Modular carbon capture tech slashes cargo ship CO2 emissions by 70%

The air at sea might be getting a bit cleaner as technology group Wärtsilä puts its Carbon Capture Solution (CCS) system on the market. The modular apparatus is claimed to capture as much as 70% of the CO₂ emissions from cargo ship exhaust systems.

Whether because of environmental concerns or a self-interest in economic survival, shipping companies are showing an increasing interest in new ways of reducing their carbon emissions. In 2022, cargo ships accounted for 858 million tonnes of carbon dioxide emissions, with lager ships making up 79% of that figure. On the whole, the shipping sector is estimated to produce up to 3% of all anthropogenic CO₂ emissions and with the International Maritime Organization (IMO) is aiming at a net-zero target by 2050. With fines after that date of up to US$380 per tonne of unsanctioned carbon, emission reduction technologies are drawing a lot of attention these days.

Since 2019, Wärtsilä has been developing its CCS system for recovering CO₂ from the exhausts of cargo ships burning all manner of fuels. The technology itself isn't new. The various bits and bobs that make it up have been used by the gas, oil, and chemical industries for decades, but converting it into a modular system that is scalable and can be both fitted into new ships and retrofitted into existing ones is certainly worth sitting up and taking notice of. In addition, its modular design means that it can be easily modified to suit ships that already have exhaust scrubbing systems.

The CCS is essentially a five-stage process. First, the exhaust gas from the ship's engines is cleaned of particulate matter like soot and pollutants like nitrogen oxides and sulfur oxides. After cleaning and cooling, the exhaust then goes into an absorption chamber where a liquid amine solvent absorbs the CO₂. Exactly what this solvent is remains proprietary information, but it's likely some variant on monoethanolamine (MEA), diethanolamine (DEA), and piperazine-based blends.

Once absorption is completed, the solvent moves to a stripping chamber, where it is heated. This releases the CO₂ as a gas. This is compressed, dried, and cooled until it liquefies. It's then stored in onboard tanks for later offloading in port.

According to the company, this process can recover as much as 70% of the CO₂. Exactly how much this costs is unclear, but estimates place it at between €50 to €70 (US$54 to $76) – a lot cheaper than the future fines. If the technology plays out and is adopted worldwide, it could reduce emissions by up to 700 million tonnes per year.

The CCS system was installed in the Solvang ASA 21,000-m³ (741,609-ft³) capacity ethylene carrier Clipper Eris, which has been testing the full installation since February 2025 when it sailed from Singapore. During these tests, the CSS was able to process 50 tonnes of CO₂ per day from the engines burning heavy fuel oil – an economical, but rather dirty fossil fuel.

"CCS is a game-changer for the maritime industry, and we are already seeing huge interest in the market for this solution," said Håkan Agnevall, President and CEO of Wärtsilä. "Ahead of shipping’s net-zero targets, this new technology complements the industry’s ongoing efforts to dramatically reduce emissions from vessels and prevent stranded assets.

"Collaboration has been key here. To achieve this significant advance in maritime emissions control it is important to be able to cooperate with like-minded partners such as Solvang ASA. We congratulate them for their vision and support in bringing CCS to their fleet."

Source: Wärtsilä