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The interaction of severe weather, overhead lines and surrounding trees is the leading cause of outages to electric distribution networks in forested areas. In this paper, we show how utility-specific infrastructure and land cover data, aggregated around overhead lines, can improve outage predictions for Eversource Energy (formerly Connecticut Light and Power), the largest electric utility in Connecticut. Eighty-nine storms from different seasons (cold weather, warm weather, transition months) in the period 2005–2014, representing varying types (thunderstorms, blizzards, nor’easters, hurricanes) and outage severity, were simulated using the Weather Research and Forecasting (WRF) atmospheric model. WRF simulations were joined with utility outage data to calibrate four types of models: a decision tree (DT), random forest (RF), boosted gradient tree (BT) and an ensemble (ENS) decision tree regression that combined predictions from DT, RF and BT. The study shows that the ENS model forced with weather, infrastructure and land cover data was superior to the other models we evaluated, especially in terms of predicting the spatial distribution of outages. This framework could be used for predicting outages to other types of critical infrastructure networks with benefits for emergency-preparedness functions in terms of equipment staging and resource allocation.

Abstract In order to improve the accuracy, validity, reliability and reproducibility of reported power conversion efficiencies for solar cells, the journal, Solar Energy Materials and Solar Cells (SOLMAT), wishes to define how power conversion efficiencies should be reported. This expands upon what is specified in our Guide for Authors. This editorial also serves as a guide on how efficiency data should be checked within the reporting laboratory before sending cells or materials for testing at an independent laboratory. The threshold where the accuracy of efficiency values is important to the journal is whenever power conversion efficiencies require external quantum efficiencies (EQE) values above 50% over a large range of wavelengths or when reported power conversion efficiencies exceed 2.5%. Extra care should be taken in submitted manuscripts to document the measurement's quality, relevance and independent verification.

En los países del sur de Asia, incluidos Bangladesh, India y Pakistán, el escenario energético actual se considera no sostenible debido a diversas cuestiones, como las opciones económicas, ambientales, geopolíticas y tecnológicas para la explotación de la energía y el volumen insignificante del comercio regional de energía. Sin embargo, dentro de la región, India está liderando una fase de transición energética y transformación económica a través del desarrollo de energías renovables. Los países deben mostrar buenos resultados en el desarrollo de sus fuentes renovables siguiendo el rápido ritmo de las energías renovables en todo el mundo. Este artículo ofrece una visión general del escenario energético, el crecimiento de las energías renovables, la evolución y el enfoque de la política energética al resaltar los desafíos y barreras clave para la combinación energética ecológica de los países. Es importante destacar que el documento evalúa la combinación energética actual en el sur de Asia, destacando la anomalía de sus perspectivas futuras basadas en combustibles fósiles, sus ambiciones de avanzar hacia una menor contaminación ambiental y una combinación energética sostenible a través de un análisis FODA de herramientas estratégicas; fortalezas, debilidades, oportunidades y amenazas (FODA). En particular, este estudio examina las políticas gubernamentales para expandir la implementación de fuentes renovables con una visión de la estructura regulatoria existente del sector energético. Los hallazgos de la investigación presentada sugieren que para lograr el ambicioso objetivo de reducir la descarga de emisiones hasta en un 30% para el año 2030 en el marco de las Contribuciones Previstas Determinadas a Nivel Nacional (INDC), los gobiernos de los tres países deben tomar medidas preventivas. Incluye la reducción gradual de los subsidios a los combustibles fósiles, la integración del mercado dentro de la región y la rápida realización de las iniciativas existentes a través de una fuerte voluntad política, una buena gobernanza, la adopción de las últimas tecnologías y un plan de acción pragmático, y la cooperación energética en toda la región. Dans les pays d'Asie du Sud, y compris le Bangladesh, l'Inde et le Pakistan, le scénario énergétique actuel est considéré comme non durable en raison de divers problèmes tels que les options économiques, environnementales, géopolitiques et technologiques pour l'exploitation de l'énergie et le volume négligeable du commerce régional de l'énergie. Bien que, dans la région, l'Inde mène une phase de transition énergétique et de transformation économique grâce au développement des énergies renouvelables. Les pays doivent bien montrer dans le développement de leurs sources renouvelables à la suite du rythme rapide des énergies renouvelables dans le monde entier. Cet article offre un aperçu du scénario énergétique, de la croissance des énergies renouvelables, de l'évolution et de l'approche de la politique énergétique en soulignant les principaux défis et obstacles pour le mix énergétique écologique des pays. Il est important de noter que le document évalue le bouquet énergétique actuel en Asie du Sud, en soulignant l'anomalie de ses perspectives d'avenir basées sur les combustibles fossiles, ses ambitions de réduire la pollution environnementale et son bouquet énergétique durable grâce à une analyse SWOT d'outil stratégique ; forces, faiblesses, opportunités et menaces (SWOT). En particulier, cette étude examine les politiques gouvernementales visant à étendre la mise en œuvre des sources renouvelables avec un aperçu de la structure réglementaire existante du secteur de l'énergie. Les résultats de recherche présentés suggèrent que pour atteindre l'objectif ambitieux de réduire les rejets d'émissions jusqu'à 30 % d'ici 2030 dans le cadre des contributions prévues déterminées au niveau national (CPDN), les gouvernements des trois pays doivent prendre des mesures préventives. Il comprend la réduction progressive des subventions sur les combustibles fossiles, l'intégration du marché dans la région et la réalisation rapide des initiatives existantes grâce à une forte volonté politique, à une bonne gouvernance, à l'adoption des dernières technologies, à un plan d'action pragmatique et à une coopération énergétique dans toute la région. In the South Asian countries, including Bangladesh, India, and Pakistan, the current energy scenario is considered non-sustainable due to diverse issues such as economic, environmental, geopolitical, technological options for energy exploitation, and negligible volume of regional energy trade. Though, within the region, India is leading a phase of energy transition and economic transformation through renewable energy development. The countries need to exhibit well in the development of their renewable sources following the rapid pace of renewable energies worldwide. This article offers an overview of the energy scenario, growth of renewable energies, evolution, and approach for energy policy by highlighting key challenges and barriers for the ecological energy mix of the countries. Importantly, the paper assesses the current energy mix in South Asia, highlighting the anomaly of its fossil fuel-based future outlook, its ambitions to move towards less environmental pollution, and sustainable energy mix through a strategic tool SWOT analysis; strengths, weaknesses, opportunities, and threats (SWOT). In particular, this study examines the government policies to expand the implementation of renewable sources with an insight into the existing regulatory structure of the energy sector. The presented research findings suggest that to achieve the ambitious target to reduce emission discharge by up to 30% by the year 2030 under Intended Nationally Determined Contributions (INDCs), the Governments of the three countries must take preemptive measures. It includes the stage-wise reduction of subsidies on fossil fuels, market integration within the region, and swift realization of the existing initiatives through strong political will, good governance, adoption of the latest technologies, and a pragmatic action plan, and energy cooperation across the region. في بلدان جنوب آسيا، بما في ذلك بنغلاديش والهند وباكستان، يعتبر سيناريو الطاقة الحالي غير مستدام بسبب قضايا متنوعة مثل الخيارات الاقتصادية والبيئية والجيوسياسية والتكنولوجية لاستغلال الطاقة، وحجم ضئيل من تجارة الطاقة الإقليمية. على الرغم من أن الهند، داخل المنطقة، تقود مرحلة انتقال الطاقة والتحول الاقتصادي من خلال تطوير الطاقة المتجددة. تحتاج البلدان إلى أن تظهر أداءً جيدًا في تطوير مصادرها المتجددة بعد الوتيرة السريعة للطاقات المتجددة في جميع أنحاء العالم. تقدم هذه المقالة لمحة عامة عن سيناريو الطاقة، ونمو الطاقات المتجددة، والتطور، ونهج سياسة الطاقة من خلال تسليط الضوء على التحديات والحواجز الرئيسية لمزيج الطاقة البيئية للبلدان. والأهم من ذلك، تقوم الورقة بتقييم مزيج الطاقة الحالي في جنوب آسيا، مع تسليط الضوء على الشذوذ في توقعاتها المستقبلية القائمة على الوقود الأحفوري، وطموحاتها للتحرك نحو تلوث بيئي أقل، ومزيج الطاقة المستدامة من خلال تحليل SWOT الاستراتيجي للأداة ؛ نقاط القوة والضعف والفرص والتهديدات (SWOT). على وجه الخصوص، تبحث هذه الدراسة في السياسات الحكومية لتوسيع تنفيذ مصادر الطاقة المتجددة مع نظرة ثاقبة على الهيكل التنظيمي الحالي لقطاع الطاقة. تشير نتائج البحث المقدمة إلى أنه لتحقيق الهدف الطموح المتمثل في الحد من تصريف الانبعاثات بنسبة تصل إلى 30 ٪ بحلول عام 2030 بموجب المساهمات المقررة المحددة وطنيًا (INDCs)، يجب على حكومات البلدان الثلاثة اتخاذ تدابير وقائية. ويشمل ذلك التخفيض التدريجي للإعانات على الوقود الأحفوري، وتكامل الأسواق داخل المنطقة، والإدراك السريع للمبادرات القائمة من خلال الإرادة السياسية القوية، والحكم الرشيد، واعتماد أحدث التقنيات، وخطة عمل عملية، والتعاون في مجال الطاقة في جميع أنحاء المنطقة.

This paper studies a closed loop linear control system. The sensor computes a state estimate and sends it to the controller/actuator in the receiver block over a randomly fading packet dropping link. The receiver sends an ACK/NACK packet to the transmitter over a link. It is assumed that the transmission energy per packet at the sensor depletes a battery of limited capacity, replenished by an energy harvester. The objective is to design an optimal energy allocation policy and an optimal control policy so that a finite horizon LQG control cost is minimized. It is shown that in case the receiver to sensor feedback channel is free of errors, a separation principle holds. Hence, the optimal LQG controller is linear, the Kalman filter is optimal and the optimal energy allocation policy is obtained via solving a backward dynamic programming equation. In case the feedback channel is erroneous, the separation principle does not hold. In this case, we propose a suboptimal policy where the controller still uses a linear control, and the transmitter minimizes an expected sum of the trace of an “estimated” receiver state estimation error covariance matrix. Simulations are used to illustrate the relative performance of the proposed algorithms and various heuristic algorithms for both the perfect and imperfect feedback cases. It is seen that the dynamic programming based policies outperform the simple heuristic policies by a margin.

A major objective of the US Department of Energy is to increase coal utilization through the development of combustion stream cleanup technologies. Many of the existing cleanup devices as well as advanced concepts rely on heterogeneous processes (i.e., gas-solid interactions) to achieve efficient stream removal. Examples of such devices include particle injection and granular bed filters for alkali removal, limestone injection for SO/sub x/ removal in fluid bed combustors, dry injection for SO/sub x/removal in entrained combustion, and trace metal adsorption and removal on fly ash. Recent studies indicate that the successful use of turbines in combined cycle processes may depend on understanding the interaction between the gas phase alkali and particles in the combustion stream to substantially reduce turbine corrosion. This report documents progress in efforts to model the heterogeneous chemistry of coal combustion streams as well as laboratory studies to obtain critical input data for the report. 5 references, 15 figures.

This paper simulates the optimal day-ahead operation of energy storage in a power system with high wind penetration. Mixed integer programming is employed to formulate the optimal scheduling problem of a thermal based power system with energy storage as a centralized optimization. Simulation of the operation of a 10-generator power system with near-ideal storage is employed to identify the effects of energy storage on generation cost and conventional power plants. Simulation results show that implementation of energy storage reduces total energy generation costs for wind energy penetration levels up to 30%, while also reducing the variability in the output power of conventional generation units and wind energy spillage.

Abstract Lean gasoline engines offer greater fuel economy than common stoichiometric gasoline engines. However, excess oxygen prevents the use of the current three-way catalyst (TWC) to control nitrogen oxide (NOX) emissions in lean exhaust. A passive SCR concept, introduced by General Motors Global RD however, the rich operation necessary for NH3 production results in a fuel consumption penalty. The fuel penalty can be minimized by adjusting spark timing to increase rich-phase engine out NOX emissions and, thereby, NH3 levels. Additionally, higher engine out NOX during engine load increase to simulate acceleration resulted in additional fuel savings. A 10% fuel consumption benefit was achieved with the passive SCR approach by optimizing rich air-fuel equivalence ratio and spark timing while also utilizing acceleration load conditions.

Abstract The eddy covariance method was used to investigate carbon fluxes and evapotranspiration (ET) from a high biomass forage sorghum ( Sorghum bicolor L.) field in the Southern U.S. Great Plains for three growing seasons (2013–2015). Above normal precipitation and narrow row spacing (50 cm) led to higher biomass production (25 Mg ha −1 ) and leaf area index (LAI = 7.2) development in 2014. This also resulted in higher carbon uptake or net ecosystem production (NEP) and ET during that year. Early and late season precipitation enhanced ecosystem respiration (R eco ) resulting in lower NEP in 2015. Shorter growing season (119 days) also contributed to lower cumulative NEP in 2015. Estimated gross primary production (GPP) in 2014 (1780 g m −2 ) was 10% higher than the GPP in 2013 (1591 g m −2 ) and 24% higher than the GPP in 2015 (1353 g m −2 ). During all growing seasons, the site was a source of carbon (negative NEP) at the beginning and transitioned to a sink (positive NEP) later in the season. Biomass-GPP relationship indicated that approximately 65% of total GPP was allocated to above ground biomass (AGB). Average monthly ecosystem WUE (expressed as gross carbon gain per unit of ET) ranged from 1.7 g mm −1 to 4.2 g mm −1 . Results from our study indicate that weather conditions, growing season length and crop management are important factors in determining the magnitude of carbon uptake and release, and ET of this cellulosic biofuel feedstock crop in the Southern U.S. Great Plains.