Porthos is developing a project to transport CO₂ from industry in the Port of Rotterdam and store this in empty gas fields under the North Sea. The CO2 will be captured from the facilities of ExxonMobil, Shell, Air Liquide, Air Products and will be supplied to a collective pipeline running through the Rotterdam port area. Porthos will store around 37 Mt CO2, approximately 2.5 Mt CO2 per year for 15 years.