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AbstractThe United States (U.S.) West Coast power system is strongly influenced by variability and extremes in air temperatures (which drive electricity demand) and streamflows (which control hydropower availability). As hydroclimate changes across the West Coast, a combination of forces may work in tandem to make its bulk power system more vulnerable to physical reliability issues and market price shocks. In particular, a warmer climate is expected to increase summer cooling (electricity) demands and shift the average timing of peak streamflow (hydropower production) away from summer to the spring and winter, depriving power systems of hydropower when it is needed the most. Here, we investigate how climate change could alter interregional electricity market dynamics on the West Coast, including the potential for hydroclimatic changes in one region (e.g., Pacific Northwest (PNW)) to “spill over” and cause price and reliability risks in another (e.g., California). We find that the most salient hydroclimatic risks for the PNW power system are changes in streamflow, while risks for the California system are driven primarily by changes in summer air temperatures, especially extreme heat events that increase peak system demand. Altered timing and amounts of hydropower production in the PNW do alter summer power deliveries into California but show relatively modest potential to impact prices and reliability there. Instead, our results suggest future extreme heat in California could exert a stronger influence on prices and reliability in the PNW, especially if California continues to rely on its northern neighbor for imported power to meet higher summer demands.

This article describes various opportunities but also constraints to greater crop diversification, and the impact on local sustainability in the Khorezm province of Uzbekistan in the Aral Sea basin. At present, approximately 70% of the area in this study region is sown to irrigated cotton and winter wheat under the so-called state mandate. We present evidence of the benefits of moving away from this approach toward more diversified farming with an increasing area of alternative crops in the selected region. We report on a series of studies that included a) crop suitability screening based on secondary data, b) joint farmer experiments, and c) a mathematical simulation model with the overarching objective to assess potential benefits and constraints for crop diversification. The findings of this long-term, multiyear, and multidisciplinary approach show that greater crop diversity can increase water use efficiency, and secure farm income in dryland areas prone to water scarcity and soil salinity. In additio...

Abstract This paper reports flexible thermoelectric generators (TEGs) employing eutectic gallium indium (EGaIn) liquid metal interconnects encased in a novel, high thermal conductivity (HTC) elastomer. These TEGs are part of a broader effort to harvest thermal energy from the body and convert it into electrical energy to power wearable electronics. The flexible TEGs reported in this paper employ the same thermoelectric legs' used in rigid TEGs, thus eliminating the need to develop new materials specifically for flexible TEGs that often sacrifice the so-called figure of merit' for flexibility. Flexible TEGs reported here embed rigid thermoelectric legs' in soft and flexible packaging, using stretchable EGaIn interconnects. The use of liquid metal interconnects provides ultimate stretchability and low electrical resistance between the thermoelectric legs. The liquid metal lines are encased in a new stretchable silicone elastomer doped with both graphene nano-platelets and EGaIn to increase its thermal conductivity. This high thermal conductivity elastomer not only reduces the parasitic thermal resistance of the encapsulation layer but it also serves as a heat spreader, leading to 1.7X improvement in the output power density of TEGs compared to devices fabricated with a conventional elastomer. The device performance is further improved by a thin Cu layer acting as a heat spreader providing an additional 1.3X enhancement in the output power at 1.2 m/s air velocity (typical walking speed). Worn on the wrist, our best devices achieve power levels in excess of 30 μW/cm2 at an air velocity of 1.2 m/s outperforming previously reported flexible TEGs.

This paper examines for the first time the relationship between CO2 emissions and the consumption of renewable and non-renewable energy in Uzbekistan, spanning the period 1985-2020. The analysis uses the Autoregressive Distributed Lags (ARDL) model to estimate the long-run dynamic multipliers and short-run elasticity coefficients of energy consumption variables. Economic factors, such as GDP, are excluded in the analysis as they may cause multicollinearity problems. The empirical results document that in the short- and long-run, hydropower (renewable) energy consumption negatively impacts CO2 emissions per capita, showing a unidirectional causal effect. As regards with non-renewable energy consumption, natural gas and oil energy consumption have a positive impact on CO2 emissions per capita both in the short and long run. Coal consumption positively impacts CO2 emissions in the short run, while it is negative in the long run. Policy measures to enhance the collection of energy from additional renewable energy sources, in particular hydropower, should be taken into account in order to increase the share of renewable energy, and thus, to compensate non-renewable energy consumption which is the main contributor to CO2 emissions. Moreover, solar and wind energy should be explicitly taken into consideration as an additional renewable energy source, which has the lack of attention by policymakers. Furthermore, policy actions, such as the involvement of the private sector into renewable energy projects and the implementation of effective carbon tax policies, could be further options to reduce CO2 emissions.

Supplementing fossil fuels with solar air tempering for brooding young livestock could reduce energy use and improve indoor air quality. Metal transpired solar collectors (TSC) are effective but too expensive for heating livestock buildings. An inexpensive 12.7 m2 dark grey landscape-fabric-based transpired solar collector (fTSC) was evaluated in a swine nursery with two herds of pigs. A fraction of the fTSC area was underlain with phase change material (PCM) to store excess heat. The Test room with the fTSC was compared with an adjacent identical Control room, each with 120 piglets. The fTSC provided supplemental heating, e.g., with a suction velocity (Vs) of 0.027 m/s during a 9 h period, air temperature was increased by 11.6 °C (mean irradiance of 592 W/m2). Between 4 pm and 9 pm that same day, the PCM increased air temperature by 3.9 °C. The fTSC did not reduce propane use or improve pig performance. Higher Vs, operational changes and controller modifications could improve system performance and reduce cost. Modeling could be used to optimize PCM use. Hence, this very low-cost fabric-based solar air heater offers potential for considerable reduction in heat energy use in livestock barns.

Abstract Solar heat could displace fossil fuel to reduce energy cost for brooding livestock and poultry. A transpired solar collector (TSC), consisting of a perforated dark-colored metal surface, can provide considerable heating but metal TSCs (mTSCs) are expensive. Since a perforated black plastic sheet will be less-expensive, a plastic TSC (pTSC) was evaluated. The 1.49 m2 pTSC (porosity of 1.2%) supplemented a propane heater in a room housing 240 turkey poults; an adjacent room without a pTSC, with 240 poults was the control. Monitoring was performed over two flocks of poults. A custom-built controller bypassed the pTSC during nighttime or when the room did not require heating to bring in fresh air. The pTSC gave a maximum temperature rise of 25.4 °C at a solar irradiance (I) of 882 W/m2 and suction velocity (Vs) of 0.033 m/s over 15 min. Over 178 h of operation, with an average I of 668 ± 295 W/m2 and average Vs of 0.036 m/s, the pTSC increased air temperature by an average of 8.1 ± 4.2 °C. Probably due to higher ventilation rate and an oversized propane heater, propane use was not reduced in the Test room with the pTSC vs. the Control room. The Test room had lower CO2 and CO concentrations due to higher ventilation, which may have improved turkey performance. The metal TSC gave a slightly higher temperature rise at a lower Vs but the less-expensive pTSC could be a more cost-effective solar air heater that could readily be scaled up for agricultural and other applications in many parts of the world. Scale-up considerations seem feasible and are presented for a 10,000-poult brooder barn.

The burgeoning integration of distributed energy resources (DER) poses new challenges for the economic and safe operation of the electricity system. The current distribution-side policy is largely based on mandatory regulations and incentives, rather than the design of a competitive market mechanism to arouse DERs to freely compete in the retail market. To address this issue, we proposed a transactive retail market mechanism to attract the active participation of profit-driven DER retailers in a deregulated way. Considering the limited competitive property of the retail market, a bi-level DSO-dominated framework is constructed to simulate the virtual game between distribution system operator (DSO) and DER retailers. Specifically, the flexible interval pricing of retailers is modeled as a series of binary revenue constraints to influence the DSO's centralized economic dispatch decisions, where the time-varying distribution locational marginal price is adopted to settle energy activities at different locations over the time horizon. Due to the uncertain power flow path during the coordinated decision-making process, we proposed a general undirected second-order cone-based AC radial power flow model and provided sufficient conditions to ensure its exactness. Also, we applied a series of approximation and relaxation techniques to transform the bi-level mixed-integer quadratic framework with highly discrete induced domains into a solvable mixed-integer semidefinite programming problem. It is demonstrated in the case study that the proposed mechanism can not only improve market efficiency but also eliminate market power and the resulting market failures.

Coastal bermudagrass (Cynodon dactylon L.) may be a potentially important source of bio-based energy in the southern US due to its vast acreage. It is often produced as part of a waste management plan with varying nutrient composition and energy characteristics on fields irrigated with livestock wastewater. The objective of this study was to determine the effect of subsurface drip irrigation with treated swine wastewater on both the quantity and quality of bermudagrass bioenergy. The treated wastewater was recycled from an advanced treatment system and used for irrigation of bermudagrass in two crop seasons. The experiment had nine water and drip line spacing treatments arrayed in a randomized complete block-design with four replicates. The bermudagrass was analyzed for calorific and mineral contents. Bermudagrass energy yields for 2004 and 2005 ranged from 127.4 to 251.4MJ ha(-1). Compared to irrigation with commercial nitrogen fertilizer, the least biomass energy density was associated with bermudagrass receiving treated swine wastewater. Yet, in 2004 the wastewater irrigated bermudagrass had greater hay yields leading to greater energy yield per ha. This decrease in energy density of wastewater irrigated bermudagrass was associated with increased concentrations of K, Ca, and Na. After thermal conversion, these compounds are known to remain in the ash portion thereby decreasing the energy density. Nonetheless, the loss of energy density using treated effluent via SDI may be offset by the positive influence of these three elements for their catalytic properties in downstream thermal conversion processes such as promoting a lesser char yield and greater combustible gas formation.

Les montagnes abritent une part considérable de la population humaine. Environ un milliard de personnes vivent dans des zones montagneuses, qui abritent une riche diversité naturelle et socioculturelle. Aujourd'hui, de nombreuses personnes vivant dans des zones montagneuses du monde entier sont confrontées à des changements fondamentaux de leurs conditions de vie culturelles et économiques. Dans le même temps, les communautés de montagne ont défié les environnements difficiles dans le passé en s'adaptant aux conditions naturelles changeantes et en faisant preuve de niveaux remarquables de résilience. Dans cet article de synthèse, nous fournissons un aperçu complet de la littérature scientifique de langue anglaise sur les sujets liés à la résilience dans les zones de montagne sur la base d'une revue systématique de la base de données documentaire Scopus®. Nous proposons un point de départ structuré pour les interactions science-pratique et les activités concrètes basées sur l'action pour soutenir les moyens de subsistance et renforcer la résilience dans les zones de montagne. Nous suggérons que les lacunes existantes en matière de connaissances puissent être comblées en s'appuyant sur les connaissances locales et en co-créant des solutions avec les communautés. De cette façon, nous pouvons renforcer les capacités d'innovation et amortir activement l'impact des crises tout en soutenant la transformation délibérée vers la durabilité et la régénération pour améliorer davantage la résilience. Las montañas son el hogar de una parte considerable de la población humana. Alrededor de mil millones de personas viven en zonas montañosas, que albergan una rica diversidad natural y sociocultural. Hoy en día, muchas personas que viven en zonas montañosas de todo el mundo se enfrentan a cambios fundamentales en sus condiciones de vida culturales y económicas. Al mismo tiempo, las comunidades de montaña han desafiado los entornos hostiles en el pasado al adaptarse a las condiciones naturales cambiantes y mostrar niveles notables de resiliencia. En este documento de revisión, proporcionamos una descripción general completa de la literatura científica en inglés sobre temas relacionados con la resiliencia en áreas montañosas basada en una revisión sistemática de la base de datos de literatura Scopus®. Proponemos un punto de partida estructurado para las interacciones entre la ciencia y la práctica y actividades concretas basadas en la acción para apoyar los medios de vida y fortalecer la resiliencia en las zonas montañosas. Sugerimos que las brechas de conocimiento existentes se pueden abordar confiando en el conocimiento local y cocreando soluciones con las comunidades. De esta manera, podemos crear capacidad innovadora y amortiguar activamente el impacto de las crisis, al tiempo que apoyamos la transformación deliberada hacia la sostenibilidad y la regeneración para mejorar aún más la resiliencia. Mountains are home to a considerable share of the human population. Around a billion people live in mountainous areas, which harbor rich natural and sociocultural diversity. Today, many people living in mountainous areas worldwide face fundamental changes to their cultural and economic living conditions. At the same time, mountain communities have defied harsh environments in the past by adapting to changing natural conditions and showing remarkable levels of resilience. In this review paper, we provide a comprehensive overview of English-language scientific literature on resilience-related topics in mountain areas based on a systematic review of the Scopus® literature database. We propose a structured starting point for science–practice interactions and concrete action-based activities to support livelihoods and strengthen resilience in mountain areas. We suggest that existing knowledge gaps can be addressed by relying on local knowledge and cocreating solutions with communities. In this way, we can build innovative capacity and actively buffer against the impact of crises while supporting deliberate transformation toward sustainability and regeneration to further enhance resilience. الجبال هي موطن لنسبة كبيرة من السكان. يعيش حوالي مليار شخص في المناطق الجبلية، التي تضم تنوعًا طبيعيًا واجتماعيًا ثقافيًا غنيًا. اليوم، يواجه العديد من الأشخاص الذين يعيشون في المناطق الجبلية في جميع أنحاء العالم تغييرات جوهرية في ظروفهم المعيشية الثقافية والاقتصادية. وفي الوقت نفسه، تحدت المجتمعات الجبلية البيئات القاسية في الماضي من خلال التكيف مع الظروف الطبيعية المتغيرة وإظهار مستويات ملحوظة من المرونة. في ورقة المراجعة هذه، نقدم نظرة عامة شاملة على الأدبيات العلمية باللغة الإنجليزية حول الموضوعات المتعلقة بالمرونة في المناطق الجبلية بناءً على مراجعة منهجية لقاعدة بيانات أدبيات Scopus®. نقترح نقطة انطلاق منظمة للتفاعلات بين العلوم والممارسات والأنشطة العملية الملموسة لدعم سبل العيش وتعزيز القدرة على الصمود في المناطق الجبلية. نقترح أنه يمكن معالجة الفجوات المعرفية الحالية من خلال الاعتماد على المعرفة المحلية وإيجاد حلول مشتركة مع المجتمعات. وبهذه الطريقة، يمكننا بناء قدرات مبتكرة والوقاية بنشاط من تأثير الأزمات مع دعم التحول المتعمد نحو الاستدامة والتجديد لزيادة تعزيز المرونة.

Abstract Transpired solar collector (TSC) ducts were installed at a swine nursery and a turkey brooder farm in eastern North Carolina (NC), USA. Each farm had a Test (TSC duct-equipped) and an identical, adjacent Control treatment. Five swine herds and six turkey brooder flocks were monitored over two heating seasons (2010–2012). Propane uses were reduced by 55 and 27 L/m 2 -yr, respectively, in the swine and turkey barns; reductions were highly variable among herds or flocks and the modest reductions were due to warm weather and use of attic ventilation. Over a 14-d period, both the swine and turkey TSC units increased ambient temperature in the barns by ∼6 °C with a maximum increase of 22.5 °C in the turkey TSC. In the swine and turkey houses, calculated energy additions by the TSC were 433 and 81 MJ/yr-m 2 of collector surface area, or 16 and 3 L/m 2 , respectively, of propane saved. Calculated propane savings were much lower than measured values. Short-term efficiencies were higher in the swine TSC (>61%) vs. the turkey TSC (39–50%) probably due to the lower face velocity of the turkey TSC which increased collector heat losses. While barn CO 2 , RH, and temperature values were unaffected by the TSC, it was unclear why animal performance in the Test treatment was better. Simple payback periods for the TSC ducts at both farms were favorable (