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E-fuels are a promising technological option to reduce the carbon footprint in the transportation sector. To ensure the renewable origin of electricity-based fuels and minimize the impact of power-to-liquid facilities on the electricity grid, the European Union implemented electricity purchase conditions within the Renewable Energy Directive II. In this work, we analyze the impact of these electricity purchase conditions on the optimal placement, dimensioning and operation of facilities and the German electricity system. The results show that implementing the proposed electricity purchase conditions increases electrolysis capacity by 15.8% and reduces utilization by 672 h in 2030. With the constrained electricity supply, the power-to-liquid facilities concentrate on network nodes with high renewable potential, while the carbon dioxide supply loses importance. Overall, the German electricity system is not heavily affected by the proposed purchase conditions as the required renewable generation capacities only increase slightly. At the same time, carbon dioxide abatement costs rise by 14.3% by introducing the electricity purchase conditions.

Tackling the grand challenges of global climate change for the sustainability of ecological and societal systems requires data and expertise from Russia, the world's largest country that has the longest Arctic shoreline and the largest forest biome, peatland and permafrost zones. Academic relations and scientific collaborations with Russian scholars and institutions must continue despite the ensuing geopolitical crisis since 2022.

This study aimed to optimize the process parameters and evaluated economic feasibility for biodiesel production. A pyrolytic rice straw ash (RSA) support with various amounts of calcium oxide (25–35 wt%) and calcination temperatures (600–800 °C) were used in the study. The results identified 35 wt% of CaO/RSA and calcination at 600 °C as the most effective catalyst with turnover frequency (TOF) of 2.88 h$^{−1}$ for biodiesel synthesis, giving a biodiesel yield of 96.49%. The optimal conditions for biodiesel production included a methanol: palm oil molar ratio of 9.34:1, a catalyst loading of 4.87 wt%, 175 min reaction time, and 65 °C reaction temperature. The study also included a techno-economic analysis of biodiesel production, revealing a payback period of 7.17 years, an internal rate of return of 17.20%, and a net present value of 4,151,905.61 USD. These findings pave the way for more sustainable and economically feasible biodiesel production.

Industrial electricity consumers with flexible demand can profit by adjusting their load to short-term prices and by providing balancing services to the grid. Markets which support this kind of short-term position adjustment are the day-ahead market and balancing markets. We propose a formulation for a combined optimization model that computes an optimal distribution of flexibility between the balancing and day-ahead markets. The optimal solution also includes the specific bids for the day-ahead and balancing markets. Besides the expected profits of each market and their individual bidding languages, our model also takes their different roles in a continuous marketing of flexibility into account. To prevent overrating short-term profits we introduce a variable penalty term that adds a cost to unfavorable load schedules. We evaluate the optimization model in a rolling horizon case study based on the setting of a virtual battery at TRIMET SE, which is derived from a flexible aluminum electrolysis process. For such a battery we compute a daily optimal split of flexibility and trading decisions based on data in the period 04/2021 - 03/2022. We show that the optimal split is more profitable than using only one market or a fixed split between the markets. Comment: 29 pages, 13 figures, 1 table

Neutron embrittlement of reactor pressure vessel (RPV) steels limits the safe operational time of nuclear reactors. Microcracks in RPV steels are known to originate from cleaved precipitates, inclusions or grain boundaries, which eventually lead to brittle fracture. In most cases, these precipitates are reported as carbides. Latest research indicates the critical fracture event to be the crossing of grain boundary instead of the particle-matrix interface by the microcrack. Very few works have performed detailed fractography, which revealed the size and type of the feature found in the crack nucleation centre, together with metallographic bulk investigations. Additionally, the effect of neutron irradiation on microcrack nucleation is unknown. In the present work, detailed fractography and metallography is performed on a RPV steel in both its unirradiated as well as neutron irradiated state. While no particles were involved in more than 1/3 of all samples, a particle in the centre of the initiation site has been identified in a majority of the cases. Those particles are either Mo-rich carbides or Al-rich inclusions. In comparison, the metallographic analysis of the bulk steel reveals Mo-rich and Mn-rich carbides. Mn-rich carbides constitute the majority of all carbides in the steel but are never found to be responsible for brittle fracture initiation. Only a small fraction of observable carbides is Mo-rich which are responsible for fracture. Thus, the present work demonstrates a discrepancy between particles found in brittle fracture initiation sites and particles that are directly observable in bulk steel. Some of the initiating particles are extremely rare in the bulk. Furthermore, it is revealed that the local fracture stress does not depend on the type or size of particle or grain involved at the initiation site. In conclusion, the fracture stress strongly depends on the type of the grain boundary, rather than on a stress based upon a Griffith criterion, which considers particle or grain size alone. The brittle fracture mechanism was found to be unaffected by neutron irradiation. These findings could help refine modelling of the critical brittle fracture stress and fracture toughness using microstructural parameters as input.

Energy reports 9, 1977-1989 (2023). doi:10.1016/j.egyr.2023.01.016 Published by Elsevier, Amsterdam [u.a.]

There is a growing number of national, subnational and even company targets for net-zero emissions of CO2 in support of the Paris Climate Agreement goals of limiting the global average temperature increase within 1.5 °C by 2100. The challenges faced by developing countries in achieving net-zero emissions targets are, however, very prominent due to their common desire for rapid economic growth, improved socio-economic conditions, and greater climate resilience. In addition, this has to overcome many constraints related to the competitiveness, acceptability, and sustainability of proposed and planned low-carbon initiatives. It is thus very important to understand the economic and technical characteristics of net-zero emissions concepts and pathways. The constraints can best be addressed if actual and transparent co-benefits related to these initiatives are identified and reflected during their implementation. Here we employ the Low Emissions Analysis Platform (LEAP) to examine Nepal’s recently introduced ‘Long-term Strategy for Net-zero Emissions’ and to estimate anticipated co-benefits in terms of reducing air pollutants emission and enhancing energy security and energy equity. Under the reference scenario (REF), the annual CO2 emission is expected to increase from 23 MtCO2 in 2019 to 79 MtCO2 in 2050 with significant increase in air pollutants emissions in the range of 60% (Organic Carbon) to 183% (SO2), increase in energy import dependency, reaching electricity consumption per capita below one-quarter of the world average. Under the ‘With Additional Measures (WAM)’ strategy scenario, air pollutants would be reduced in the range of 70% (Organic Carbon) to 85% (Black Carbon) respectively, in 2050 as compared to the REF. Similarly, it results drastic improvement in energy security indicators and energy equity. It is expected that the findings of this study will provide useful input to policymakers, private sector, societal actors and researchers in support of successful implementation of the initiatives for sustainable socio-economic transformation pathways.