Collecting carbon dioxide from smokestacks and then storing it underground has been identified as an important piece of the puzzle for slowing global warming, and also for Sweden's climate goal of net zero emissions by 2045.
It is not permitted to store carbon dioxide on land today, which is why the SGU agency has investigated an area in the Baltic Sea southeast of Gotland and south of Skåne as part of a government assignment.
SGU estimates that more than 5 million tons of carbon dioxide per year could be stored at the two sites together. This compares to Sweden's total emissions of 47.5 million tons in 2024.
That would roughly correspond to annual emissions from Sweden's shipping. The distribution could then be a slightly smaller portion outside Skåne and a larger portion in the southeastern Baltic Sea, says Sofie Lindström, state geologist and project manager.
The carbon dioxide diffuses into the porous rock, reacting with it over hundreds of years and eventually mineralizing. Above these areas are denser rocks, which hold the molecules in place.
Two proposals were rejected
During SGU's work, new drill cores have been taken outside Trelleborg and on southern Gotland, and surveys have been carried out using ships in the areas. This has been combined with older data.
In the large area off Gotland, three different locations have been investigated. Two of them were ruled out.
It's normal to sometimes find things that aren't as good as you initially thought, says Sofie Lindström.
The third one - called Faluddensandstenen - seems to be working. It should be able to inject 300 million tons of carbon dioxide over 30 years.
It is a very good reservoir rock, says Lindström.
Simulations of the area in the southwest Baltic Sea indicate that the area can store more than 100 million tons of carbon dioxide over the same period.
More tests are needed
There is still a long way to go. SGU needs to carry out further studies. After that, companies that want to store carbon dioxide must apply, be approved and build the infrastructure - drill wells in the seabed and ensure that the carbon dioxide is transported there from ships or possibly from land.
I would guess it will take at least ten years, says Lindström.
CCS stands for carbon capture and storage, that is, the separation and storage of carbon dioxide.
The carbon dioxide is separated from flue gases and compressed under high pressure so that it becomes liquid.
It is then moved via intermediate storage to a permanent storage location one to several kilometers below the seabed and eventually converted into rock.
