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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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This profile provides a snapshot of the energy landscape of Curacao, an autonomous member of the Kingdom of the Netherlands located off the coast of Venezuela. Curacao's residential utility rates are approximately $0.35 per kilowatt-hour (kWh). Rates are calculated on usage.
This profile provides a snapshot of the energy landscape of Bonaire, a special municipality of the Kingdom of the Netherlands located off the coast of Venezuela. Bonaire’s utility rates are approximately $0.22 per kilowatt-hour (kWh), plus fixed use monthly charges that are based upon connection capacity.
This profile provides a snapshot of the energy landscape of Antigua and Barbuda, an independent nation in the Leeward Islands in the eastern Caribbean Sea. Antigua and Barbuda's base residential utility rates are approximately $0.15 U.S. dollars (USD) per kilowatt-hour (kWh) plus a variable fuel charge.
In response to the potentially large and irregular demand from EVs, along with changing load profiles from buildings with on-site generation, utilities are evaluating multiple options for managing dynamic loads, including time-of-use pricing, demand charges, battery storage, and curtailment of variable generation. Buildings, as well as commercial, public, and workplace EV charging operations, can use a combination of electrochemical battery storage and thermal energy storage coupled with on-site generation to manage energy costs as well as provide resiliency and reliability for EV charging and building energy loads. We are completing a behind the meter storage analysis that focuses on determining the optimal system designs and energy flows for thermal and electrochemical behind the meter storage with on-site solar photovoltaic (PV) generation enabling electric vehicle charging in various climates, building types, and utility rate structures. In completing this analysis, we have developed a tool that combines existing battery models via the System Advisor Model (SAM) and building modeling software via EnergyPlus into a single interface. This tool allows us to simulate a building with a detailed battery model to properly size the battery, thermal energy storage, and solar PV systems to maximize profit for the system owner. This also allows us to assess how the battery degrades under various supervisory control dispatch algorithms to control charging/discharging; we can also see how thermal energy storage is created and used to complement the battery to reduce thermal loads in the building. With this project, we can analyze new batteries that are designed specifically for energy storage, rather than designed to be extremely energy dense for electric vehicle applications, using battery lifetime models from other national labs and the existing SAM battery model, which has detailed lifetime and degradation parameters. We can also assess novel thermal storage technologies by integrating them into the whole building energy simulation program EnergyPlus. Because the model calls both SAM and EnergyPlus, required inputs need to be compatible for both models. These inputs include, on a high-level, the following: weather files, building and electric vehicle load profiles, electricity rate tariff information, and system cost information for the stationary battery, solar PV, and thermal storage system. The various buildings we are studying for this analysis are retail big-box grocery store, commercial office building, fleet vehicle depot and operations facility, multi-family residential, and electric vehicle charging station. For these different applications, the battery and thermal storage will be dispatched differently, and the various technologies are sized differently to optimize cost.
As the capital cost of battery energy storage systems (BESS) declines, opportunities for commercial buildings to achieve net savings through peak demand management and energy arbitrage are emerging. National Renewable Energy Laboratory researchers modeled energy storage project economics - with and without accompanying solar photovoltaic systems - using local utility rates, ASHRAE climate zones, and solar intensity data to identify regions where these systems deliver life cycle savings now and in future cost scenarios.
Faults in commercial buildings can cause energy waste and other performance problems such as reduced occupant comfort, reduced equipment longevity, and increased noise. However, it is currently unknown how commonly faults occur in different equipment types. A method has been developed to estimate the prevalence of faults in air handling units, air terminal units, and rooftop units. This method includes two types of data. The first is data from several automated fault detection and diagnostics (AFDD) software technologies. This type of data provides a large sample that represents a wide range of building types, geographical locations, and equipment types. It includes fault diagnoses from thousands of buildings around the United States, as well as anonymized metadata describing the building and equipment characteristics. The number of fault records is in the order of 107. However, despite the size and richness of the data sample, this data contains some degree of inaccuracy, i.e., false positive and false negative findings. Therefore, the study includes a second type of data, coming from manual inspection of buildings that have had the same AFDD methods applied to them (from the commercial AFDD offerings). Since the field tests are conducted in buildings with AFDD-generated fault prevalence data, they can be combined with the larger sample size to provide insight into the potential biases or lower sensitivity of the AFDD data. Once a library of fault prevalence data is built, it will be studied to provide further insight into the drivers of fault prevalence, for example, whether prevalence is correlated with building type, geographical location (which is tied to climate and to utility rates), building size, etc. This paper describes the methods developed for this study and illustrates them with preliminary data. It discusses some of the challenges of harmonizing disparate outputs from multiple AFDD vendors, application of a unifying fault taxonomy, and fault prevalence metrics.
This poster provides summary cost details for a technoeconomic analysis of CO2 capture from flue gas generated by cement plants, conducted by U.S. Department of Energy National Energy Technology Laboratory and presented at the 2022 Carbon Management Project Review Meeting held in Pittsburgh, PA (August 15-19, 2022). A range of modern cement plant configurations was considered, along with different fuel types (coal, coke, and natural gas) and two levels of CO2 capture (95% and 99%). The sensitivity of capture cost to a range of modeling assumptions (such as fuel price, financing assumptions, utilization rate, and plant size) was also conducted, to show possible cost ranges that could be expected for decarbonization of typical cement plants in the U.S.
This webinar describes linkages between NREL's dGen, SAM, and REopt tools that were developed as a part of the RiDER project, including specifying utility rates in the SAM GUI and using them in dGen adoption analysis, and using REopt to determine optimal system sizes for dGen agents.
Combining battery energy storage with distributed wind energy systems can increase production, ability to meet local electricity demands, interconnection capacity, and potential sales of surplus energy back to the grid, while reducing demand charges and the overall levelized cost of energy (LCOE). Energy storage options for distributed wind energy systems can vary widely in terms of power level and energy storage capacity, and their potential benefits depend on factors including wind resource, turbine design, connection requirements, use patterns, utility rates, and regulations. Windurance received a 2022 Competitiveness Improvement Project (CIP) funding award to add battery energy storage capabilities to the company's bidirectional DC converter. The energy storage component will complete a comprehensive portfolio of power conversion and control electronics that can be seamlessly integrated with distributed wind systems. The company received earlier CIP awards to fund prototype design and construction of wind turbine pitch actuators, inverters, and controllers.
In this short technical report, we explore the range of levelized costs of dispensed hydrogen (H2) from hydrogen refueling (or fueling) stations (HRS) for H2 heavy-duty fuel cell electric vehicles (FCEVs) that are feasible in the 2030 timeframe. We explore different scenarios by varying hydrogen delivery distances, HRS sizes, HRS utilization rates, and economies of scale in the Hydrogen Delivery Scenario Analysis Model (HDSAM). Thus, we observe how the contribution to the levelized cost of each supply chain component changes.
This talk will focus on recent and planned modeling improvements to the NREL System Advisor ModelTM (SAM), with recently released features including PV hourly clipping correction, expanded geographic scope of SAM's NSRDB interface to Europe and Africa, and additional options for hybrids. Upcoming improvements include a case comparison feature, improved visualizations, and extensions of PVWatts for battery modeling and utility rate calculations.
Water heating accounts for about 18% of a typical US home’s energy use. Modern water heaters have enabled control options through APIs, offering customers the opportunity to reduce their energy cost and peak demand by dynamically adjusting settings. A water heater’s capacity to store energy using its storage tank makes it an asset for peak demand reduction and energy cost savings. For this reason, a mixed-integer linear programming model is proposed to minimize the energy cost of a high-performance water heater while also reducing the peak demand of the residential household under a time-of-use utility rate by dynamically changing the water heater’s running mode. Specifically, a multi-objective optimization model is formulated to determine the mode settings of the water heater considering hot water use, time-of-use rate, and peak demand limit of the residential household. The mode settings are associated with different dead bands of water temperature for triggering on/off action of the heat pump and heating element. A 66-gal hybrid electric high performance water heater was used for numerical simulation and practical experiments. The simulation results were well aligned with measurements of practical experiments, validating the soundness of the thermodynamic model. In addition, reductions of energy cost, enabling affordability, and reducing peak demand are demonstrated. The research team also developed a software framework with dashboards to automatically and continuously monitor and manage devices.
Carbon utilization is a crucially important performance characteristic of CO 2 electrolyzers; however, applications of simple and accurate descriptive models to experimental data on this topic are currently lacking. Here, we apply a simple analytical reactor model to parameterize single-pass conversion as a function of feed-gas flow rate and show that it captures a wide body of experimental data in the literature exceptionally well. In doing so, we demonstrate that this simple conceptual approach can characterize progress and capture recent innovations in reactor design. To validate the extracted parameters, we employ a well-established comprehensive model to confirm that the results agree with physical expectations. Lastly, we explore the implications of the descriptive model by examining the inherent trade-off between single-pass conversion efficiency and reactor productivity. Understanding such trade-offs is crucially important for advancing this electrolyzer technology toward commercial applications.
Four electrode impedance plethysmographic system for measuring left ventricular output
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This report compares the cost of different pathways for producing hydrogen in California. In addition to capturing the current cost of electrolyzers and other equipment, the pathways apply current retail electricity tariff options offered by utilities Southern California Edison (SCE), Pacific Gas & Electric Company (PG&E), and San Diego Gas & Electric Company (SDG&E). The analysis also tests the cost of combining hydrogen production with utility-scale wind or solar generation in California. Scenarios examine current costs as well as projections for 2030. The cost benchmark - a relatively low electrolytic hydrogen production cost - is based on the wholesale price of electricity used by a theoretical hydrogen production plant connected directly to the California Independent System Operator (CAISO) transmission system. California law currently prohibits this approach in CAISO, but it is permissible in other organized wholesale electricity markets. The cost for producing hydrogen under 2019 conditions in this theoretical case was approximately $3/kg. Different scenarios are used to examine current costs, e.g., 2019, as well as projections for 2030.
The effect of including triose phosphate utilization (TPU) on parameterization of the Farquhar, von Caemmerer, Berry model of photosynthetic gas exchange measurements is explored. Better fits to data are found even though TPU rarely limits photosynthesis under physiological conditions.
Device utilizing RC rate generators for continuous slow speed measurement