undergoes a process of absorption in a scrubber using a polyethylene imine of high molecular weight, followed by desorption and concentration at temperatures of around 100 degC in a subsequent step. The DAC system is low in electricity consumption, requiring around one kWh for one kg of CO2, as a large proportion of the energy demand can be covered by the CO2 separation process. The main benefit of the process developed by the ZSW is the consistently high quality of CO2 capable of synthesis. It is also advantageous that the technology can be easily scaled up to high performance classes.
The ZSW is now priming its DAC technology for industrial use. There are plans to operate a system enlarged by a factor of 100 with a generating capacity of around 1000 tons of CO2 per year in a real environment from 2025 onwards. The cost of producing CO2 could be reduced to less than 100 euro per ton if scaled up further to the size required for e-fuel production plants.
Using the technology
The ZSW is working in parallel on equipping industry for next generation technologies that can benefit. “DAC comes with the promise of great potential for value added for mechanical engineering firms, plant construction companies and the supply industry. We are reaching out to industry with our project ‘Direct Air Capture made in Baden-Württemberg’ in a bid to pass on the importance of carbon dioxide as a raw material and the future markets,” said Dr Löffler. Companies in Baden-Württemberg will be approached to this end and asked to engage in an industry-wide dialogue.
The Baden-Württemberg Ministry of Transport is funding the DAC-BW project to the tune of €1.39 million.