Capturing CO₂ at Aalborg Portland – And Catching My Breath on the Danish Hills

Earlier this month, I spent a few days at Aalborg Portland as part of my PhD at the Technical University of Denmark. Aalborg Portland is Denmark’s largest cement plant, and is one of the partners of the CASPER project – short for Cement cArbon Storage Pilot for Emission Reduction. Our goal? To help demonstrate the full CCS (carbon capture and storage) value chain from a real cement facility, moving one step closer to large-scale decarbonization of one of the world’s most CO₂-intensive industries.

But while most of my time was spent checking sensors, testing heat loss, and preparing the pilot plant for future solvent runs, I also made space for something a little more relaxing: biking through the scenic landscapes just north of Aalborg.

What is CASPER?

The CASPER project is an ambitious Danish initiative aiming to demonstrate and evaluate the entire CCS chain, from capturing CO₂ at Aalborg Portland, to conditioning, and eventually testing transporting conditions of the gas through a purpose-built pipeline. During the 2025 campaign, we will capture and condition CO₂ directly from cement plant flue gas. That CO₂ will then be analysed for quality and compared to relevant pipeline transport standards.

An essential part of the project is the test pipeline owned by Evida, where we’ll study how impurities in the captured CO₂ may affect transport and infrastructure. This kind of practical testing is key to enabling safe, reliable CCS implementation in the coming years.

The expected outcome? CASPER will deliver Denmark’s first full evaluation of a CCS value chain from a cement plant, generating valuable knowledge for future CO₂ infrastructure and regulatory planning.

 

Preparing the Pilot for CO₂ Capture

During this visit, we weren’t capturing CO₂ yet, the system was still in the preparation phase, using water to simulate fluid flows. Our focus was on heat losstesting of process equipment, getting to know the pipework and instrumentation layout, and preparing the system for upcoming solvent-based capture tests.

Even though it’s not glamorous work, this stage is crucial. Understanding the physical behaviour of the system and calibrating for consistent thermal performance ensures that when we switch to real solvents and start capturing CO₂, we can trust the data we’re getting.

It’s also great hands-on experience, there’s no better way to understand a carbon capture system than by walking through it, tracing each pipe, and solving problems as they arise.

From Carbon Capture to Danish Countryside

To make the trip a little more sustainable, I took the train from Copenhagen to Aalborg, a roughly five-hour journey through Denmark’s soft hills and open farmland. Aalborg itself is a small but lively city with a growing focus on green industry and luckily, it’s also a great place to bike.

I brought my bike with me and used my free time to explore north of the city. Just ten minutes out, you’re surrounded by green fields, wildflowers, and peaceful rural roads. Despite Denmark’s reputation for flat terrain, I found a few steep little hills that got the legs burning! Still, biking in the open air after a long day at the plant was a perfect way to clear my head and enjoy the Danish spring.