Norway has led the way in carbon capture and storage (CCS) for many years, underpinned by its leading role in oil and gas production in the Norwegian, Barents and North Seas over the past half century, but there has been significant recent CCS activity in Denmark, Iceland and Sweden too. In the past couple of years, a critical mass of activity and collective will may have been reached, suggesting that the mass rollout of CCS will happen in the coming years.
At least seven CO2 storage sites are now either in operation or being evaluated. Hard-to-decarbonise industries are looking at capturing their emissions and utilising networks and hubs to share efficiencies for dehydration, compression, intermediate storage and transport to sequestration sites. Power-to-X, Energy-from- Waste (EfW), District Heating and Hybrid Energy Solutions are all big topics of discussion, supported by Scandinavia’s abundant and continuously expanding renewable energy sector.
Efforts are being made to actively decarbonise industrial emissions by removing legislative and commercial hurdles, whilst simultaneously utilising a highly experienced offshore workforce, specialised academic centres of excellence and the current political will to implement change. Given the modest scale of their emissions compared to their more populous European neighbours, and some favourable geology, it is likely that the Danish, Norwegian and even Icelandic storage sites will be able to provide ‘storage as a service’ in the not-too-distant future.
Norway Leads the Way
The Sleipner project was the world’s first commercial CO2 project, originally motivated by the implementation of a CO2 tax in Norway. Since Statoil brought the facility online in 1996, more than 18 million tonnes of CO2 have been injected to a depth 800–1000m into the saline aquifers of the Utsira Formation. Capturing the CO2 emitted from the natural gas production (up to 9%), it is reinjected on location.
This development was followed in 2008 by the Equinor-operated Snøhvit project, this time driven by both regulatory requirements and a carbon tax. The CCS-equipped LNG processing plant on Melkoya island, near Hammerfest, strips the 5–8% CO2 piped ashore from the Snøhvit field in the Barents Sea. Up to 0.7 million tonnes per year (Mtpa) are captured and sent back offshore, via a 150 km pipeline, and sequestered within the saline Tubasan Formation, some 2.6 km below the seabed.
Recently, there has been a lot of focus on the development of open access, full value chain projects and networks. The Langskib (Longship) project is a full-scale CCS project designed to capture CO2 from industrial polluters in onshore Norway and beyond. Industrial emissions will be captured at the Heidelberg Cement’s Norcem cement factory in Brevik and Fortum Oslo Varme’s waste incineration facility in Oslo Fjord. Ships will transport the CO2 to an onshore terminal on the Norwegian coast, before it is piped offshore and then stored in the Cook and Johansen Formations, some 2.5 km below the Norwegian Sea. The transport and storage elements of this project are called Northern Lights and start-up is expected in 2023–2024. With imports from additional emission sources, this will increase to c. 1.5 Mtpa then potentially 5 Mtpa.
Horisont Energi, Equinor and Vår Energi have very recently been awarded a CO2 storage licence for a site in the Barents Sea with storage capacity in excess of 100 Mt. The Polaris CCS project is being matured off the coast of Finnmark and is linked to the Barents Blue project, which will be Europe’s first world-scale carbon-neutral ammonia production plant. Natural gas will be converted into blue ammonia, with CO2 being stored in the Polaris reservoir.
Denmark’s Use of Depleted Oil and Gas Fields
Denmark has proven subsurface storage potential. With the fall in oil and gas production in the offshore Danish sector, the country has been advancing its plans to repurpose its oil and gas fields and infrastructure for carbon sequestration. Oil production is now less than 70,000 bopd in the country, with gas at around 135 MMscfd. With their significant and well-described storage capacity, along with decades of understanding of the subsurface performance, many see a distinct advantage to using oil and gas assets for CO2 storage over saline aquifers.
There are benefits to using existing infrastructure too, including the deferral of some abandonment liabilities and the acceleration of the timeline to first sequestration.
Offshore locations are deemed to be less contentious with the public at present, although potential structures closer to shore have been identified. The counter argument to the use of depleted oil and gas fields is primarily around storage capacity and efficiency, as well as the potential for the legacy well stock to act as leak points.
There are two major sequestration projects currently in the planning stages. The first, Project Greensand, is a consortium led by INEOS, in partnership with 22 other companies including Wintershall Dea, Maersk Drilling and Geological Survey of Denmark and Greenland (GEUS). The strategy is centred around the depleted Siri area oil fields on the border between Norway and Denmark, in the Permian Basin, and the plan to store carbon dioxide in these assets. The project is named after the distinctive colour of the target for CO2 injection – the green-coloured, glauconitic Tertiary sands that originate from the Stavanger Platform in Norway and are present throughout the region.
The partnership is estimating in the region of 4–8 Mtpa storage potential in the wider Siri area, primarily into the old oil fields at depths of up to 2 km. The project aims will begin with a pilot phase before first ramping up in 2023 to a demonstration then to a full-scale development beyond Nini in 2025 (3–4 Mtpa). Shuttle tankers will offload CO2 captured at onshore industrial facilities.
The second sequestration project is called Bifrost and is a partnership of the Danish Underground Consortium (DUC), Ørsted and DTU. This group are evaluating the potential for CO2 transport and storage at the Harald field in the Danish North Sea, with a start-up capacity of 3 Mtpa. Initially, Harald West will be utilised, with its sandstone reservoir targeted for first sequestration in 2027. To achieve the scalability and longevity, there is however a need to unlock the chalk storage potential, starting with Harald East. Research in this area is ongoing.
In Copenhagen, there is a focus on making the Danish capital the world’s first carbon neutral capital city. This is led by C4 (Carbon Capture Cluster Copenhagen) which brings together large industrial power producers who are now collaborating on shared infrastructure and storage options. Whilst the country leads the world in renewable energy deployment, Denmark produces some of the highest levels of municipal waste (per capita) in the European Union and has a long history of burning that material. Recovering the energy from waste, capturing the CO2 emissions and storing the CO2 in repurposed offshore assets seems like a great example of the circular economy in action.
The largest project to date is led by Amager Resource Centre (ARC), the owner of the Amager Bakke Waste-to-Energy plant. Its facility supplies low-carbon electricity to over 500,000 people and district heating to 140,000 households. They plan to capture 0.5 Mtpa, helping the municipality of Copenhagen to become carbon neutral by 2025.
The Amager Bakke Waste-to-Energy facility opened in 2017 and is playing a key role in the circular economy. It is a combined heat and power complex and one of the largest waste-to-energy (WtE) projects in northern Europe. Owned by the local municipalities, it incinerates 450,000 tonnes of residential and commercial waste each year, generating steam at 440⁰C / 70 bar. This energy is recovered for households in the surrounding area, supplying both district heating and power. Between 0–60 MW electricity and 157–247 MW district heating are generated, dependent on local demand and power prices. WtE will become a big industry in the coming years.
A pilot CO2 capture project has been kicked off at the site, with the ultimate aim of being upscaled to capture and store 90–95% of the 500,000 tonnes of CO2 emissions annually emitted by the new facility. The captured CO2 will be liquefied and transported by pipeline to the terminal on nearby Prøvestenen. From there, it can be shipped to several possible depleted oil and gas field sequestration sites under development in the Danish offshore.
Iceland Leverages its Geology
85% of Iceland’s primary energy is derived from renewables. Electricity is almost entirely generated from a mix of hydropower (c. 70%) and geothermal (c. 30%). Geothermal has been used for industrial purposes in Iceland for decades. Recently, the abundance of renewable energy is behind a push for Power-to-X, Green Hydrogen and other eFuels. And the abundant basalt could store large volumes of CO2 meaning that carbon sequestration is making progress too.
Geothermal wells can have greenhouse gas emissions (GHG) too. Landsvirkjun’s newest geothermal power plant, Þeistareykir, is located in north-east Iceland. With an installed capacity of 90 MW, it emits around 6.5 kilotons of CO2 per year. Project ‘Koldis’ aims to reduce CO2 emissions by over 90% by capturing emissions and reinjecting on site. The plant is expected to be onstream by 2025.
Climeworks have collocated their facility with the Hellisheidi geothermal plant. Orca is the world’s first large-scale direct air capture (DAC) and storage facility, with plans to expand to 0.5 Mtpa by 2030. Geothermal is used to power fans, filters and heaters. The DAC CO2 is reinjected into the subsurface onsite at Carbfix’s mineral storage facility, along with CO2 and H2S emissions from Hellisheidi.
Carbfix are also constructing the Coda terminal at Straumsvik. CO2 shipments from across northern Europe will be able to dispatch to the terminal. CO2 is then dissolved in water before being injected into highly reactive basaltic rock. Within two years, much of the CO2 will have formed solid carbonate minerals, permanently and safely locking it away.
Sweden Focuses on Capture
With a population greater than that of Norway, Denmark and Iceland combined, there is significant emissions capture potential in Sweden. Although the industrial emitters tend to be small and far apart, they are mainly present on the east coast of the country, allowing for potential evacuation by ship.
Most of the country is underlain by Precambrian craton (crystalline basement rock), which poses a significant challenge to finding suitable sites for CO2 sequestration within the country itself. There are small sedimentary basins close to the Danish border in the county of Skåne in the south-west of the country, as well as in the southern portion of the Baltic Sea, and some research is ongoing to examine the potential for sequestration within fractured basement. However, it seems likely that Swedish hard-to-decarbonise industries will initially look to export captured carbon eastwards to Norway, Denmark and the UK.
Activity, therefore, is focused on capture and intermediate storage, rather than the development of long-term sequestration sites. By way of example, the CinfraCap project (Carbon Infrastructure Capture) is focused on the cost-effective transport of CO2. It is examining ways of improving efficiencies in the logistics chain: liquefaction, intermediate storage etc. Göteborg Energi, Nordion Energi, Preem and several other industrial facility owners in western Sweden are participating in this research.
The Preem project is a test facility that commenced operations in 2020. It aims to capture CO2 from flue gases from Preem’s hydrogen gas plant at the Lysekil refinery. This project is being carried out in collaboration with Aker Solutions, Chalmers University of Technology, Equinor and the Norwegian research institute SINTEF. Funding support is coming from the Swedish Energy Agency and a Norwegian research programme called CLIMIT. Initially 0.5 Mtpa are being targeted; however the combined emissions of the Lysekil and Gothenburg refineries are c. 2 Mtpa. It seems likely the Norwegian Northern Lights could be the destination for the captured CO2.
Slite Cement is a factory on the island of Götland, owned by Heidelberg Cement. It aims to be the world’s first carbon neutral cement works and is targeting the capture of all 1.8 Mtpa of CO2 emissions. Heidelberg are already working on the Brevik site in Norway, working to capture emissions with Aker Carbon Capture, as part of the Northern Lights project. The municipal energy company Stockholm Exergi has installed a test facility at the Värtaverket bio-cogeneration plant in Stockholm. The project is looking at bioenergy with CCS (BECCS) and has the potential to capture 800 ktpa.
David Pickering – Pickering Geoscience
