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CCUS, which stands for Carbon Capture, Utilization and Storage, indicates the set of technologies used to capture CO2 and store it in the oceans or other natural reservoirs, preventing it from being released into the air when it is emitted and therefore pollutes. According to the IEA (International Energy Agency), it is an essential tool for the implementation of decarbonization. The ocean is the largest carbon sink on the planet, a natural system that absorbs excess carbon dioxide from the atmosphere and stores it. About 25-30% of CO2 emitted into the atmosphere throughout the industrial era has been absorbed by the ocean (source: External Forcing Explains Recent Decadal Variability of the Ocean Carbon Sink, Columbia University). Today, thanks to technology, what is a natural process can be artificially reproduced by humans, for the environmental purpose of achieving the increasingly pressing net zero goals.
Capturing and storing CO2
If the technologies that are used to make it are different, the basic idea is unique and simple: you capture the CO2, directly at the source, then from the industries that generate it in the production process and if it is not reused on site, the captured CO2 is compressed and transported by pipeline, ship, rail or road to be either injected into deep geological formations such as spent oil and gas reservoirs or saline aquifers or used in a range of applications. For example, as a feedstock in the production of synthetic fuels such as methanol or synthetic diesel through chemical synthesis processes; to carbonate cement during the production process, transforming it into a more resistant and sustainable material; to produce polymers, plastics, and building materials; in agriculture to increase crop yields through the process of fertilizing plants; in the food industry to carbonate beverages such as carbonated soft drinks and mineral water; as a raw material for the production of various chemicals, such as acids, solvents and fertilizers. These are just a few examples: developments in research and innovation to find new effective and efficient ways to use this gas are continuous. It is a sustainable way of decarbonizing for a number of reasons that the IEA itself identifies: it is an effective system for reducing emissions in hard-to-abate sectors, such as cement, steel or chemicals. It is a facilitator of low-cost, low-carbon hydrogen production, useful for the decarbonisation of industries, but also of road and ship transport. In addition, it can be built in old power generation and industrial plants, which are not decommissioned but continue to operate. Today, there are around 500 active projects in various stages of development along the entire CCUS value chain and around 40 plants are in operation worldwide, with a total annual capacity of more than 45 Mt CO2. More than 50 new capture facilities have been announced that aim to be operational by 2030, which is about a third of what is required to implement net zero by that date.
The role of the oceans
In this evolution of the concept of CCUS, startups play an important role and many are already participating in this climate challenge, including those operating on the sea front. CO2 is absorbed by nature in a variety of ways: for example, it is captured by rain and then binds with limestone when it falls back to the ground. It turns into calcium bicarbonate and ends up in the sea. However, this natural process is being altered due to the increase in CO2 in the atmosphere that acidifies the oceans, reducing the share of carbonate ions, including bicarbonates, present in the water. So, in theory, it wouldn’t seem like a good idea to inject more and more CO2 into the ocean floor because it has harmful side effects on underwater life and is, along with temperature, the main culprit for coral reef erosion. Therefore, while CO2 is absorbed in the sea, strategies have always been developed to minimize water acidification. The most commonly used methods are enhanced weathering, ocean alkalinity enhancement and electrochemical ocean CO2 capture. The first two strategies are based on introducing finely crushed alkaline rocks into the ocean in order to increase its buffering capacity to absorb carbon dioxide. The third is based on acid-base separation and electrochemical CO2 removal techniques and generally allows the creation of other by-products with energy consumption. But there is a need to evolve research because all the methods currently in use to avoid ocean acidification are based on chemical processes that require a high expenditure of energy or carry the risk of releasing toxic substances.
What Startups Do
Based on existing technologies and the need to improve them, leading startups in the sector are coming up with new ideas to make CO2 absorption in the oceans more efficient and sustainable. Most startups in this sector were born in the United States or Canada due to increased availability of funding. In Italy there is Limenet. Among them are: Planetary is a Canadian startup founded in 2019 with the aim of increasing the alkalinity of the ocean through the introduction of magnesium hydroxide. The introduction of this substance increases the CO2 capture capacity of the ocean, but the pH increases if the hydroxide is not completely dissolved. The funding received allowed it to raise a total of $8.6 million total. CarbonRun is a Canadian startup founded in 2022 that has studied an original process. Also in this case the idea is to increase alkalinity: starting from the dissolution of alkaline rocks, such as calcium carbonate and dolomite, directly into rivers damaged by acid rain or pollution. This captures terrestrial carbon released from the ground into rivers and atmospheric carbon from the air. The dissolution process can be time-consuming and is not controlled once the release of the carbonates has taken place. Ebb Carbon, founded in 2021 and headquartered in California, has received $29 million in funding to further study the proprietary process of separating acidic and basic parts of ocean water through the use of ion-selective membranes. The acidic part is extracted and accumulated for other uses, while the basic part is reintroduced into the ocean. The introduction of a basic substance into the water must be done in an extremely controlled manner to avoid too high an increase in pH. Equatic, a U.S. company founded in 2018, has received $30 million in funding to develop a CO2 reduction system based on electrolysis, the separation of solutions that is achieved by applying an electric field between two electrodes, of seawater. The chemical reaction that takes place also allows the production of hydrogen. In Europe, there is the Italian company Limenet, which has developed a unique technology in this area. Limenet focuses on CO2 capture and permanent storage in the form of calcium bicarbonates, through pH-balanced ocean alkalinity enhancement. It is a system that is based on the monitored industrialization of the geological carbon cycle. It reverses the process of ocean acidification, turning CO2 into calcium bicarbonate with pH control, thereby reducing CO2 in the atmosphere and contributing to the preservation of the oceans. The process is one of the only ones in the world that allows carbon to remain in the ocean in a stable form for tens of thousands of years. In addition, the injection of bicarbonates into the sea makes it possible to stop the decrease in pH thanks to the buffering effect of the alkalinity introduced due to high CO2 concentrations. We have an extremely high storage potential, in the hundreds of gigatonnes, thanks to the use of raw materials that are easily available in almost every place in the world. Calcium carbonate accounts for 7% of the earth’s crust. The study of technologies related to ocean alkalinity enhancement has been growing exponentially in recent years. In fact, it is being discovered how, in a simple and fast way, it is possible to permanently store CO2 at the bottom of the sea, counteracting not only the increase in CO2 in the atmosphere but also reducing the acidification of the seas itself due to this climate-altering gas. Limenet, which is a benefit corporation and has patented an innovative technology to remove and permanently store carbon dioxide for a period of more than 10 thousand years, storing it in the sea in the form of calcium bicarbonates in seawater, is founded by Stefano Cappello (CEO), engineer and researcher, together with Giovanni Cappello (CTO) and Enrico Noseda, former co-founder of startups such as HLPY and chief innovation advisor of Cariplo Factory. (Photo by Cristian Palmer on Unsplash)
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