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Abstract The Primordial Inflation Explorer (PIXIE) is an Explorer-class mission concept to measure the energy spectrum and linear polarization of the cosmic microwave background (CMB). A single cryogenic Fourier transform spectrometer compares the sky to an external blackbody calibration target, measuring the Stokes I, Q, U parameters to levels ∼200 Jy/sr in each 2.65° diameter beam over the full sky, in each of 300 frequency channels from 28 GHz to 6 THz. With sensitivity over 1000 times greater than COBE/FIRAS, PIXIE opens a broad discovery space for the origin, contents, and evolution of the universe. Measurements of small distortions from a CMB blackbody spectrum provide a robust determination of the mean electron pressure and temperature in the universe while constraining processes including dissipation of primordial density perturbations, black holes, and the decay or annihilation of dark matter. Full-sky maps of linear polarization measure the optical depth to reionization at nearly the cosmic variance limit and constrain models of primordial inflation. Spectra with sub-percent absolute calibration spanning microwave to far-IR wavelengths provide a legacy data set for analyses including line intensity mapping of extragalactic emission and the cosmic infrared background amplitude and anisotropy. We describe the PIXIE instrument sensitivity, foreground subtraction, and anticipated science return from both the baseline 2-year mission and a potential extended mission.

Gas turbine (GT) power plants operating in arid climates suffer a decrease in output power during the hot summer months because of insufficient cooling. Cooling the air intake to the compressor has been widely used to mitigate this shortcoming. An energy analysis of a GT Brayton cycle coupled to a refrigeration cycle shows a promise for increasing the output power with a little decrease in thermal efficiency. A thermo-economics algorithm is developed and applied to an open cycle, Hitachi MS700 GT plant at the industrial city of Yanbu by the Red Sea in the Kingdom of Saudi Arabia. Result shows that the enhancement in output power depends on the degree of chilling the air intake to the compressor (a 12 - 22 K decrease is achieved). For this case study, maximum power gain ratio (PGR) is 15.46%, at a decrease in thermal efficiency of 12.25%. The cost of adding the air cooling system is also investigated and a cost function is derived that incorporates time-dependent meteorological data, operation characteristics of the GT and the air intake cooling system and other relevant parameters such as interest rate, lifetime, and operation and maintenance costs. The profit of adding the air cooling system is calculated for different electricity tariff.

La présente recherche étudie la viabilité technico-économique de deux cas de systèmes énergétiques hybrides pour des solutions énergétiques durables dans une zone urbaine connue pour son ensoleillement abondant. Ces cas impliquent des combinaisons de photovoltaïque (PV) et de biomasse, avec des composants supplémentaires tels qu'un électrolyseur et une pile à combustible (FC). Le cas 1 comprend le PV/biomasse/électrolyseur, tandis que le cas 2 comprend le PV/biomasse/pile à combustible/électrolyseur/batterie, visant à produire de l'électricité et de l'hydrogène. Cet article a analysé les demandes d'énergie industrielle pendant les périodes hors saison, de mi-saison et de haute saison. Le système optimal pour le cas 2 est le plus fiable avec un panneau photovoltaïque de 23645 kW, un générateur de biogaz de 3800 kW, un convertisseur de 3821 kW, une pile à combustible de 250 kW, un électrolyseur de 600 kW, un réservoir de stockage d'hydrogène de 600 kg (Htank) et un système de secours de 30 batteries avec une stratégie d'envoi CC pour les consommateurs hors saison. Pour les utilisateurs en haute saison, le système dispose de 23789 kW de panneaux photovoltaïques, de 3800 kW de générateurs de biogaz, de 3861 kW de convertisseurs, de 250 kW de FC, de 1000 kW d'électrolyseur, de 1000 kg de Htank et de 30 batteries de réserve avec un plan d'expédition LF. Les résultats de la recherche suggèrent que l'utilisation de PV/biomasse/FC/électrolyseur/batterie est une stratégie plus réalisable et économique en raison des avantages du système. L'augmentation estimée du LCOE a été causée par la hausse du taux d'actualisation et des prix du carburant. La presente investigación investiga la viabilidad tecno-económica de dos casos de sistemas de energía híbrida para soluciones energéticas sostenibles en una zona urbana conocida por su abundante luz solar. Estos casos involucran combinaciones de energía fotovoltaica (PV) y biomasa, con componentes adicionales como un electrolizador y una celda de combustible (FC). El caso 1 comprende PV/biomasa/electrolizador, mientras que el caso 2 incluye PV/biomasa/pila de combustible/electrolizador/batería, con el objetivo de producir electricidad e hidrógeno. Este documento analizó las demandas de energía industrial en los períodos de temporada baja, media y alta. El sistema óptimo para el caso 2 es el más fiable con un panel fotovoltaico de 23645 kW, un generador de biogás de 3800 kW, un convertidor de 3821 kW, una pila de combustible de 250 kW, un electrolizador de 600 kW, un tanque de almacenamiento de hidrógeno de 600 kg (Htank) y un sistema de respaldo de 30 baterías con una estrategia de envío de CC para consumidores fuera de temporada. Para los usuarios de temporada alta, el sistema cuenta con 23789 kW de paneles fotovoltaicos, 3800 kW de generadores de biogás, 3861 kW de convertidores, 250 kW de FC, 1000 kW de electrolizador, 1000 kg de Htank y 30 bancos de salas de respaldo de baterías con un plan de despacho LF. Los resultados de la investigación sugieren que la utilización de PV/biomasa/FC/electrolizador/batería es una estrategia más factible y económica debido a los beneficios del sistema. El aumento estimado en el LCOE fue causado por el aumento de la tasa de descuento y los precios del combustible. The present research investigates the techno-economic viability of two cases of hybrid energy systems for sustainable energy solutions in an urban area known for its abundant sunlight. These cases involve combinations of photovoltaic (PV) and biomass, with additional components such as an electrolyzer and fuel cell (FC). Case 1 comprises PV/biomass/electrolyzer, while Case 2 includes PV/biomass/fuel cell/electrolyzer/battery, aiming to produce electricity and hydrogen. This paper analyzed industrial power demands across off-season, middle-season, and peak-season periods. The optimal system for case 2 is the most reliable one with a 23645-kW PV panel, a 3800-kW biogas generator, a 3821-kW converter, a 250-kW fuel cell, a 600-kW electrolyzer, a 600-kg hydrogen storage tank (Htank), and a 30-battery backup system with a CC send-off strategy for off-season consumers. For peak-season users, the system has 23789-kW of PV panels, 3800-kW of biogas generators, 3861-kW of converters, 250-kW of FC, 1000-kW of electrolyzer, 1000-kg of Htank, and 30 battery backup room banks with an LF dispatch plan. The research findings suggest that utilizing PV/biomass/FC/electrolyzer/battery is a more feasible and economical strategy due to system benefits. The estimated increase in the LCOE was caused by the rising discount rate and fuel prices. يبحث البحث الحالي في الجدوى التقنية والاقتصادية لحالتين من أنظمة الطاقة الهجينة لحلول الطاقة المستدامة في منطقة حضرية معروفة بأشعة الشمس الوفيرة. تتضمن هذه الحالات مجموعات من الخلايا الكهروضوئية (PV) والكتلة الحيوية، مع مكونات إضافية مثل المحلل الكهربائي وخلية الوقود (FC). تشتمل الحالة 1 على PV/الكتلة الحيوية/المحلل الكهربائي، بينما تتضمن الحالة 2 PV/الكتلة الحيوية/خلية الوقود/المحلل الكهربائي/البطارية، بهدف إنتاج الكهرباء والهيدروجين. حللت هذه الورقة متطلبات الطاقة الصناعية خلال فترات غير الموسم والموسم المتوسط وموسم الذروة. النظام الأمثل للحالة 2 هو الأكثر موثوقية مع لوحة PV 23645 - kW، ومولد غاز حيوي 3800 - kW، ومحول 3821 - kW، وخلية وقود 250 - kW، ومحلل كهربائي 600 - kW، وخزان تخزين هيدروجين 600 - kg (Htank)، ونظام نسخ احتياطي 30 بطارية مع استراتيجية إرسال CC للمستهلكين خارج الموسم. بالنسبة لمستخدمي موسم الذروة، يحتوي النظام على 23789 كيلو واط من الألواح الكهروضوئية، و 3800 كيلو واط من مولدات الغاز الحيوي، و 3861 كيلو واط من المحولات، و 250 كيلو واط من FC، و 1000 كيلو واط من المحلل الكهربائي، و 1000 كجم من Htank، و 30 بنك غرفة بطارية احتياطية مع خطة إرسال LF. تشير نتائج البحث إلى أن استخدام الكهروضوئية/الكتلة الحيوية/FC/المحلل الكهربائي/البطارية هو استراتيجية أكثر جدوى واقتصادية بسبب فوائد النظام. كانت الزيادة المقدرة في LCOE ناتجة عن ارتفاع معدل الخصم وأسعار الوقود.

International audience; The wind energy, as a kind of renewable energy resources, has the potential to replace traditional fossil fuels. However, its intermittent power output can incur frequency instability due to the instantaneous unbalance between power generation and load demand. To smooth the penetration of wind energy, this paper presents a robust cooperative load frequency control (LFC) strategy for multi-area power systems, which is a hierarchical control approach. For the low-level wind turbine control, this paper adopts model predictive control (MPC) method to achieve the rated wind power tracking. In the meantime, an improved event-triggered scheme (ETS) considering multiple historic released signals is employed to relieve the computational burden of MPC. For the high-level cooperative LFC, this paper incorporates the robust performance index in the control synthesis to suppress the impact of intermittent wind power on frequency stability. In addition, to address the underlying shift of the steady-state operating point caused by the intermittent wind power supply, this paper improves the commonly used small-signal LFC model by adding an uncertain matrix, which reasonably explains the possible change of system parameters and extends the applicability of the traditional LFC model. Simulations are done on a four-area power system, and the results verify the efficacy of the presented event-triggered scheme and the robust cooperative LFC approach. Note to Practitioners —To promote the penetration of wind energy into power systems, this work explores a robust cooperative LFC approach under multi-agent structure to ensure the stability of the system, aiming at extending the applicability of existing approaches. The proposed approach is hierarchical. At the rated wind power tracking level, the MPC is employed to handle constraints associated with actuating devices, such as heterogeneous convertors. Simultaneously, an improved ETS considering multiple historic triggered signals is integrated in the MPC to reduce the computational burden. At the power system level, the robust performance index is incorporated in the control design to smooth the impacts of intermittent wind power on frequency stability. Additionally, the study accounts for the potential shift of the steady-state operating point and improves the traditional small-signal LFC model by adding an uncertain matrix, which can better explain the variation of system parameters and is more applicable in practical power system engineering. Simulation results demonstrate that the proposed robust cooperative LFC approach can effectively maintain the system frequency within the admissible range under the high penetration of wind energy, whereas the traditional PI controller falls short in this regard.

With the integration of a large number of microgrids in the power distribution network operation, economic and strategic challenges arise. To address these challenges, this research provides a comprehensive investigation into the operational, economic, and strategic dynamics of microgrids. Through careful data analysis, the study interprets the complications of microgrid responses to seasonal changes. It also investigates energy consumption patterns and production dynamics. The detailed analysis of microgrid configurations reveals the unique attributes and challenges of PV, wind, and hydropower microgrids. Moreover, the research explains the financial implications of microgrid integration, from setup costs to potential ROI. It is also examining the cooperative relationship between microgrids and conventional grids. Key findings highlight that solar microgrids contribute 3.2% to 5.3%, wind microgrids provide 5.9% to 7.4%, and hydropower microgrids contribute 24.4% of total power. Energy purchase peaks at 850,000 kWh in August and declines to 580,000 kWh in May. 170,000 kWh of energy is sold back to the grid in May. Moreover, the grid energy costs reduced from $0.178 kWh to $0.30 kWh. The total net present cost of the system is achieved at $37,880,023.33. Renewable energy production ranges from 480 kW to 2,300 kW, with a penetration level reaching 160%.

Abstract Green hydrogen is critical for decarbonizing hard-to-electrify sectors, but it faces high costs and investment risks. Here we define and quantify the green hydrogen ambition and implementation gap, showing that meeting hydrogen expectations will remain challenging despite surging announcements of projects and subsidies. Tracking 190 projects over 3 years, we identify a wide 2023 implementation gap with only 7% of global capacity announcements finished on schedule. In contrast, the 2030 ambition gap towards 1.5 °C scenarios has been gradually closing as the announced project pipeline has nearly tripled to 422 GW within 3 years. However, we estimate that, without carbon pricing, realizing all these projects would require global subsidies of US$1.3 trillion (US$0.8–2.6 trillion range), far exceeding announced subsidies. Given past and future implementation gaps, policymakers must prepare for prolonged green hydrogen scarcity. Policy support needs to secure hydrogen investments, but should focus on applications where hydrogen is indispensable.

In order to solve the problem of excessive burden of electricity and energy consumption in urban landscape buildings clusters, the study combined data mining algorithms to establish a prediction model for energy-saving renovation of urban landscape building clusters. Firstly, the energy demand and energy consumption of theurban landscape buildings complex were analysed, a mathematical model was established to predict the energy consumption of the building complex. Then, the prediction model of energy-saving retrofitting of building clusters was constructed by combining data mining techniques. The experimental results show that the change trend of total energy consumption is different under different single influencing factors of energy consumption. Among them, the lighting power density factor has the greatest influence on energy consumption, and its annual energy consumption change rate can reach about 0.35. Applying the prediction model to the energy consumption prediction of 15 urban single buildings, it was found that the total energy consumption of the buildings before the retrofit was much higher than that after the retrofit, and the energy-saving rate of the whole observed sample building group was as high as 18.5%, meanwhile, the highest energy-saving rate of the single buildings reached 30.1%.