CarbonCycleCultureClub (C4):
“Closing the Loop / Carbon Credits / Carbon Pricing”

Trading in CO₂ certificates is already a powerful market today. For example, the FAZ wrote on November 8, 2024: “In 2022, 1.9 billion dollars flowed into this CO₂ market. This money was used to offset 254 million tons of CO₂.” How will the CO₂ certificate market develop and what can the proceeds be used for?

On Thursday, November 28, 2024, the topic of the C4 was: “Closing the Loop / Carbon Credits / Carbon Pricing”. In the Great Hall of the Städtisches Kulturhaus Bitterfeld-Wolfen, the possible merging of the European and global carbon markets was discussed, among other things. The event was moderated by Professor Ralf Wehrspohn, Chairman of the Board of Forum Rathenau.

CO₂ is unpopular. Industry, for example, needs to get rid of it in order to achieve climate protection targets. One way to do this is through CO₂ markets. This turns CO₂ into a commodity and makes it attractive for others. It brings money. For example, for reforestation projects or technologies that store CO₂ in the long term.

The CO₂ markets played an important role at the UN Climate Change Conference in Baku. At the start, Federal Minister for Economic Affairs and Climate Protection Robert Habeck (Greens) called for an expansion of CO₂ pricing in the EU and worldwide. The Vice-Chancellor justified this with the very positive experiences that have been made with EU emissions trading for the energy and industry sectors.

Professor Wehrspohn and the keynote speaker at the C4 event, Professor Andreas Löschel, one of Germany’s best-known environmental economists and an acatech member, were also present at COP29 in Azerbaijan. The holder of the Chair of Environmental/Resource Economics and Sustainability at Ruhr University Bochum reported on the latest results of COP29 in Baku and explained what they mean for the CO₂ markets; the European trading market (EU Emissions Trading System (EU ETS)) and the voluntary global CO₂ market, which is developing dynamically and is currently achieving higher prices than the European Union’s CO₂ market.

Guests on the panel were:

Professor Dr. Andreas Löschel, acatech member, holder of the Chair of Environmental/Resource Economics and Sustainability, Ruhr University Bochum (hybrid)

Dr Maria Gaudig, Deputy Head of the Hydrogen Group ITEL - German Lithium Institute, Postdoc Institute of Physics, Martin Luther University Halle-Wittenberg

Dr Sebastian Kunz, Senior Manager Catalysis and Carbohydrate Chemistry, Südzucker AG, Central Department Research, Development, Services CRDS (hybrid)

Professor Georg Locher, Schwenk Building Materials Group

CO₂ certificates, which are currently available on the European trading market (EU Emissions Trading System (EU ETS)), are traded on an exchange. They apply to different sectors such as mobility, European aviation and industry. Each year, a fixed number of certificates are issued by the European Union. Companies can purchase them in order to emit CO₂.

The principle behind it: there are fewer certificates every year. Scarcity influences the price of CO₂ emissions. Industry and customers can either pay a higher price or reduce CO₂ emissions.

“This certificate system is the best instrument in the field of environmental economics,” says Professor Ralf Wehrspohn. “It is better than a fixed CO₂ price and better than a tax.” This is because the target function (in 2045, the European Union wants to have zero certificates) will definitely achieve the goal. And the path to the target strengthens precisely those measures that help reduce CO₂ emissions most economically.

This European Emissions Trading System only applies to Europe so far. A second certification system has developed worldwide. This global certification system from the field of green finance means that if an entrepreneur goes to the bank today and wants financing, they must present a sustainability strategy. Or the company has to buy negative CO₂ certificates.

This works in the same way as for private individuals who want to reduce their carbon footprint when taking a flight or ordering from a delivery service. This does not change the CO₂ emissions, but the company has to buy negative emissions. So the same amount of CO₂ is stored elsewhere. This is the voluntary CO₂ market.

The trading platforms that have developed worldwide store CO₂ in biomass, for example, such as in mangrove forests or in seagrass. Blue carbon is an example of this, but CO₂ is also stored underground in caverns, in rock formations such as in Iceland, where CO₂ is bound underground and mineralized. CO₂ can also be converted into biochar for soil improvement and water retention or bound in peatlands. So are agriculture and nature conservation the new beneficiaries of a CO₂ market?

Negative emissions are not zero emissions. For negative emissions, the CO₂ must be actively extracted from the air and sequestered in the long term. Carbon is stored in the long term, for example by being transformed into rock or by being bound in humus or in mangrove forests or seagrass as well as in timber construction. It is only through long-term sequestration that we speak of negative emissions.

This voluntary market is currently developing dynamically worldwide and is achieving higher prices than the European Union‘s CO₂ market. This was discussed in C4: Can both markets, the mandatory European market and the global voluntary market, come together? One working hypothesis that we discussed in the C4: Can the voluntary CO₂ market be the key to global climate neutrality?

The other model is the climate club model initiated by German Chancellor Olaf Scholz. It means that the EU ETS market, i.e. the mandatory market, is extended to as many countries as possible. This is supplemented by the Carbon Border Adjustment Mechanism (CBAM).

The question on 28 November 2024 in the C4 was therefore: Can the European, state-organized CO₂ market be linked to the international voluntary markets? There is still a lack of CO₂ storage technologies. There are options, but which are ready for the market? This was discussed based on possible market designs to see which new ideas lead to the future.

The cement industry and CO₂

Professor Georg Locher reported that his industry, the cement industry, is blessed with carbon: “We have so much of it that we would like to give it to others. Unfortunately, we have it in the form of CO₂.” The CO₂ comes primarily from limestone, but he began his short presentation with some positive news. The Schwenk Building Materials Group is currently in the process of testing a new CO₂ separation technology that is specially tailored to the cement industry in one of its plants. The corresponding research and test facility is currently under construction. It will cost € 120 million, which will be invested jointly with three market players. Public funding is not being used “because we attach particular importance to speed,” said Professor Locher.

He explained: “First and foremost, our CO₂ comes from limestone. This means that to produce cement, you have to heat limestone very, very strongly to over 800 °C.” For the entire process, 1450 °C must be reached, but at over 850 °C, the CO₂ escapes from the limestone and goes into the atmosphere. This accounts for the lion’s share of emissions in the process. This affects the entire cement industry. Two thirds of the emissions come from the limestone, for example, with the remainder coming from combustion.

Locher: “At Schwenk, we are particularly proud of the fact that we can rely entirely on secondary fuels for these thermal energy sources. So we don‘t need any fossil fuels.”

In terms of CO₂, however, there are currently some challenges in practical implementation. In purely mathematical terms, 25 wind turbines (average German wind turbines) are needed to operate a normal cement plant. Of course, this is not possible in practice, as storage facilities, batteries, etc. would have to be available. Another 100 wind turbines would be needed to capture CO₂, which is extremely energy-intensive. A large proportion of these would be needed to compress the CO₂.

This means that it would either have to be compressed to over 100 bar so that it can be transported through a pipeline or, because no CO₂ pipeline will be available in the near future, it would have to be cooled down to -30 °C. It then becomes liquid and can be filled into large tank wagons. This is also extremely energy-intensive.

An average German cement plant would need around two whole trains of such tank wagons every day. This would fit around 60 t of deep-frozen, liquid CO₂. It would then be possible, for example, to make methanol or sustainable aviation fuels, artificial kerosene for air traffic, among other things. However, this would require an additional 300 t of green hydrogen per day – 100000 t/a. “Is that a lot?” Locher asked and noted: The port of Rotterdam is the largest energy-importing port in Europe. The plan there is to import around one million tons of hydrogen in 2030. However, these one million tons are not planned for the cement industry alone, but Professor Locher said that he assumes that the chemical industry is being considered first and foremost.

“That‘s a hell of a lot of what we need,” said Locher. “That‘s why we are of course urgently waiting for the hydrogen network.” Annoyingly, however, this will not be ready until 2032 as things stand. However, Schwenk is planning to start in 2030. The hydrogen could of course also be transported to the plant by rail.

However, a container like the one offered by Deutsche Bahn, for example, only holds 1.3 t. For 300 t to be transported to the cement plant every day, over 200 wagons would be needed. This is therefore unrealistic.

The alternative of working on site with electrolysers is also difficult, as this would require 600 individual electrolysers in the one-megawatt class. These are commonly used at present. You could also build larger ones, four megawatts for example. But that would still require 150 plus 750 additional wind turbines just to provide the necessary hydrogen.

Then there is the European legislation, which stipulates exactly what green hydrogen is. The so-called Delegated Act stipulates that the wind turbines and electrolysers must be built from scratch. And the last point is, according to Locher: “They all have to operate at the same time. That is the simultaneity rule. At this point at the latest, we have said: This is a wonderful project for the future. But unfortunately we can’t implement it in practice at the moment.”

Locher summarized that Schwenk can therefore only focus on storing CO₂ at the moment. According to the studies of the Intergovernmental Panel on Climate Change (IPCC) and the corresponding scenarios regarding compliance with a 1.5 °C or 2 °C climate target, it is clear how much CO₂ will have to be stored in the future in order to achieve the climate targets. “We’re talking about many hundreds of gigatons,” says Locher. By comparison, Germany emits less than 1 Gt/a in total. “But the IPCC says we need to remove several hundred gigatons from the atmosphere,” says Locher. “So I would say that CO₂ storage is a technology that the IPCC is also backing heavily. And so, of course, we also see ourselves in this position with the corresponding backing of the IPCC.”

“This raises many questions,” commented moderator Professor Wehrspohn on Professor Locher’s contribution. Is CO₂ storage really the only option? What does the Intergovernmental Panel on Climate Change think? Does the CO₂ molecule really have to be physically transported from the cement plant to the cavern in Norway or can it also be a balance sheet option?

The risks of a CCS ban are greater than the risks of CCS

Professor Andreas Löschel, acatech member and holder of the Chair of Environmental/Resource Economics and Sustainability at Ruhr University Bochum, had already spoken in the C4 on December 16, 2021 about the IPCC scenarios, which he first wrote down as a lead author in 2014. This was the first time it became clear: “Without negative emissions, none of this will work,” said Professor Löschel. The 2-degree target would be very difficult to achieve and reaching the 1.5-degree target would be impossible. With regard to Professor Locher’s contribution, he said: “I think we are going in the wrong direction, if I may say so, also with regard to the Delegates’ Act. The aim cannot be to prevent these options, but we must enable them and scale them up relatively quickly, otherwise we will have a major problem.”

His keynote speech referred to the work in the context of the academies’ project Energy Systems of the Future (ESYS) “Integrated thinking on carbon management”, where he has been Chairman of the Board of Directors since the beginning of the year, an initiative of the German Academies of Sciences Leopoldina, the National Academy of Sciences, acatech, the German Academy of Science and Engineering and the Union of the German Academies of Sciences and Humanities. According to Löschel, carbon management and the challenges for an overall strategy that brings together the various building blocks were also discussed as part of this.

In particular, the document builds on the first drafts of the carbon management strategy (CMS) and long-term strategy for negative emissions (LNe). Despite the further development, the fundamental issues are still present and need to be resolved. The two documents addressed different areas, but also overlapped. In the context of the first area, the carbon management strategy, the focus is on how to deal with emissions that are difficult to avoid, particularly in the industrial and waste management sectors, and what unavoidable residual emissions are.

The long-term strategy should focus on how greenhouse gas emissions can be offset from residual emissions. The function of CCS (Carbon Capture and Storage) / CCU (Carbon Capture and Utilization) removals changed somewhat over time. “In the last IPCC report in the energy chapter, we tried to work out how the system also changes somewhat over time,” Löschel explained.  In the beginning, it turns on, so to speak, then it takes over the residual emissions and then it generates the negative emissions. These technologies would have to be ramped up over time. Economically, there are three main ways of dealing with climate change. Dealing with the damage caused by climate change - adaptation. The question of how this damage can be reduced. This is avoidance.  Then there is the question of how this avoidance can be supplemented by these removals from the atmosphere in order to achieve net zero.

In economic terms, these are all trade-offs. Löschel: “It is always clear that there is an optimum between these three compartments of avoidance, adaptation and extraction. In economic terms, it usually doesn‘t make sense to go too far in one of these directions, but we need a good optimum. It also makes no sense, for example, to reduce emissions to zero, because then the last emission market avoidances become infinitely large and infinitely expensive.” Instead, we will have to find an optimum where things are brought into harmony so that the damage and costs are balanced out across these three options.

In his view, this is a very important boundary condition. According to Löschel, we also need to increase these withdrawals because they help us to never have to reduce emissions too much and thus cushion the excessive costs that arise in order to get rid of the last few percent.  This is discussed in the text. There also needs to be close coordination, particularly in terms of infrastructure. “That has already been mentioned here,” said Löschel. And we need to look at how the various applications such as BECCS (Bioenergy with Carbon Capture and Storage), DACCS (Direct Air Capture and Storage of Carbon Dioxide) and so on can be incorporated. This has not yet been done consistently in the reports, but would be a great necessity in his view.

In 2014, the IPCC also identified the costs that would arise if certain technologies were not available. In Germany, we are relatively big on excluding technologies. You can do that, but what does that mean? Excluding technologies, especially bioenergy with CCS, would be massively expensive. That means putting benefits and costs side by side. CCS involves risks, but the risks of a CCS ban would be much greater. In other words, an overall assessment is needed here.

There would probably need to be pragmatic consideration of how CO₂ storage could be tackled. Exporting environmental problems, i.e. shipping CO₂ to Norway, is a consideration that is also difficult. It raises ethical questions. This means that we would probably also have to consider how these geological storage options could also be developed onshore in the future. According to Professor Löschel, the advantages and disadvantages would at least have to be put on the table, “because we would probably like to have this option in the future” and we would also like to pursue it scientifically, said Löschel.

In this context, the colleagues came to the conclusion that CCU has limited potential. In any case, CCU is not a perfect replacement for CCS. The document poses further questions, which can also be read again, which is rather limiting in the context of CCU.  But it is one of the building blocks that are important, also for the way forward.

What is even more exciting from his point of view is how the ramp-up can be done and what that actually means. Once in the definition. “I think we should always say that this is not a full replacement for reduction.” Otherwise, acceptance of the instrument would quickly be lost. It is a supplement, as I have described it, and it is to be placed in a mix between adaptation, reduction and withdrawals and to be balanced economically, says Löschel. This must always be communicated accordingly, otherwise people will be lost. We also need to look at the different time scales and how this can be defined. “So I’d say difficult to avoid is unclear,” said Löschel. Is it technical, economic, infrastructural, static or dynamic? A certain amount of consensus needs to be reached as to what is actually meant, whether the term is broader or shorter. It will initially be kept relatively vague. But that will of course play a very big role in the implementation.

The question will then be how this upscaling is feasible. There are various chicken-and-egg problems. One that is heavily dependent on the infrastructure, i.e. the question of how a CO₂ infrastructure can be created that enables this option to be used at all. The second question is how economic framework conditions can be created so that the whole thing becomes attractive and also a business case. These are also the discussions that are currently being held. Decisions also need to be made here, both at EU level and nationally, as to what should be implemented in the future. According to Löschel, the objective must be to have a CO₂ price in the medium term that actually generates a revenue stream that makes it easier to ramp up economically. And that would work in different contexts. You could consider integrating this into the market step by step. This quantity that I add, via the negative emissions with removal, then ultimately limits the price in emissions trading. In other words, we need to consider how this should be controlled, what prices there should be in emissions trading and how much influence should be exerted. This is also a discussion that is currently being held. Climate target: climate neutrality 2045/ 2050 is actually a discussion about how many negative emissions should be introduced into the systems.

Ottmar Edenhofer, Director and Chief Economist of the Potsdam Institute for Climate Impact Research and Director of the Mercator Research Institute on Global Commons and Climate Change and Professor for the Economics and Politics of Climate Change at TU Berlin, has suggested setting up something like a carbon bank, i.e. a central bank that says these are acceptable CO₂ prices. That would then be an injection from this second pot of negative emissions, which could be made by an independent institution. Before that, a separate pot could be set up, where these negative emissions certificates would first be collected and then perhaps valued differently in some form, because separate targets would be set and then fed into the other market via such a line. “So I think that‘s where regulation really comes in,” said Löschel: “How can you set good incentives, knowing that prices and costs are still high at the moment? That is the one pot, the withdrawals, but then the hinge, how do I want to bring them into this market in order to keep prices low and then create this trade-off. Perhaps one possibility is to keep these things separate and then use an independent institution to clarify these difficult questions in the medium term, which obviously exist, because there are trade-off distribution issues to be resolved between the players in the various emissions trading systems. Perhaps it would be a good idea to create a European Central Climate Bank that can do this.”

Professor Wehrspohn asked whether there was a desire to merge two existing CO₂ markets, one that also promotes voluntary projects worldwide and the other that is mandatory. He asked Professor Löschel to classify this, the European ETS market and the international market. “What are the ideas on regional restrictions?” asked Wehrspohn.

Löschel confirmed that the voluntary market is the main driver because there is not yet any political involvement. We could talk about what it means to anchor this strongly in the regulatory context in terms of monitoring, reporting, verification obligations, etc., he said. This would then certainly have a different background when it comes to the regulatory context. How do regulations such as the Claims Directive, for example, or supply chain legislation and offsetting come in through the back door? According to Löschel, a lot of what comes from regulation will spill over. The two things would not remain completely separate, but there would be back doors in the implementation at European level, which would then have a global impact. This had become apparent in Baku. There is a fundamental framework for Article 6, these are the possibilities for interaction. “My feeling is that it all has to develop now,” said Löschel. European regulation will probably have a global impact in some form or another, because we want to make it usable in some way and then these other regulatory approaches will play a role. He hopes it will be less restrictive than RED III (“Renewable Energy Directive/RED III”), referring once again to Professor Locher’s presentation.

Certified CO₂ compensation of at least 1000 years with carbonation

Dr. Maria Gaudig from ITEL (German Lithium Institute) presented a method for binding CO₂ in order to actually generate negative emissions. The method binds CO₂ firmly to mineral residues. Gaudig presented the three strategies for dealing with unavoidable CO₂ emissions as a background to three key technical terms: CCS (Carbon Capture and Storage), CCU (Carbon Capture and Utilization) and CDR (Carbon Dioxide Removal).

There are two sources of carbon: On the one hand, industrial processes and power plants that release fossil carbon and, on the other, carbon in the atmosphere. Carbon is permanently stored in carbon sinks, for example in biological, geological and terrestrial processes or in building materials.

The term CCS refers to methods that start with fossil carbon and store it in carbon sinks. CCU methods also target fossil carbon, but store it in valuable products. However, these carbon products are not carbon sinks, but release the carbon back into the atmosphere.

Only CDR generates negative emissions by permanently storing carbon from the atmosphere in carbon sinks. Removing carbon from the atmosphere is crucial to achieving climate targets.

Carbon Dioxide Removal are negative emission methods

CDR methods “capture CO₂”, says Gaudig. Options range from nature-based methods such as reforestation and peatland restoration to hybrid methods that incorporate biomass into buildings and technology-based methods. The latter category includes methods of capturing CO₂ either directly from the air (DACCS) or via bioenergy (BEECS) and storing it permanently, which have recently been the subject of much research. These technology-based methods are currently on the rise. This also includes the method presented by Gaudig for the permanent chemical binding of CO₂ in products such as building materials.

Accelerated CO₂ binding to mineral residues

The basis for the developed method is carbonation, a chemical reaction in which CO₂ forms stable carbonates with active mineral substances. With carbonation, around a tenth of a tonne of CO₂ can be stored in one t of cement. In practice, carbonation takes place in the natural ambient air. Every concrete wall carbonates at this moment. The catch is that it takes up to 1000 years for significant amounts of CO₂ to be stored.

Carbonation basically works like this: CO₂ is chemically bound in mineral active minerals such as fayalite, an iron silicate, so that it can no longer dissolve and escape. Olivine, serpentine and wollastonite, along with other minerals, are suitable for this process and are found in the earth’s crust. As a result of mining, they can be found in products such as cement, concrete and ash, as well as in slag due to the ores that are used in metal processing.

Accelerated carbonation is possible. Chemistry knows some parameters for accelerating reactions. Optimal humidity increases the mobility of the ions and dissolves CO₂ into bicarbonates, the CO₂ concentration increases the probability of reactions, optimal pressure increases the solubility of CO₂ in water and optimal temperature in turn ensures a balance between CO₂ solubility and reaction speed. For high efficiency, the material must be in the smallest possible grains or as porous as possible, as the reaction takes place on the surface.

Carbonation potential of residual materials

Gaudig showed a photo of such a mineralization chamber, in which minerals are carbonated at an accelerated rate under optimized conditions at the ITEL together with the Martin Luther University Halle-Wittenberg. Her colleague Andreas Neumann was able to determine the carbonation potential of various residual materials, such as wollastonites. Under optimal temperatures, maximum saturation with CO₂ can be achieved in less than a day. “So what normally takes hundreds of years in the ambient air, we can accelerate here within a day,” said Gaudig.

The ITEL is actually working on lithium, why is research being conducted into carbonation? The extraction of lithium from ores produces tons of by-products. It is important that residual materials are not simply dumped. Research is being carried out into whether the by-products can also be used as gypsum or cement-like material. ITEL is working together with building material manufacturers who also have “huge stockpiles” of mineral-active residues. There is therefore plenty of material available for carbonation.

Residual materials as carbon sinks in commercial use

There are now already examples of the commercial use of residual materials as CO₂ sinks with accelerated carbonation. In the USA, GreenOre CleanTech is planning a plant in which 25000 t/a of CO₂ will be bound to the residual product iron slag. The good thing about carbonation is that the chemical properties of the product do not change significantly. Carbonated slag can be used as a road surface in the same way as conventional slag.

The company Neustark is another example of the commercial use of carbonation in German-speaking countries. Neustark brings construction material recyclers together with operators of biogas plants. In a mineralization plant, CO₂ is bound to the remains of buildings using the same principle. What is “particularly great” is that they achieve a storage efficiency of 85 to 93%. The high storage efficiency also includes the CO₂ generated during transport and the carbonation process, the grey energy. “That is remarkably high,” said Gaudig.

Potential of accelerated carbonation by 2030

Accelerated carbonation is already quite mature as a technology and is already being used commercially. Currently, the storage possibilities are still “hardly worth mentioning”. However, institutions assume that several million t of CO₂ will be stored annually by 2030 using this method.

In voluntary CO₂ compensation, the price for a certificate for one tonne of stored CO₂ is € 300 to 400. Biological methods of CO₂ storage fetch a few €/t. The difference, which justifies the high price for large tech companies and insurers, for example, lies in the long storage period. CO₂ compensation with carbonation certifies storage for at least 1000 years. Reforestation projects can usually guarantee 20 to 35 years of CO₂ storage. The fact that the EU already recognizes the method in its CRFC Regulation also speaks in favour of the method. Among other things, this sets out quality guidelines for valuable CO₂ sinks.

The high costs are currently still a challenge and the value chains still need to be established, for example by locating biogas plants as close as possible to the residual material recyclers. Even the substances processed with CO₂ cannot simply be reused, even if there is nothing technically preventing this until regulatory action is taken. Current studies assume that a market share of between ten and 30 percent can be expected for voluntary CO₂ certificates from 2035 and that this will continue to rise sharply. It will start soon, says Gaudig.

Using an illustration from ITEL’s science communication, Gaudig concluded with a hopeful message: carbonation could turn the spectre of CO₂ into a harmless form for humans and the climate.

Bigenic CO₂ from the chimney

“But now there really are companies that obtain biogenic CO₂ from the chimney and I am very pleased that we have such a guest here,” moderator Professor Wehrspohn led on to Dr Sebastian Kunz from Südzucker AG.

Dr Kunz was already on the podium at the CarbonCycleCultureClub in March 2022, where he spoke on the topic of sugar as a building material. The C4 on this topic took place in Zeitz. This time, Dr Kunz began by explaining what Südzucker is all about. The company employs a good 19000 people worldwide, has an annual turnover of € 10.3 billion and 100 production sites worldwide. But at its core, it is a European company. Its core competence is the processing of agricultural raw materials with the corresponding logistics. The company is divided into five segments: the classic sugar division, the specialties division bundles everything to do with nutrition and health under Beneo, and convenience food is also represented in the group via Freiberger. Portion Pack offers miniature packaging familiar from the catering and hotel sectors. The third segment, which is important for the contribution in C4, is CropEnergies. Until recently, it was listed on the stock exchange and Südzucker owned 70% of it. Last year, however, it was decided to fully reintegrate it and the company is in the process of buying the last remaining shares. The ethanol business is bundled in CropEnergies. Südzucker has three ethanol plants in which ethanol is produced from feed grain and residues from food production and, as a combined product, biogenic CO₂, among other things.

The two topics are important for outsiders: Proteins and bio-based chemicals. These are the fields in which products will be further developed in the future: on the one hand in the area of non-animal proteins, and on the other hand bio-based chemicals: “We have biogenic carbon and we want to use it not only in today’s applications, which are food, feed and energy, but also in material use,” said Dr Kunz. Südzucker is part of the energy-intensive industry.

Sugar is the easiest example of this. How is sugar produced? It‘s actually quite simple, according to Kunz. You get the beet. You have to wash it, you have to cut it. Once the beetroot has been cut into so-called beet pulp, the whole thing is soaked and a sugar juice, the so-called thin juice, is extracted from the beet pulp. This has a sugar content of 15 to 18%. The rest is mostly water. Purification stages then take place. To remove the water from the thin juice, it is thickened to produce what is known as thick juice. The sugar content is already over 70%. It is then crystallized. This means that large amounts of water have to be removed from the product. “And anyone familiar with water evaporation knows that this is an energy-intensive process,” explained Kunz.

“We’ve also talked about coal today,” he added.  The sugar industry is a very old industry. Historically, many factories were built where there was beet and coal as energy. In the energy sector, CO₂ naturally also plays a negative role for the company. For Südzucker, it is important to make production CO₂-neutral in the future. On the one hand, there are conventional measures to increase efficiency: Thermal insulation, better heat integration. These are measures that have always taken place in the past. But how can we make further progress? Of course, electrification is also a key issue. The main aim here is to integrate heat pumps in order to make better use of waste heat and thus reduce primary energy requirements.

A heat pump is a waste heat user, but not a heat generator. According to Kunz, this is often misunderstood in politics. You cannot achieve 100% electrification with a heat pump and providing the remaining energy, the primary energy, with electricity is also not trivial and does not make sense, he explained. That is why the company’s approach is to electrify with heat pumps in order to further reduce the energy requirement and provide the basic energy with so-called green gases. Green gases include the possibility of using green hydrogen. Another possibility for the company is to go into biogas production and then use this biogas for its own production, as there are always residues from production. The concept was submitted in the application for the climate protection contract. Südzucker was awarded the prize for the Zeitz plant with its CO₂-neutral sugar production project proposal and will now go into implementation. Exactly with the measures he had described, said Kunz.

Südzucker also has biogenic CO₂. In the sugar factory at the production site in Zeitz, beet is processed into white sugar and the beet pulp will be turned into biogas in future. Wheat starch is produced in the starch factory and glucose syrups are then made from the wheat starch. The by-products are wheat proteins and husks, which are used in animal feed. In ethanol production, feed grain is processed as well as residues from the other two production facilities, i.e. residues containing carbohydrates.

Ethanol production is very easy to explain. Anyone who knows how whisky is made also knows how ethanol is produced on a large scale. “We ferment just like a whisky distiller,” Kunz reported. After fermentation, the alcohol has to be distilled out. Today, most of the alcohol goes into the fuel market. But larger quantities are also used in the food sector. What remains of the fermentation residue is dried. The fermentation broth mainly contains proteins, which can be further processed as protein-rich animal feed. As with any fermentation, carbon dioxide is produced. “We are already using some of this CO₂ today, liquefying it and feeding it into the beverage industry. However, we also still have unused reserves,” said Kunz. It can be said that, in principle, one tonne of biogenic CO₂ is produced from fermentation for every tonne of ethanol. In Zeitz, Südzucker has a production capacity of just over 300000 t. This means that the potential of biogenic CO₂ is also over 300000 t. “With biogas production, we still have new potential sources of CO₂,” says Kunz. CO₂ in the five-digit tonnage range is produced here.

According to Kunz, biogenic CO₂ will certainly have a value in the future. The question for the company is how more value can be created with this CO₂. One topic that has already been addressed today is methanol, according to Kunz. “We have already looked at the topic of methanol in the funding project,” said Kunz. With the entire value chain: from wind turbines to electrolysis, the production of methanol from biogenic CO₂ and green hydrogen, and have also looked at the application. We are also convinced that this is a very sensible and sustainable value chain, but we can also see - we have already talked about RED II and III (Renewable Energies Directive II and III) today - how narrow the framework is for what green hydrogen is. “Under such conditions, such projects are of course not viable,” Kunz summarized.

However, if the framework conditions change, then it must be clearly stated that biogenic CO₂ in combination with hydrogen and green methanol is a product that can be used in many different ways. Methanol can be used in the conventional infrastructure of refineries and thus contribute directly to greenhouse gas reduction. It can be used in the shipping sector - Maersk, for example, has ordered numerous methanol-capable ships - and last but not least, of course, in the aviation sector: Sustainable Aviation Fuels (SAF). At the moment, the main focus here is on used cooking oils (UCOs), but even these will be used up at some point and then synthetic fuels will probably also be needed in this area.

Professor Ralf Wehrspohn summarized: “We are at the beginning of penetrating this topic. I have a really interesting panel here today. We are getting closer.” It remains to be seen how the international carbon market will come together with the European market and how stable this voluntary CO₂ market will be. There are still many unanswered questions. “This won‘t be our last C4 Club on this issue,” says Professor Wehrspohn.

For him, the key to these questions is ultimately: “Do I have to make everything atom-specific?” Does the molecule that comes from the cement plant, for example, really have to be pressed or carbonated into this specific molecule, or can such a molecule be taken anywhere in the world? “If we discuss the topic again, then that could be a key,” he said, giving a preview. Then there would no longer be a need for transportation and less energy would be required - that could be a solution. Of course, this has many implications “that we haven’t even thought through yet, which we have discussed today. At this point, I think we end up with questions. Which is good, because the idea of the CarbonCycleCultureClub is also to ask questions and not answer them all,” said Professor Wehrspohn.

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