Accurate CO₂ Measurements is Essential for Longship

One of the key objectives of the Longship project is to demonstrate that CO₂ can be handled safely and efficiently – from capture to permanent storage. To achieve this, precise measurement is essential. Not only as a technical requirement, but also as a prerequisite for regulatory reporting, safety, and public trust. Longship operates with strict specifications which enable both operational reliability and accurate mass balances.

CO₂ Must Be Measured at Every Stage

The capture facilities are responsible for measurements up until the CO₂ is loaded onto ships. From that point onward, Northern Lights takes over responsibility – from transport to subsea storage. Every delivery is thoroughly documented. If the CO₂ does not meet the technical specifications, it can be rejected at the loading stage.

The capture phase begins with the separation of CO₂ from flue gas, followed by purification, cooling, and compression into liquid form. During loading from the capture facility, pressure, temperature, density, and quality are measured. Onboard the ship, each tank is continuously monitored. Upon arrival in Øygarden, measurements are used to verify the delivery and calculate any losses. After injection, the storage site is continuously monitored to ensure that the gas remains safely sealed.

Measurements are carried out using a combination of field instruments and laboratory analyses. The most critical instruments measure quantity, composition, pressure, and temperature. All instruments are regularly calibrated to ensure compliance with international standards.

Documenting Climate Impact

Longship demonstrates that carbon capture and storage is not only about technology, but also about documentation. Accurate and verifiable data are essential to meet regulatory requirements and trigger financial support mechanisms. Most important is to ensure public confidence that CO₂ is indeed being permanently removed from the carbon cycle.

More information on measurements in the Longship value chain can be found in this briefing note (.pdf). The note was prepared by Senior Advisors Jale Mutlu and Jan Henry Hansen, both of whom are involved in the follow-up of Longship at Gassnova.