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Errors in forecasting load and renewable-based generation in restructured power systems mean that independent system operators (ISOs) must procure sufficient operating reserves to keep the real-time operation of the system reliable and secure. But when procured reserves turn out to be insufficient in real-time due to the lack of resource capacity or ramp capability, operators often set higher prices for reserves and energy to encourage more supply, and to motivate consumers to decrease usage or shift it to other times. This procedure, which is called scarcity or shortage pricing, is a core feature of U.S. electricity markets. It is receiving increased attention from market designers and stakeholders because scarcity will become more important for spot price formation in the future with the increased penetration of zero-marginal cost renewables, and the shrinking role of fuel costs in setting prices. Scarcity pricing is implemented in various ways by different ISOs. These differences have practical implications for the level of prices and incentives for investment, operations, and demand modification. In this paper, general approaches and specific calculation procedures for reserve and energy scarcity pricing practices and calculations across the seven ISO-based U.S. power markets are reviewed and compared. A consistent terminology is used to facilitate the comparison. Current scarcity pricing practices are grouped into three approaches: (1) imposing an adder after the spot market is run; (2) including stepwise demand curves within market clearing procedures for non-contingency reserve products (e.g., the novel flexiramp product), which tends to yield longer right tails for energy scarcity premium curves; and (3) having stepwise demand curves for traditional contingency reserve products only, which results in shorter right tails in energy scarcity curves. A generic numerical example is presented to highlight the large practical differences among the reserve scarcity pricing approaches and specific implementations. To further investigate factors that contribute the most to demand curves differences among ISOs, a sensitivity analysis is performed. This analysis shows that the largest source of differences among the curves is the scarcity prices assumed in the case of severe scarcity, while the number of steps used and whether flexiramp is considered also yields important differences in scarcity prices. As renewable penetration increases, it will become increasingly crucial to employ administrative demand curves so that spot prices more effectively motivate supply and demand adjustments exactly when and where they are needed. This study shows that the different assumptions yield very different scarcity premiums for reserves and energy, and are likely to provide divergent incentives for resources to respond to shortages. It is concluded that to promote market efficiency, a reserve shortage demand curve should have at least three features: inclusion of the marginal value of reserve products at each shortage level, consideration of the magnitude and probability of supply contingencies, and avoidance of abrupt price discontinuities that can cause excessively volatile market outcomes. • Explains principles and specific calculation procedures for reserve scarcity pricing practices across U.S. power markets. • Proposes a novel classification of sources of penalty values applied in the markets, highlighting their relative advantages. • Presents a generic numerical example to illustrate practical differences among the reserve scarcity pricing approaches. • Performs a sensitivity analysis to further investigate the most significant factors in differences among ISO demand curves. • Makes recommendations for defining demand curves for reserve scarcity pricing that accurately reflect the value of reserves. [ABSTRACT FROM AUTHOR]

Buildings account for about 39% of the total energy consumption in the United States. Developing highly energy-efficient and environmentally friendly systems that are either actively or passively integrated into buildings plays a crucial role in decarbonizing the building sector. Among various technologies, desiccant-based energy systems have received particular attention in recent years due to their unique advantages, such as being thermally driven using low-grade waste or solar energies and being reliable over a wide range of operating ranges. Extensive research efforts have been exerted on desiccant-enabled technologies at both material and system levels aiming to increase their performance and achieve high technological readiness levels. The present review paper comprehensively discusses research works made at the system level. It overviews desiccant-based air conditioning systems, desiccant-based humidity pumps, desiccant-based thermal energy storage systems, and desiccant-based appliances. The study identifies challenges and opportunities to accelerate the commercialization of desiccant-enabled technologies. It is found that desiccant materials offer great promise to improve energy efficiency and functionality of future buildings through decoupling the latent and sensible cooling loads in air conditioning systems, humidity pumps integrated into building facades, and next-generation appliances. However, commercial viability and widespread acceptance of desiccant-based systems have been hampered by several major obstacles, including liquid and air flow mal-distribution and inferior thermo-physical properties of desiccant materials resulting in low ab/adsorption and regeneration rates and bulky/costly systems. • Review the desiccant-enabled technologies at the system level. • Traditional desiccants suffer from limited performance in low-humid climates. • Humidity pumps integrate desiccants into the building facade. • Desiccant materials are promising for clothes dryers and dishwashers. • Identify challenges facing the commercialization of desiccant-enabled technologies. [ABSTRACT FROM AUTHOR]

This paper analyzes the long-run relationship between biomass energy production and biomass energy consumption in the United States (US), over 1993M01-2022M08. For robustness reasons, it is employed the cointegration methodology to sustain the main findings in parallel with unit root tests of biomass energy surplus/deficit. The main results evidence a long-run equilibrium between biomass energy production and biomass energy consumption in the US conditioned by structural breaks. More precisely, those breaks can severally alter biomass energy sustainability, their importance being crucial in the US's policy design in the biomass sector. Policymakers in the US should take into account the structural changes for their adjustments in the biomass energy market when no long-run equilibrium between biomass energy production and the biomass energy consumption is evidenced. Otherwise, no policy corrections are needed as the long-run equilibrium is reached based on the market self-regulation mechanism. • Biomass energy is sustainable in the US. • Biomass energy sustainability is conditioned by structural changes. • No hysteresis is observed in biomass energy surplus/deficit. • Market of biomass energy has a self-regulation mechanism under sustainability assumption. [ABSTRACT FROM AUTHOR]

The United States has pledged to develop a 100% carbon-free electric power system by 2035 and a net-zero-emissions economy by 2050. While important advancements have been made in the scale, performance, and economics of clean energy technologies, meeting the nation's ambitious goals will not only require their deployment at scale, but also additional innovation and effective integration of different solutions. Technological developments across the broad suite of low-carbon energy solutions are advancing rapidly, with ongoing innovations in renewable electricity generation, industrial processes, and energy-saving technologies and services, including LED lighting, induction heating, electric vehicles, energy storage solutions, and mobility as a service, plus smart devices, controls, and more efficient and smart buildings. Combining renewable electricity with biotic and abiotic pathways to produce chemicals, fuels, and materials promises to deliver new solutions. Grid-interactive buildings and communities, integrating transportation infrastructure and vehicles, are likely to be significant components of any zero-carbon energy strategy. Low-carbon industrial manufacturing will also make strong contributions to a net-zero economy. While the technical prospects appear promising, variations in the state of infrastructure, jurisdictional and social equity, pollution, economic and socio-cultural constraints, energy resource availability, and supply chain dynamics found in different locations present a range of challenges and demand customized solutions. This paper provides a critical review and offers new insights into the technical, infrastructure, analytic, political, and economic challenges faced in translating the nation's ambitious net-zero-emissions goals into feasible and reliable implementation action plans. • This manuscript brings together multiple experts view on the State of technologies, System level solutions, economics and scaling, for the United States to achieve bold decarbonization goals by 2050. • Key insights are offered on power system decarbonization, the role of hydrogen, storage, transportation, integrated energy systems, and material utilization and circularity. • Technologies, particularly wind and solar, are increasingly cost-effective, yet challenges remain regarding integration, social and political economy issues, and energy and environmental justice. • While the technical and economic factors are increasingly favorable, the US faces a number of non-technical challenges to rapidly scale clean energy technologies in order to achieve its ambitious goals. [ABSTRACT FROM AUTHOR]

The United States is affected by an average of almost seven severe weather events a year, often resulting in billions of dollars in physical and economic damages, a subset of which are related to grid outages. There is a need for power and energy system stakeholders to better understand and implement the strategies that help reduce net-economic and societal consequences associated with grid outages by improving the resilience of their systems. In addition, there are incentives to reduce emissions and meet climate goals, several pathways of which include resilient technologies. Including resilience constraints and metrics in energy system planning models may help inform the design of more resilient systems that are also more renewable and sustainable. This paper reviews qualitative definitions of resilience, quantitative approaches to resilience, recent examples of the inclusion of resilience in energy system models with respect to acute climatological threats, and the gaps in fully articulating resilience in current modeling tools. We then outline steps to effectively improve resilience considerations against such threats into energy sector modeling tools. Based on the findings, the authors propose a novel framework for energy system resilience assessment and future areas of research to bridge the current modeling gaps. • To date, resilience concerns have been lacking in energy systems optimization models. • Research is needed to better understand how renewables can contribute to resilience. • Resilience concerns should include uncertainty and translate to economic costs. • Future modeling efforts of co-optimizing renewable and resilience goals should be applied to common and validated models. [ABSTRACT FROM AUTHOR]

This paper presents a framework for pricing the climate resilience of an energy infrastructure project through assessing the value of its required debt and equity investments. Integrating climate scenarios into an asset valuation model provides useful and specific insights for risk management, but there is a lack of academic and market tools that effectively address this need. The critical barrier is that climate-related risks (physical and transition) are typically indirect variables in the cash flow calculation, and they should be computed based on the direct variables such as revenue, capital expenditures, operating expenses, and financing costs. The implementation of this framework shows how to delineate climate-related risks that are asset-specific and transforms them into financial risks. Using cash flow simulation and scenario analysis, it estimates an energy infrastructure asset's probability of default due to climate-related risks and the size and timing of the losses for any given default. To demonstrate the framework's application, we simulate the price climate-related risks of a utility-scale electricity generation facility powered by natural gas. • The analysis focuses on climate-related financial risk assessment of infrastructure assets. • An asset-level and forward-looking climate risk assessment framework is developed. • It tests single or combined climate risk scenarios on conventional financial metrics. • A case study on a natural gas power plant in the United States is demonstrated. [ABSTRACT FROM AUTHOR]

Utilization of food waste (FW) and food processing waste streams in waste-to-energy technologies has increased over the years in United States (US). This review paper compiled information from published literature and open data sources to obtain a holistic view of the current state of FW availability and its management using anaerobic digestion (AD). The review examined the usage of FW as a feedstock for AD by considering the feedstock composition and availability of FW in the US as well as challenges and opportunities with implementing FW in mono- and co-digestion. Also presented are global trends in FW digestion and the current status of FW co-digestion in the US. FW in the US was characterized with regard to volume and composition to show a need for waste management and an opportunity for valuable resource recovery. Challenges and opportunities of processing via AcoD were presented to review best practices for successful operations. Environmental standards, economic incentives, and governmental policies in the US and around the world regarding waste management and utilization were discussed to identify barriers and sources of opportunity for large-scale implementation of AcoD. A range of facilities throughout the US was examined for information regarding digestion type, feedstock(s), biogas production and utilization, and energy self-sufficiency to better understand the current status of FW digestion. Several US facilities were outlined as case studies that co-digest FW and produce and utilize biogas for various applications. Future strategies, perspectives, and roadmaps were discussed to elucidate the shaping of future FW management practices. • Recognizes a need for sustainable management of food loss and waste in the US. • Identifies anaerobic co-digestion as a valuable waste-to-energy technology. • Characterizes food waste as a co-digestion feedstock in the United States. • Discusses barriers and opportunities to implementing co-digestion in the US. • Presents examples of co-digestion increasing biogas yield and generating revenue. [ABSTRACT FROM AUTHOR]