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Summary Carbon dioxide (CO2) foam has been widely studied in connection with its application in enhanced oil recovery (EOR). This paper reports an experimental study concerning CO2 foam propagation in a surfactant-saturated Bentheim sandstone core and the subsequent liquid injection with the aid of X-ray computed tomography (CT). The experiments were carried out under various system backpressures. It is found that CO2 foam flows in a characteristic front-like manner in the transient stage and that the water saturation keeps at relatively high level at the outlet of the porous media because of CO2 solubility and capillary end effect. The subsequent surfactant solution injection shows a significant fingering behavior, accompanied by a low flow resistance over the core. It is also found that CO2 foam flow shows higher liquid saturation near the outlet and lower pressure drops under higher system backpressures. This can be attributed to the solubility of CO2 in the liquid phase. The results indicate the advantage of using foam in EOR processes such as water alternating foam (WAF), in which foam flow has higher sweep efficiency and stronger mobility control ability compared, for instance, to water alternating gas (WAG). Nevertheless, care should be taken during the water-injection stage in order not to favor the fingering.

<p>Commonly used host rock reservoirs for Enhanced Geothermal Systems (EGS) are composed of granite, as they display highly conductive and sustainable fracture networks after stimulation. However, considering the large amount of metamorphic rocks in Europe’s underground, these rock types may also show a large potential to extract geothermal energy from the subsurface. Within the framework of the European Union’s Horizon 2020 initiative ‘MEET (Multi-Sites EGS Demonstration)’, we are conducting fracture permeability experiments at elevated confining pressures, p<sub>c</sub>, temperatures, T, and differential stresses, </p>

To overcome the problem of insufficient conformational sampling within biomolecular simulations, we have developed a novel Hamiltonian replica exchange molecular dynamics (H-REMD) scheme that uses soft-core interactions between those parts of the system that contribute most to high energy barriers. The advantage of this approach over other H-REMD schemes is the possibility to use a relatively small number of replicas with locally larger differences between the individual Hamiltonians. Because soft-core potentials are almost the same as regular ones at longer distances, most of the interactions between atoms of perturbed parts will only be slightly changed. Rather, the strong repulsion between atoms that are close in space, which in many cases results in high energy barriers, is weakened within higher replicas of our proposed scheme. In addition to the soft-core interactions, we proposed to include multiple replicas using the same Hamiltonian/level of softness. We have tested the new protocol on the GTP and 8-Br-GTP molecules, which are known to have high energy barriers between the anti and syn conformation of the base with respect to the sugar moiety. During two 25ns MD simulations of both systems the transition from the more stable to the less stable (but still experimentally observed) conformation is not seen at all. Also temperature REMD over 50 replicas for 1ns did not show any transition at room temperature. On the other hand, more than 20 of such transitions are observed in H-REMD using six replicas (at three different Hamiltonians) during 6.8ns per replica for GTP and 12 replicas (at six different Hamiltonians) during 8.7ns per replica for 8-Br-GTP. The large increase in sampling efficiency was obtained from an optimized H-REMD scheme involving soft-core potentials, with multiple simulations using the same level of softness. The optimization of the scheme was performed by fast mimicking [J. Hritz and C. Oostenbrink, J. Chem. Phys. 127, 204104 (2007)].

Der Klimawandel ist eine globale Herausforderung, wobei die geschätzten Kosten für seine Eindämmung zwischen 1,6 und 3,8 Billionen USD pro Jahr liegen. Als Pionier im Bereich des Klimaschutzes verfügt die Europäische Union über das weltweit umfangreichste Emissionshandelssystem (87 % des globalen Wertes von 865 Mrd. USD im Jahr 2022). Die kumulative Dissertation ist in drei Artikel unterteilt und beschäftigt sich mit der Rolle von forstwirtschaftlichen Kohlenstoffgutschriften sowohl auf den Verpflichtungsmärkten als auch auf den freiwilligen Kohlenstoffmärkten. Dabei werden Potenziale für forstwirtschaftliche Investitionen in diesen beiden Märkten untersucht. Im ersten Artikel wird ein Überblick über die Klimastrategie der Europäischen Union gegeben, wobei der Schwerpunkt auf der Entwicklung des EU-Emissionshandelssystems (EU ETS) und der Rolle von Waldkohlenstoffzertifikaten für Kompensationszwecke sowohl in der Europäischen Union als auch international liegt. Wir argumentieren, dass die Europäische Union weiterhin ein beträchtliches Potenzial der Wälder - insbesondere der tropischen Wälder - als natürliche Kohlenstoffsenken ungenutzt lässt. Im Gegensatz dazu zeigen wir auf, dass die Regulierungsbehörden aus den Erfahrungen und Verbesserungen der Vergangenheit, den Sustainable Carbon Cylces der Europäischen Union und der Fertigstellung und Entwicklung des Regelwerks für Artikel 6 des Pariser Abkommens lernen können. Wir unterbreiten einen Vorschlag zur Änderung der EU-ETS-Verordnung, indem wir die kürzlich im Trilog vereinbarte Gesetzgebung der Europäischen Kommission zur Erhöhung des linearen Reduktionsfaktors von 2,2 % auf 4,2 % auf die Anrechenbarkeit von Waldkohlenstoffgutschriften übertragen, was zu einem zusätzlichen Finanzierungspotenzial für Forstprojekte zur Erhöhung der notwendigen Kohlenstoffsenken führt. Gleichzeitig wird durch die Möglichkeit, in begrenztem Umfang in Neutralisierungsprojekte zu investieren, das Risiko gemindert, dass regulierte Unternehmen bei der Erreichung der Emissionsreduktionsziele überfordert werden. Das Überdenken des Status quo erfordert nicht nur eine Stärkung der Robustheit von Kohlenstoffprojekten, sondern kann auch den Widerstand von politischen Entscheidungsträgern und NGOs überwinden. Emissionsgutschriften aus Wäldern sind in den meisten Emissionshandelssystemen von Bedeutung, da sie ein kosteneffizientes Mittel zum Ausgleich von schwer zu kompensierenden Emissionen darstellen. Bislang war dies im Emissionshandelssystem der Europäischen Union (EU ETS) nicht der Fall. Da das Regelwerk des Pariser Abkommens nun fertiggestellt ist, könnte sich jedoch die Gelegenheit bieten, diesen Flexibilitätsmechanismus in der europäischen Klimapolitik wiederzubeleben. Auf der Grundlage von 24 Experteninterviews untersuchten wir im zweiten Artikel das forstwirtschaftliche Potenzial innerhalb des EU-Emissionshandelssystems über kurz-, mittel- und langfristige Zeiträume. Wir kamen zu dem Ergebnis, dass das Erfüllungssystem bis 2030 blockiert bleiben wird, dass aber langfristig ein Übergang zur Einbeziehung von forstbasierten Entnahmen und Reduktionen wahrscheinlicher ist. Obwohl forstwirtschaftliche Projekte in der EU auf große Zurückhaltung stoßen, herrscht Einigkeit darüber, wie wichtig sowohl technologische Lösungen als auch solche Initiativen für den Klimaschutz sind. Um das Potenzial der Forstwirtschaft in Zukunft voll auszuschöpfen, müssen andere Methoden und Instrumente (z. B. Haftungsregelungen), strengere Rechtsvorschriften für sozioökonomische Faktoren (z. B. Landnutzungsrechte), die Überwindung von Umsetzungshürden (z. B. keine Kompromisse bei der Abschreckung durch Abschwächung) und eine offene politische Haltung eingeführt werden. Diese Studie bietet eine umfassende Perspektive auf die Hindernisse und Potenziale von Forstprojekten im Rahmen des Compliance-Systems der EU, die bei der Wiederaufnahme der Diskussion über die künftige Förderfähigkeit unbedingt berücksichtigt werden muss. Die Ergebnisse der Studie legen nahe, die Hindernisse für die Bereitstellung von Emissionsgutschriften in der nächsten Phase des EU-Emissionshandelssystems ab 2030 unverzüglich zu beseitigen. Der freiwillige Kohlenstoffmarkt (Voluntary Carbon Market, VCM) hat in den letzten Jahren ein beispielloses Wachstum erlebt, das durch die Verpflichtungen der Unternehmen begünstigt wurde. Die künftige Entwicklung hängt jedoch von der Strategie des Pariser Abkommens ab, insbesondere von Artikel 6. Daher werden im dritten Artikel die verschiedenen vorgeschlagenen Mechanismen und ihre Auswirkungen auf den VCM analysiert. Von besonderer Bedeutung ist der Bedarf an entsprechenden Anpassungen (CA) und wie sich diese Anforderung auf den VCM auswirkt. Der "neue" Typ von Kohlenstoffgutschriften, der auf der CoP27 eingeführt wurde, nämlich die "Mitigation Contribution A6.4ERs", wird die Konsolidierung des VCM wahrscheinlich beschleunigen. Auf der Grundlage einer halbsystematischen Überprüfung und von Experteninterviews (N = 20) sprechen die derzeitigen kurzfristigen Aussichten (~2030) für ein weiteres Wachstum des VCM, trotz bestehender Unsicherheiten aufgrund der unvollständigen technischen Details des Rahmens. Darüber hinaus halten die meisten Experten den Artikel 6-Rahmen nach intensiven und gründlichen Verhandlungen für erfolgreich. Mittelfristig (~2030-2045) wird es wahrscheinlich zu einem Marktübergang kommen. Dementsprechend wird der VCM seine Nische finden und das gegenwärtig verwendete Ausgleichsinstrument neu bewerten müssen. Diese Neubewertung muss über eine reine Kohlenstoffperspektive hinausgehen und sich auf die Zusatznutzen konzentrieren, um die Legitimität des VCM zu erhalten. Langfristig (~2045) deuten die Ergebnisse auf einen Rückgang des VCM hin, da er möglicherweise mit Compliance-Märkten kombiniert wird. Die Infrastruktur und die Robustheit der Artikel-6-Regelwerke werden jedoch dazu beitragen, das volle Wachstumspotenzial des VCM zu gewährleisten. Climate change is a global challenge, with estimated mitigation costs ranging from USD1.6 to USD3.8 trillion per year. As a pioneer in climate action, the European Union has the most extensive emissions trading system worldwide (87% of the global value of USD865 billion in 2022). The cumulative PhD thesis is divided into three articles dealing with the role of forest carbon credits in both compliance and voluntary carbon markets as well as investigating further potentials for forest investments in both of these markets. In the first article, we review the European Union's climate strategy, emphasizing the EU Emissions Trading System (EU ETS) development, and the role of forest carbon credits for offsetting purposes, both in the European Union but also internationally. We argue that the European Union continues to leave a significant potential of forests - in particular tropical forests - as natural carbon sinks unattended. In contrast, we reveal that the regulators can learn from the experiences and improvements made in the past, the European Union’s Sustainable Carbon Cylces and the finalization and development of the rulebook for Article 6 of the Paris Agreement. We present a proposal on changes to the EU ETS regulation by converting the European Commission's legislation, recently agreed in the trilogue, to increase the linear reduction factor from 2.2% to 4.2% to the eligibility of forest carbon credits, resulting in additional funding potential for forestry projects to increase necessary carbon sinks. Simultaneously, allowing flexibility of investing to a limited extent in neutralization projects mitigates the risk of overstressing regulated companies to reach the emission reduction targets. The re-thinking of the status quo will not only require strengthening the robustness of carbon projects, but may also overcome the resistance of policy makers and NGOs. Forest-based carbon credits are crucial in most Emissions Trading Schemes as they offer a cost-efficient means of offsetting hard-to-abate emissions. To date, this has not been the case in the European Union Emissions Trading Scheme (EU ETS). However with the Paris Agreement rulebook now finalized, there could be an opportunity to revive this flexibility mechanism in European climate policy. Based on 24 expert interviews, we examined in the second article the forest potential within the EU ETS across short, medium, and long-term time frames. We found that the compliance system will remain blocked until 2030, but there is a greater likelihood of transitioning towards the inclusion of forest-based removals and reductions in the long term. Although forestry projects have faced significant reluctance in the EU, there is unanimous agreement on the importance of both technological solutions and such initiatives for climate protection. To fully leverage the potential of forest activity in the future, it will be necessary to adopt different methods and tools (e.g., liability regimes), stricter legislation on socio-economic factors (e.g., land use rights), overcoming implementation hurdles (e.g., do not compromise deterrence through mitigation), and maintaining an open political stance. This study provides a comprehensive perspective on the barriers and potentials of forestry projects within the compliance system of the EU which is essential to be addressed when re-opening the discussion on future eligibility. The implication of the findings suggest an immediate start to adopt to the barriers for carbon credit readiness in the next phase of the EU ETS beginning of 2030. The voluntary carbon market (VCM) has seen unprecedented growth over the past years, facilitated by corporate commitments. However, future development depends on the Paris Agreement strategy, in particular, Article 6. Therefore, the third article analyzes the various mechanisms suggested and their implications on the VCM. Of particular importance is the need for corresponding adjustments (CA) and how this requirement spills over to the VCM. The “new” type of carbon credits introduced during CoP27, that is, the “mitigation contribution A6.4ERs” will likely accelerate the consolidation of the VCM. Based on a semi-systematic review and expert interviews (N = 20), the current short-term (~2030) prospects support further growth of the VCM despite existing uncertainties caused by the incomplete technical details of the framework. Moreover, after intense and thorough negotiation, most experts deemed the Article 6 framework successful. In the mid-term (~2030-2045), a market transition will likely occur. Accordingly, the VCM will need to find its niche and reassess the current compensation tool used. This reassessment must go beyond a mere carbon perspective and focus on co-benefits to prolong the legitimacy of the VCM. Long-term (~2045) results indicate a decline in the VCM as it potentially combines with compliance markets. However, the infrastructure and robustness of Article 6 rulesets will help to ensure the full growth potential of the VCM.

This report describes the modelling approach, input data, scenarios of biobased fertiliser application, and the results and conclusions in terms of environmental impacts. For all demonstration plants scenarios were worked out in terms of application rates of digestate and/or biobased fertilisers, and the associated applied nutrients and heavy metals to the soil. Thereafter, the model simulations were carried out which were discussed during a SYSTEMIC internal webinar. Finally, the outcome of the environmental impact assessments were reviewed by the demoplants and other partners of the SYSTEMIC project consortium.

Smart Grid holds the promise of engaging end users in the energy market and operations - both in terms of reacting to energy prices intelligently and in terms of providing ancillary services to the markets. Demand response becomes “Dispatchable Demand Response” (DDR) and AMI enabled real time pricing becomes “Dynamic Pricing” (DP) implying that end use appliances and other consumptions can see day ahead, hour ahead, and intra hour prices and react to them.

The levels of production diseases (PD) and the cow replacement rate are high in dairy farming. They indicate excessive production demands on the cow and a poor state of animal welfare. This is the subject of increasing public debate. The purpose of this study was to assess the effect of production diseases on the economic sustainability of dairy farms. The contributions of individual culled cows to the farm’s economic performance were calculated, based on milk recording and accounting data from 32 farms in Germany. Cows were identified as ‘profit cows’ when they reached their individual ‘break-even point’. Data from milk recordings (yield and indicators for PD) were used to cluster farms by means of a principal component and a cluster analysis. The analysis revealed five clusters of farms. The average proportion of profit cows was 57.5%, 55.6%, 44.1%, 29.4% and 19.5%. Clusters characterized by a high proportion of cows with metabolic problems and high culling and mortality rates had lower proportions of profit cows, somewhat irrespective of the average milk-yield per cow. Changing the perception of PD from considering it as collateral damage to a threat to the farms’ economic viability might foster change processes to reduce production diseases.

Photoexcitation and charge carrier thermalization inside semiconductor photocatalysts are two important steps in solar fuel production. Here, photoexcitation and charge carrier thermalization in a silicon wafer are for the first time probed by a novel, yet simple and user-friendly Attenuated Total Reflectance Infrared spectroscopy (ATR-IR) system.