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Find answers to the most commonly asked carbon removal questions below.

Our technology

  • Neustark’s solution is based on the well-researched chemical process known as natural mineralization or carbonation. Our technology accelerates this process from over 1000 years to just a few hours while multiplying the average CO₂ uptake.

    For more information, see How our solution works.

  • Carbon dioxide mineralization is a process in which CO₂ reacts with alkaline metal to form solid carbonate minerals.

    Demolished concrete aggregate contains hydrated cement phases. These hydrated cement phases are in contact with water, e.g. pore water – and thus in a solid-liquid equilibrium. Part of the hydrated cement is dissolved in the water and therefore present as ions. As CO₂ is also dissolved in this water, new mineral that exhibit lower solubility than the hydrated cement phases precipitate. And voilà, calcium carbonate (CACO3) is formed.

    Thus, the CO₂ and the hydrated cement undergo a chemical transformation to form rock. This so-called carbonation reaction of 1 kg CO₂ releases heat such that the temperature of 1,000 kg of concrete increases by about 2.5°C.

    CACO3 is considered to be amongst the most permanent ways to sequester carbon. Only temperatures above 600°C or very strong acids could trigger the release of CO₂. This ensures that the CO₂ remains stored in the concrete, even if it is demolished again after being reused.

  • The central benefits of storing CO₂ in demolished concrete is that the CO₂ is irreversibly bound to the concrete granules via the mineralization process. The major advantage of this approach over natural carbon sinks (e.g., ocean, trees) is that the embodied carbon in concrete has no chance of returning into the atmosphere. In other words, carbon dioxide is permanently stored inside the concrete.

  • Currently we can store around 10 kg of CO₂ per ton of demolition concrete on an industrial and economical basis – and we’re continuously working on optimizing this figure. Depending on the material characteristics, we can store up to 25 kg of CO₂ per ton.

    In terms of speed, our latest plant stores around 1000 kg of CO₂ per hour in concrete granulate. As a comparison: fast-growing pine trees absorb about 20kg of CO₂ per year . So one neustark plant can do in one hour what 50 trees need a whole year for.

    Or, in other words, within 24 hours, one neustark plant can store the same amount of CO₂ in demolished concrete granulate as the CO₂ that is on average emitted by two single-family homes heating with oil in Switzerland in a year’s time.

    For more information, please see Johannes Tiefenthaler et al’s Technological Demonstration and Life Cycle Assessment of a Negative Emission Value Chain in the Swiss Concrete Sector.

  • No. The mineralization process that is the core of neustark’s technology enables durable CO₂ storage. Permanent means: it is scientifically proven that the fraction of carbon dioxide stored through mineral carbonation that is retained after 1000 years is virtually certain to be 100%. Even if the concrete in which the CO₂ is injected gets demolished again and again, the CO₂ will not be released into the atmosphere.

    There are many negative emission technologies that are in theory, and an increasing amount in practice, viable. They all certainly have their benefits, but mineralization is one of the few technologies that warrants true permanent carbon removal.

  • Durable means: the fraction of carbon dioxide stored through mineral carbonation that is retained after 1000 years is virtually certain to be 100%. The risk of reversal, i.e. that the carbon sequestered is released again into the atmosphere, is negligeable. Even if the concrete in which the CO₂ is injected gets demolished again and again, the CO₂ will not be released into the atmosphere.

    Neustark’s solution is highly permanent, binding CO₂ for thousands to millions of years.

  • Additionality means that the removals in emissions achieved by the project must be “above business as usual". That means they would not have happened unless the project was implemented.

  • Our process does not interfere with natural ecosystems. It requires only a very small area as it is integrated into already existing industrial processes.

  • Neustark’s research & development team is working on optimizing our current technology as well as potential future solutions of permanently storing CO₂.

    We are testing various materials and optimizing our technology operations to increase the average intake of 10kg of CO2 per ton of demolished concrete.

    We are also investigating other related paths of storing CO₂, e.g. in concrete residual water or concrete slurry, and other waste materials.

    On a more long-scale time scope, we are delving into the possibilities of storing CO₂ geologically. Neustark is a leading partner in the research project DemoUpCARMA, led by ETH Zurich, which explores the technical, political and economic scope of storing Swiss CO₂ geologically in Iceland.

Our business model

  • We work with biogas plants to source our CO₂, concrete recyclers to store the CO₂, and companies with ambitious climate strategies that acquire our CDR (carbon dioxide removal).

    In a nutshell: we permanently remove CO₂ and thus generate negative emissions.

  • We have adaptable business models as well as product types, according to your needs.

    In general, neustark constructs the storage technology at your plant. Once finished, the storage site belongs to you, the recycler. An initial, lump-sum investment to purchase the technology is needed. This investment is then counterbalanced by neustark paying you to utilize your storage site. Over the course of a few years, the initial investment is turned into profit for you.

  • Besides making your business (even more) sustainable, creating an additional revenue stream and of course, permanently storing CO₂ the mineralization process holds another big advantage regarding the process of Incinerator Bottom Ash IBA. Harmful substances such as heavy metals are stabilized better within the minerals and contained in the granules through our mineralization, thereby significantly reducing the risk of leaching (accelerated and enhanced weathering).

Our CO₂

  • We partner with biogas plant to filter out the CO₂ that is created during the plant’s production process. We then liquefy the captured CO₂ to then transport it to the nearby storage sites.

  • The CO₂ that we source is biogenic. Biogenic carbon emissions are those that originate from the processing (e.g. combustion, fermentation) of biological materials such as plants and trees. Burning biomass emits carbon that is part of the biogenic carbon cycle (as compared to burning fossil fuels, which releases carbon that has been locked up in the ground for millions of years). In other words, biomass combustion simply returns to the atmosphere the carbon that was absorbed as the plants grew.

    When neustark’s technology injects CO₂ into concrete, it is permanently stored there and removed from where it would otherwise land, in the atmosphere. And since the CO₂ is biogenic, this sequestering process generates negative emissions.

    Neustark’s first source partner is the biogas plant ARA Region Bern in Switzerland. New source sites are currently being built, and further partnerships being evaluated, to ensure a close proximity of our source and storage sites.

  • Today we store around 10 kg of CO₂ per ton of demolished concrete. ​We are of course continuously working on further optimizing this figure.

Our CDR certificates

  • Carbon dioxide removal (CDR), commonly also referred to as carbon removal, is a process that involves extracting carbon dioxide from the atmosphere and harmlessly sequestering (i.e. storing) it in geological, terrestrial, or ocean reservoirs – also known as natural carbon sinks – or by using the CO₂ for another purpose where it is stored permanently.

  • A quality carbon credit means one ton of carbon dioxide has been reduced or removed from the atmosphere. It also means that this reduction or removal has been certified under an internationally recognized carbon standard – such as Gold Standard.

  • The Science-Based Targets Initiative (SBTi), among others, explicitly encourages companies to not only reduce their own footprint but also invest in activities outside of their value chain in the transformation to net zero because of the urgent need to move the dial on climate change mitigation, today.

    Carbon credits are a transparent, measurable and results-based way for companies to do so.

    A quality carbon credit means one ton of carbon dioxide has been reduced or removed from the atmosphere. It also means that this reduction or removal has been certified under an internationally recognized carbon standard – such as Gold Standard.

    There’s an increasing call for companies to – next to their own vigorous reduction efforts – invest in carbon removal credits to cover their unavoided emissions.

    Complement your company’s drastic emissions reductions with neustark’s carbon dioxide removal (CDR) service.

  • Current research shows that there is no single solution that could be deployed at scale to remove hundreds of gigatons of CO₂ from the atmosphere by the end of this century.

    Some proposals for carbon removal are at a very early stage in their development, others are more established. They vary in cost, how much they can remove and in the resources they require (such as land, water and energy). Some carry risks, for instance due to costs of land conversion and biodiversity loss, particularly if deployed on very large scales. Some bring co-benefits, for instance generating power, reversing biodiversity loss or providing useful materials. Some may prove unsuccessful in scaling up. Importantly, there is still much scope for innovation and improvement, and some techniques will work better in some contexts than others.

    The answer is in the mix – and with a focus on solutions that have been proven both ecologically and economically feasible and can make a significant impact in the next decade.

  • Neustark sources CO₂ from biogas production sites and stores it in demolished concrete permanently.

    The CO₂ sourced from the biogas sites is biogenic CO₂, i.e. if released into the atmosphere by the biogas plants, the process would be carbon-neutral (as the plants combusted in the process already absorbed CO₂ earlier in their life cycle).

    By capturing and storing this biogenic CO₂, neustark removes carbon-neutral emissions that would otherwise have gone into the atmosphere – hence creating negative emissions.

  • The amount of CDR we will need depends on our choices: how much we choose to limit the rise in global temperature, how much we choose to reduce emissions, and in which timeframe.

    The Special Report on 1.5°C by the IPCC underlines that pathways that limit global warming to 1.5°C will require carbon and other GHG removal on the order of 100–1000 billion tons of CO₂ over the 21st century.

    See chart below: Necessary order of magnitude for carbon removal for emission path of 1.5°C (data source: Network for Greening the Financial System Scenario Explorer. Model: REMIND-MAgPIE 1.7-3.0; provided by IIASA).

    Statistic carbon removal
  • If your business has set SBTi targets, you will need to make the transition to carbon removal credits by 2030.

    By starting the process now, you can secure your business’ ability to meet your sustainability targets while leading the way for everyone else.

    Even if your company hasn’t set SBTi targets, the interest from consumers and investors in sustainability will only continue to grow – as will potentially compliance requirements. Carbon removal credits are a tool for decarbonization that can pair with other carbon reduction efforts.

    It’s important to reduce what you can and source high quality carbon credits to reach your climate goals.

  • There are a plethora of carbon removal technologies currently being developed or deployed in practice. Methods ranging from direct air capture (DAC) and bioenergy with carbon capture and storage (BECCS) to afforestation and biochar all have unique characteristics in terms of cost, technology maturity, permanence and risk of reversal.

    It’s important to have a 360-degree approach when setting your climate strategy and risks should always be investigated and addressed through a thorough due diligence process.

    You should be mindful about methods that have a higher risk of reversal, less transparent measurement methods, or little proof of concept.

  • While all types of carbon credits are important tools in helping to achieve a net zero future, the technical differences between carbon removal credits and other carbon credits are important to note.

    Carbon avoidance projects contribute to climate action by preventing carbon that would have been released into the atmosphere. This could be building a wind farm to lower reliance on fossil fuels or preventing deforestation.

    In buying carbon offsets, a company invests in reducing their emissions via an external project.

    Carbon removal projects, as the name suggests, remove carbon from the atmosphere – thus creating negative emissions. Broadly speaking, they are split into 2 categories: natural carbon removals, like tree planting which sequesters carbon as the trees grow, and technological carbon removals, for example, point source CO2 capture and storage via mineralization, like neustark does.

    In investing in carbon removal credits, a company counterbalances their hard to abate emissions – in additional to own drastic emission reductions.

  • CDR removes carbon from the atmosphere, thus removing previous emissions – enabling us to address both unavoidable and historic emissions.

    CCS prevents carbon from entering the atmosphere – making it a concept that focuses on reducing emissions.

  • There are a number of reasons prices of carbon credits vary, for instance:

    • the quality of carbon removal a company offers, including factors such as permanence, measurability and rapid delivery;
    • varying implementation costs depending on the size and location of a project;
    • similarly some types of technology are more expensive than others, though prices will be driven down by scaling up in the next years;
    • carbon pricing regulations can affect prices in the voluntary carbon markets too;
    • finally, prices are driven to a large extent by supply and demand.
  • There are a number of carbon removal or negative emissions technologies (NET) that can use biological or technological approaches to remove CO₂ from the atmosphere and store it on a more or less permanent basis.

    Essentially, CO₂ can be captured in biomass (through photosynthesis) or by chemical means (using air filters or mineral sequestration). The CO₂ is then stored in biomass on the earth's surface (e.g. in wood), in the soil, in the geological substrate, in minerals or in the seabed.

    For these technologies to generate negative emissions to a degree that affects the climate, the CO₂ must be stored for a long time, preferably for thousands if not millions of years.

    CO₂ stored in forest biomass or in humus in the soil is more liable to end up back in the air than CO₂ sequestered deep underground or in minerals, due for example to exceptional events (such as forest fires) or intensive soil tillage.

    There is a need to shift to technology-based removal while maintaining historical nature-based carbon sinks. Why? Because nature-based sequestration has its limitations in permanence as well as capacity. There is a clear need for additional tech-based removal, the potential of which is abundant.

    For more information, see Swiss Federal Office for the Environment’s classification: factsheet.