One of the measures identified as crucial for us to be able to achieve climate goals and net zero emissions of greenhouse gases by 2045 is the capture and sequestration of carbon dioxide. Many techniques for this exist, with varying levels of maturity. Karin Pettersson, researcher in energy and environmental systems analysis and the person responsible for coordinating RISE’s research into negative emissions, explains the various concepts.
In place since 2017, one of Sweden’s climate goals is to achieve net zero emissions of greenhouse gases by 2045, in order to subsequently achieve negative emissions. The goal means that the country’s greenhouse gas emissions must be reduced by 85 percent compared with 1990 levels. The remaining emissions down to zero, i.e. 15 percent, can be achieved through supplementary measures.
BECCS – paving the way for negative emissions
These supplementary measures include bioenergy with carbon capture and storage (BECCS), which is the capture and storage of carbon dioxide of biogenic origin. This technology has great potential in Sweden, due to a number of large biogenic point-source emissions, mainly from the combustion of biofuels in CHP plants and in the pulp and paper industry.
– “If we are to achieve the 1.5-degree target, it is absolutely crucial that we remove carbon dioxide from the atmosphere,” says Karin Pettersson, researcher at RISE. “BECCS has been identified by the Swedish government as a key technology for achieving zero and negative emissions. Of the approximately 10.7 million tonnes of carbon dioxide to be handled by supplementary measures, BECCS may amount to 10 million tonnes.”
CCS – storage with challenges
Fossil-origin carbon dioxide can also be separated and sequestered. The technique, which is simply referred to as carbon capture and storage (CCS), differs from BECCS based on where the carbon dioxide comes from. The carbon dioxide in BECCS has a non-fossil origin and comes from combusting biomass, but carbon dioxide is also produced from the combustion of fossil fuels, such as coal and oil. Regardless of the source, the carbon dioxide will need to be captured and stored.
– “The storage of carbon dioxide is not without its challenges, and it cannot be done just anywhere,” says Pettersson. “Norway has major initiatives for storing carbon dioxide under the seabed. But the costs of this solution still seem to be rising steadily. In addition, the carbon dioxide must be transported to the storage site.”
If we are to achieve the 1.5-degree target, it is absolutely crucial that we remove carbon dioxide from the atmosphere
CCU – how we can use captured CO2
The possibility exists to use captured carbon dioxide as a potential raw material in new products, a technique referred to as carbon capture and utilisation (CCU).
– “Captured carbon dioxide can be used in several ways,” explains Pettersson. “Either directly in carbonic acid or in greenhouses, for example, or it can be used together with hydrogen to produce electrofuels. As technologies for using captured carbon dioxide evolve, we will most likely see new markets for separated biogenic carbon dioxide, with competition for the CO2 molecules.”
An important aspect concerning the use of captured carbon dioxide is that, although it can contribute to reduced climate impact by replacing a fossil raw material, it does not contribute to negative emissions in the same way as BECCS. Furthermore, the production of electrofuels requires large amounts of electricity.
Carbonation – carbon dioxide storage that creates value
Carbonation is a technology for utilising captured carbon dioxide with great potential, and essentially involves binding CO2 in industrial residual products containing alkali metals. This technique creates products that, among other things, can be used in concrete or as fillers in paint products and pulp and paper products.
– “Carbonation is promising,” asserts Pettersson. “The technique is slightly less efficient, but, at the same time, the costs are lower. It can be used locally, which means less transport, and new products with value on the market are also created.”
How RISE works with captured carbon dioxide
RISE works along the entire CCS/CCU value chain: from separation, purification and reprocessing to the conversion of carbon dioxide into different products, but our efforts in the area also cover several system levels. For example, RISE runs research projects to develop new materials and processes for carbon capture and storage. Next year, several testbeds in the area will be built able to support trade and industry with the development and scaling up of processes and technology. In addition, we work with systems analysis, including techno-economic calculations, life cycle analyses and policy.
– “Regardless of where you are in the system or the industry in which you operate, reducing carbon dioxide emissions is central,” says Pettersson. “And no matter the challenges you face in this regard, here at RISE we can provide advice and support.”
