178 research outputs found

    Gibt es bessere Alternativen zu fossilen Kraftwerken fĂŒr die Versorgungssicherheit der Schweiz mit Strom? : eine Analyse und Interpretation von diversen Studien zur Stromversorgungssicherheit

    Get PDF
    Auf Anregung der ElektrizitĂ€tskommission (ElCom) aus dem Jahr 2021 hat der Bundesrat im Januar 2023 mit einer Verordnung entschieden, fossile Reserve-Kraftwerke mit einer maximalen Leistung von 1'000 MW zu beschaffen und entsprechende Ausschreibungen im FrĂŒhling 2023 durchzufĂŒhren (Bundesrat, 2023a). Diese sollen die Versorgungssicherheit mit Strom fĂŒr die Schweiz in den nĂ€chsten Jahren gewĂ€hrleisten. Im Herbst 2022 lancierte der Bundesrat zudem eine Energiesparkampagne, welche in den Wintern 22/23 und 23/24 auf freiwilliger Basis jeweils zu Winterstrom-Einsparungen von 10% bzw. 3.1 TWh fĂŒhren sollen (Bundesrat, 2022). In dieser Studie werden Berichte analysiert, welche zur Entscheidung des Bundesrates ĂŒber die Beschaffung von weiteren fossilen Kraftwerken gefĂŒhrt haben und Alternativen zu den fossilen Reserve-Kraftwerken aufgezeigt. Die grösste Bedrohung der Schweizer Stromversorgung stellt ein gleichzeitiger Ausfall aller Schweizer Atomkraftwerke im spĂ€ten Winter dar, wenn die Speicherseen leer sind. In einem solchen Szenario fehlt der Schweiz insgesamt 1.6 TWh Strom und die fehlende Kraftwerkleistung betrĂ€gt bis zu 6'000 MW (ElCom, 2021b). Bei einer Einbindung der Schweiz in den EU-Strombinnenmarkt könnte selbst dieser Fall und auch der Ausfall von weiteren Kraftwerken durch zusĂ€tzliche Stromimporte bewĂ€ltigt werden. Falls die EU ab 2025 die sogenannte 70%-Regel im Strommarkt auch bei einem Ausfall aller Schweizer Atomkraftwerke strikt auslegen wĂŒrde und/oder selbst einen Stromengpass hĂ€tte, kĂ€me es in der Schweiz dann voraussichtlich zu einer Strommangellage in der oben erwĂ€hnten Grössenordnung. Da die Schweiz mit ihrem Stromnetz physikalisch eng in das europĂ€ische Stromnetz eingebunden ist, hĂ€tte eine solche Situation mit hoher Wahrscheinlichkeit auch Konsequenzen auf die NachbarlĂ€nder. Insofern stellt die Annahme der strikten Auslegung der 70%-Regel eine sehr konservative Annahme dar. Eine Gasmangellage in Europa und als Folge davon eine reduzierte Stromproduktion aus europĂ€ischen Gaskraftwerken wĂŒrde im Extremfall zu einem Stromdefizit in der Schweiz von 0.405 TWh fĂŒhren. Kurzfristig stellt dies fĂŒr die Schweiz vermutlich die grössere Bedrohung als AusfĂ€lle von Kraftwerken dar. Die fehlende Strommenge entspricht etwa der Winterstromproduktion, welche im Jahr 2023 durch den Bau von neuen Photovoltaikanlagen dazu kommt oder 13% des Winterstrom-Einsparziels des Bundesrates. Als Lösung fĂŒr beide Bedrohungen wird von der ElCom im Konzept Spitzenlast-Gaskraftwerk eine Kombination aus mehreren Reserve-Gaskraftwerken mit insgesamt maximal 1'000 MW Leistung und einer Wasserkraftreserve in den Speicherseen vorgeschlagen. Die Gaskraftwerke kĂ€men bereits mehrere Wochen vor einer absehbaren Strommangellage zum Einsatz und wĂŒrden primĂ€r dazu dienen, die Speicherkraftwerke zu schonen, sodass diese einen höheren FĂŒllstand hĂ€tten und die benötigte Leistung erbringen könnten. Das Schonen der Speicherkraftwerke muss aber nicht zwingend durch fossile Kraftwerke erfolgen. Ein rascherer Ausbau der erneuerbaren Energien gemĂ€ss dem aktuell diskutierten Mantelerlass oder Energieeffizienzmassnahmen hĂ€tten trotz witterungsabhĂ€ngiger Einspeisung denselben Effekt (BFE, 2022b). Auch erhöhte Stromimporte oder das vom Bundesrat kurzfristig angestrebte Strom-Einsparziel hĂ€tte dieselbe Wirkung. Letztendlich geht es nur darum, mehr Strom im Winterhalbjahr zu erzeugen oder weniger Strom zu verbrauchen und damit die Speicherkraftwerke zu schonen. Der FĂŒllstand der Speicherseen im SpĂ€twinter wĂ€re dadurch hoch, damit könnten die Speicherkraftwerke allfĂ€llige AusfĂ€lle von anderen Kraftwerken oder fehlende Importe ĂŒberbrĂŒcken. Es muss jedoch durch entsprechende Massnahmen sichergestellt werden, dass das zusĂ€tzlich zur VerfĂŒgung stehende Stromproduktionspotential im Winter von den Besitzern der Speicherkraftwerke nicht frĂŒhzeitig am Markt verkauft wird. Das Schonen der Stauseen erhöht nur dann die Versorgungssicherheit, wenn die zusĂ€tzliche Stromproduktion auch wirklich zu grösseren Reserven in den Speicherseen fĂŒhrt. Da die grösste Bedrohung aus einem Ausfall der Atomkraftwerke besteht und die Reservegaskraftwerke bereits Wochen vor dem Ausfall eingeschaltet werden mĂŒssten, stellt sich grundsĂ€tzlich die Frage, inwiefern ein Ausfall der Atomkraftwerke ĂŒberhaupt Wochen im Voraus vorhersehbar ist. Bei einem ĂŒberraschenden Ausfall der AKW bei leeren Stauseen und stark eingeschrĂ€nktem Stromimport (Worst-Case-Szenario) kĂ€me es trotz fossilen Reservekraftwerken zu einer Strommangellage in der Schweiz. Ein rascherer Ausbau der erneuerbaren Stromproduktion im Winter und/oder Stromeinsparungen wĂŒrde die Speicherseen in jedem Falle schonen und könnte somit besser zur Versorgungssicherheit beitragen als fossile Kraftwerke, welche bei ĂŒberraschenden AusfĂ€llen von Grosskraftwerken vermutlich zu spĂ€t zum Einsatz kommen wĂŒrden. Entscheidend ist aber in allen FĂ€llen, dass die Bildung einer Wasserkraftreserve in den Stauseen gesetzlich vorgeschrieben und ĂŒberwacht wird, damit die zusĂ€tzliche Winterstromproduktion nicht einfach auf dem Markt verkauft werden kann. Zusammenfassend sind eine verbindliche Speicher-Wasserkraftreserve in Verbindung mit einem raschen Ausbau der erneuerbaren Stromproduktion (mindestens so rasch wie im Mantelerlass Energie vorgesehen) und Effizienzmassnahmen die beste Lösung fĂŒr eine sichere Stromversorgung der Schweiz. Die fossilen Reservekraftwerke werden dadurch obsolet. Insofern wĂ€re es absolut nicht nachvollziehbar, wenn die Schweiz noch weitere fossile Reservekraftwerke beschaffen wĂŒrde. Deren Kosten von schĂ€tzungsweise 1.4 Mia. Fr. wĂŒrde wesentlich zielfĂŒhrender in den Ausbau von Energieeffizienz und in die erneuerbare Stromproduktion investiert

    The terrestrial carbon budget of South and Southeast Asia

    Get PDF
    Accomplishing the objective of the current climate policies will require establishing carbon budget and flux estimates in each region and county of the globe by comparing and reconciling multiple estimates including the observations and the results of top-down atmospheric carbon dioxide (CO2) inversions and bottom-up dynamic global vegetation models. With this in view, this study synthesizes the carbon source/sink due to net ecosystem productivity (NEP), land cover land use change (ELUC), fires and fossil burning (EFIRE) for the South Asia (SA), Southeast Asia (SEA) and South and Southeast Asia (SSEA=SA+SEA) and each country in these regions using the multiple top-down and bottom-up modeling results. The terrestrial net biome productivity (NBP=NEP-ELUC-EFIRE) calculated based on bottom-up models in combination with EFIRE based on GFED4s data show net carbon sinks of 217±147, 10±55, and 227±279 TgC yr?1 for SA, SEA, and SSEA. The top-down models estimated NBP net carbon sinks were 20±170, 4±90 and 24±180 TgC yr?1. In comparison, regional emissions from the combustion of fossil fuels were 495, 275, and 770 TgC yr?1, which are many times higher than the NBP sink estimates, suggesting that the contribution of the fossil fuel emissions to the carbon budget of SSEA results in a significant net carbon source during the 2000s. When considering both NBP and fossil fuel emissions for the individual countries within the regions, Bhutan and Laos were net carbon sinks and rest of the countries were net carbon source during the 2000s. The relative contributions of each of the fluxes (NBP, NEP, ELUC, and EFIRE, fossil fuel emissions) to a nation’s net carbon flux varied greatly from country to country, suggesting a heterogeneous dominant carbon fluxes on the country-level throughout SSEA

    Regional Carbon Fluxes from Land Use and Land Cover Change in Asia, 1980-2009

    Get PDF
    We present a synthesis of the land-atmosphere carbon flux from land use and land cover change (LULCC) in Asia using multiple data sources and paying particular attention to deforestation and forest regrowth fluxes. The data sources are quasi-independent and include the U.N. Food and Agriculture Organization-Forest Resource Assessment (FAO-FRA 2015; country-level inventory estimates), the Emission Database for Global Atmospheric Research (EDGARv4.3), the 'Houghton' bookkeeping model that incorporates FAO-FRA data, an ensemble of 8 state-of-the-art Dynamic Global Vegetation Models (DGVM), and 2 recently published independent studies using primarily remote sensing techniques. The estimates are aggregated spatially to Southeast, East, and South Asia and temporally for three decades, 1980–1989, 1990-1999 and 2000-2009. Since 1980, net carbon emissions from LULCC in Asia were responsible for 20%-40% of global LULCC emissions, with emissions from Southeast Asia alone accounting for 15%-25% of global LULCC emissions during the same period. In the 2000s and for all Asia, three estimates (FAO-FRA, DGVM, Houghton) were in agreement of a net source of carbon to the atmosphere, with mean estimates ranging between 0.24 to 0.41 Pg C yr?1, whereas EDGARv4.3 suggested a net carbon sink of ?0.17 Pg C yr?1. Three of 4 estimates suggest that LULCC carbon emissions declined by at least 34% in the preceding decade (1990-2000). Spread in the estimates is due to the inclusion of different flux components and their treatments, showing the importance to include emissions from carbon rich peatlands and land management, such as shifting cultivation and wood harvesting, which appear to be consistently underreported

    Neonatal Ventilator Associated Pneumonia: A Quality Improvement Initiative Focusing on Antimicrobial Stewardship

    Get PDF
    Background and Aims: Neonatal ventilator associated pneumonia (VAP) is a common nosocomial infection and a frequent reason for empirical antibiotic therapy in NICUs. Nonetheless, there is no international consensus regarding diagnostic criteria and management. In a first step, we analyzed the used diagnostic criteria, risk factors and therapeutic management of neonatal VAP by a literature review. In a second step, we aimed to compare suspected vs. confirmed neonatal VAP episodes in our unit according to different published criteria and to analyze interrater-reliability of chest x-rays. Additionally, we aimed to evaluate the development of VAP incidence and antibiotic use after implementation of multifaceted quality improvement changes regarding antimicrobial stewardship and infection control (VAP-prevention-bundle, early-extubation policy, antimicrobial stewardship rounds).Methods: Neonates until 44 weeks of gestation with suspected VAP, hospitalized at our level-III NICU in Lucerne from September 2014 to December 2017 were enrolled. VAP episodes were analyzed according to 4 diagnostic frameworks. Agreement regarding chest x-ray interpretation done by 10 senior physicians was assessed. Annual incidence of suspected and confirmed neonatal VAP episodes and antibiotic days were calculated and compared for the years 2015, 2016, and 2017.Results: 17 studies were identified in our literature review. Overall, CDC-guidelines or similar criteria, requesting radiographic changes as main criteria, are mostly used. Comparison of suspected vs. confirmed neonatal VAP episodes showed a great variance (20.4 vs. 4.5/1,000 ventilator-days). The interrater-reliability of x-ray interpretation was poor (intra-class correlation 0.25). Implemented changes resulted in a gradual decline in annual VAP incidence and antibiotic days from 2015 compared with 2017 (28.8 vs. 7.4 suspected episodes/1,000 ventilator-days, 5.5 vs. 0 confirmed episodes/1,000 ventilator-days and 211 vs. 34.7 antibiotic days/1,000 ventilation-days, respectively).Conclusion: The incidence of suspected VAP and concomitant antibiotic use is much higher than for confirmed VAP, therefore inclusion of suspected episodes should be considered for accurate evaluation. There is a high diagnostic inconsistency and a low reliability of interpretation of chest x-rays regarding VAP. Implementation of combined antimicrobial stewardship and infection control measures may lead to an effective decrease in VAP incidence and antibiotic use

    Earth Virtualization Engines -- A Technical Perspective

    Full text link
    Participants of the Berlin Summit on Earth Virtualization Engines (EVEs) discussed ideas and concepts to improve our ability to cope with climate change. EVEs aim to provide interactive and accessible climate simulations and data for a wide range of users. They combine high-resolution physics-based models with machine learning techniques to improve the fidelity, efficiency, and interpretability of climate projections. At their core, EVEs offer a federated data layer that enables simple and fast access to exabyte-sized climate data through simple interfaces. In this article, we summarize the technical challenges and opportunities for developing EVEs, and argue that they are essential for addressing the consequences of climate change

    Attribution of extreme precipitation in the lower reaches of the Yangtze River during May 2016

    Get PDF
    May 2016 was the third wettest May on record since 1961 over central eastern China based on station observations, with total monthly rainfall 40% more than the climatological mean for 1961–2013. Accompanying disasters such as waterlogging, landslides and debris flow struck part of the lower reaches of the Yangtze River. Causal influence of anthropogenic forcings on this event is investigated using the newly updated Met Office Hadley Centre system for attribution of extreme weather and climate events. Results indicate that there is a significant increase in May 2016 rainfall in model simulations relative to the climatological period, but this increase is largely attributable to natural variability. El Ni ̃no years have been found to be correlatedwith extreme rainfall in the Yangtze River region in previous studies—the strong El Ni ̃no of 2015–2016 may account for the extreme precipitation event in 2016. However, on smaller spatial scales we find that anthropogenic forcing has likely played a role in increasing the risk of extreme rainfall to the north of the Yangtze and decreasing it to the south

    Global wetland contribution to 2000-2012 atmospheric methane growth rate dynamics

    Get PDF
    Increasing atmospheric methane (CH4) concentrations have contributed to approximately 20% of anthropogenic climate change. Despite the importance of CH4 as a greenhouse gas, its atmospheric growth rate and dynamics over the past two decades, which include a stabilization period (1999–2006), followed by renewed growth starting in 2007, remain poorly understood. We provide an updated estimate of CH4 emissions from wetlands, the largest natural global CH4 source, for 2000–2012 using an ensemble of biogeochemical models constrained with remote sensing surface inundation and inventory-based wetland area data. Between 2000–2012, boreal wetland CH4 emissions increased by 1.2 Tg yr−1 (−0.2–3.5 Tg yr−1), tropical emissions decreased by 0.9 Tg yr−1 (−3.2−1.1 Tg yr−1), yet globally, emissions remained unchanged at 184 ± 22 Tg yr−1. Changing air temperature was responsible for increasing high-latitude emissions whereas declines in low-latitude wetland area decreased tropical emissions; both dynamics are consistent with features of predicted centennial-scale climate change impacts on wetland CH4 emissions. Despite uncertainties in wetland area mapping, our study shows that global wetland CH4 emissions have not contributed significantly to the period of renewed atmospheric CH4 growth, and is consistent with findings from studies that indicate some combination of increasing fossil fuel and agriculture-related CH4 emissions, and a decrease in the atmospheric oxidative sink

    Mitochondrial physiology

    Get PDF
    As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery
    • 

    corecore