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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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At least 613 records · Page 34
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Multi-Stage and Multi-Timescale Robust Co-Optimization Planning for Reliable and Sustainable Power Systems. Final Report

In this project, Clarkson University, in collaboration with Southern Methodist University and University of Pittsburgh, conducted the research to model, design, and implement a sophisticated generation and transmission co-optimization planning decision tool, called Multi-stage and Multi-timescale robust Co-Optimization Planning (MMCOP). The MMCOP decision tool intends to facilitate generation and transmission co-optimization planning of emerging power systems, while mitigating risks and uncertainties in both short-term operation dynamics and long-term policy and technology changes. Long-term power system planning aims at optimizing asset utilization by investing in a proper mix of various generation technologies and transmission lines to supply the future load growth. In particular, the Clean Power Plan (CPP), which is designed to combat climate change and reduce carbon emissions by setting a national limit on carbon pollution from power plants, may dramatically change the landscape of the power industry by further promoting clean energy and phasing out emissions-intensive generation technologies. In addition, novel non-wire alternatives (e.g., demand response (DR), distributed generation (DG), energy efficiency (EE), and smart grid technologies) and the computational complexity for large-scale systems significantly complicate the system planning procedure even further. However, existing conventional planning approaches neglect short-term variability and uncertainty of renewable energy, hourly chronological operation details, and physical nonlinear characteristics of the alternating current transmission network. As a result, existing conventional planning approaches may not work properly, and power systems reliability could be in jeopardy. In observing the limitations of existing conventional planning approaches and addressing new challenges of emerging power systems, the main scope of this project to develop co-optimization planning models within a multi-stage and multi-timescale framework. In particular, random contingencies, key uncertainty factors, and AC power flows are included to derive expansion plans while considering both long-term reliability and short-term flexibility.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2019

Distributed energy management for community microgrids considering phase balancing and peak shaving

Here, a distributed energy management for community microgrids considering phase balancing and peak shaving is introduced. In each iteration, the house energy management system (HEMS) installed in each house minimises its electricity costs and the costs associated with the discomfort of customers due to deviations in indoor temperature from customers’ set points. At the community level, the microgrid central controller (MCC) schedules the distributed energy resources (DERs) and energy storage based on the received load profiles from customers and the forecast energy price at the point of common coupling. The MCC updates the energy price for each phase based on the amount of unbalanced power between generation and consumption. The updated energy price and unbalanced power for each phase are distributed to the HEMSs on corresponding phases. When the optimisation converges, the unbalanced power of each phase is close to zero. Meanwhile, the schedules of DERs, energy storage systems and the energy consumption of each house are determined by the MCC and HEMSs, separately. Specifically, the phase balancing and peak shaving are considered in the proposed distributed energy management model. The effectiveness of the proposed distributed energy management has been illustrated by case studies.

25 ENERGY STORAGE↗
DOE OSTI2016

SU-F-SPS-10: The Dosimetric Comparison of GammaKnife and Cyberknife Treatment Plans for Brain SRS Treatment

Purpose: Brain stereotactic radiosurgery (SRS) involves the use of precisely directed, single session radiation to create a desired radiobiologic response within the brain target with acceptable minimal effects on surrounding structures or tissues. In this study, the dosimetric comparison of GammaKnife perfection and Cyberknife M6 treatment plans were made. Methods: Treatment plannings were done for GammaKnife perfection unit using Gammaplan treatment planning system (TPS) on the CT scan of head and neck randophantom simulating the treatment of sterotactic treatments for one brain metastasis. The dose distribution were calculated using TMR 10 algorithm. The treatment planning for the same target were also done for Cyberknife M6 machine using Multiplan (TPS) with Monte Carlo algorithm. Using the same film batch, the net OD to dose calibration curve was obtained using both machine by delivering 0- 800 cGy. Films were scanned 48 hours after irradiation using an Epson 1000XL flatbed scanner. Dose distribution were measured using EBT3 film dosimeter. The measured and calculated doses were compared. Results: The dose distribution in the target and 2 cm beyond the target edge were calculated on TPSs and measured using EBT3 film. For cyberknife treatment plans, the gamma analysis passing rates between measured and calculated dose distributions were 99.2% and 96.7% for target and peripheral region of target respectively. For gammaknife treatment plans, the gamma analysis passing rates were 98.9% and 93.2% for target and peripheral region of target respectively. Conclusion: The study shows that dosimetrically comparable plans are achievable with Cyberknife and GammaKnife. Although TMR 10 algorithm predicts the target dose.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Benefit-Cost Analysis for Utility-Facing Grid Modernization Investments: Trends, Challenges, and Considerations

In recent years, many electric utilities have submitted grid modernization plans for review by state public utility commissions. A central objective of these plans is to demonstrate that grid modernization investments will provide net benefits to customers, be reasonable and be in the public interest. The plans typically include some form of benefit-cost analysis, but the assumptions, methodologies and frameworks vary considerably between utilities. This report: -Describes utility-facing technologies and projects for modernizing distribution systems, including interdependencies of grid components -Highlights benefit-cost considerations related to grid modernization -Summarizes recent trends in benefit-cost analysis for grid modernization based on a review of 21 plans by U.S. electric utilities -Discusses challenges state public utility commissions face in reviewing utility plans and provides options for addressing challenges

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2016

SU-F-P-21: Study of Dosimetry Accuracy of Small Passively Scattered Proton Beam Fields

Purpose: To study the accuracy of the dose distribution of very small irregular fields of passively scattered proton beams calculated by the analytical pencil beam model of the Eclipse treatment planning system (TPS). Methods: An irregular field with a narrow region (width < 1 cm) that was used for the treatment of a small volume adjacent to a previously treated area were chosen for this investigation. Point doses at different locations inside the field were measured with a small volume ion chamber (A26, Standard Imaging). 2-D dose distributions were measured using a 2-D ion chamber array (MatriXX, IBA). All the measurements were done in plastic water phantom. The measured dose distributions were compared with the verification plan dose calculated in a water like phantom for the patient treatment field without the use of the compensator. Results: Point doses measured with the ion chamber in the narrowest section of the field were found to differ as much as 10% from the Eclipse calculated dose at some of the points. The 2-D dose distribution measured with the MatriXX which was validated by comparison with limited film measurement, at the proximal 95%, center of the spread out Bragg Peak and distal 90% depths agreed reasonably well with the TPS calculated dose distribution with more than 92% of the pixels passing the 2% / 2 mm dose distance agreement. Conclusion: The dose calculated by the pencil beam model of the Eclipse TPS for narrow irregular fields may not be accurate within 5% at some locations of the field, especially at the points close to the field edge due to the limitation of the dose calculation model. Overall accuracy of the calculated 2-D dose distribution was found to be acceptable for the 2%/2 mm dose/distance agreement with the measurement.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Resilience Analytics for Interdependent Power and Water Distribution Systems

The occurrence of large-scale outages in power distribution systems (PDSs) caused, for instance, by extreme weather events has raised concerns on the cascading impact of the power outages on the resilience of other critical infrastructures, including water distribution systems (WDSs), whose healthy operation highly relies on the availability of power from PDSs. Here, this paper proposes an analytics model for quantifying the interdependence between the resilience of power and water distribution systems. The proposed model first performs spatio-temporal outage analysis on the PDS and WDS to determine the PDS power serving capability and the resulting cascading impact on the WDS water serving capability during the occurrence of disruptions. The resilience interdependence is then determined by a proposed set of six metrics calculated using the power and water serving capability profiles, which trace and quantify the cascading impacts of power outages in the operation of WDSs during the degradation and recovery stages. The proposed analytics model is implemented on the IEEE 33-bus power distribution system supplying power for pumping stations of a 15-node test WDS, considering multiple cases of water storage capacity, single and multiple outage scenarios, and availability of distributed generation. The numerical results demonstrate that the proposed metrics track the temporal and spatial interdependence between the resilience of power and water distribution systems, providing a mechanism to identify weak spots, and assess options to enhance the resilience of the critical water infrastructure.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2024

Explained: Fundamentals of Power Grid Reliability and Clean Electricity

Maintaining reliability of the bulk power system, which supplies and transmits electricity, is a critical priority for electric grid planners, operators, and regulators. As we move toward a cleaner electricity system with more technologies like wind, solar, and battery storage, the way in which we plan for and achieve reliability will change. This fact sheet provides additional technical background to the topics covered in three other reliability explainers on how we measure, enforce, and plan for reliable systems with more clean electricity.

POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2015

SU-E-T-547: Modeling Biological Response to Proton Irradiation and Evaluating Its Potential Clinical Consequences

Purpose: In addition to physical uncertainties, proton therapy may also be associated with biologic uncertainties. Currently a generic RBE value of 1.1 is used for treatment planning. In this work the effects of variable RBE, in comparison to a fixed RBE, were evaluated by calculating the effective dose for proton treatments. Methods: The repair misrepair fixation (RMF) model was used to calculate variable proton RBEs. The RBE weighted spread-out Bragg peak (SOBP) dose in water phantom was calculated using Monte Carlo simulation and compared to 1.1 weighted SOBP dose. A head and neck proton treatment was used to evaluate the potential effects, by comparing the head and neck treatment plan computed with a commercial treatment planning system that incorporates fixed RBE of 1.1 and a Monte Carlo treatment planning system that incorporates variable RBE. Results: RBE calculations along the depth of SOBP showed that the RBE at the entrance is approximately 1 and reaches 1.1 near the center of the SOBP. However, in distal regions the RBE rises to higher values (up to 3.5 depending on the cell type). Comparison of commercial treatment plans using a fixed RBE of 1.1 and Monte Carlo using variable RBE showed noticeable differences in the effective dose distributions. Conclusion: The comparison of the treatment planning with fixed and variable RBE shows that using commercial treatment planning systems that incorporate fixed RBE (1.1) could Result in overestimation of the effective dose to part of head and neck target volumes, while underestimating the effective dose to the normal tissue beyond the tumor. The accurate variable RBE as a function of proton beam energy in patient should be incorporated in treatment planning to improve the accuracy of effective dose calculation.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2021

Electromagnetic Transient (EMT) Simulation Algorithm for Evaluation of Photovoltaic (PV) Generation Systems

Use of inverter-based resources facilitating renewable energy resources such as photovoltaic (PV) generation is increasing rapidly with decreasing costs and reduced emissions associated. To accommodate such rapid growth of inverter-based resources like PV systems, electromagnetic transient (EMT) simulation models of both PV systems and grids are required to analyze the interaction of PVs in the grid (like the post-event analysis). In addition, the EMT simulation would help with the planning of future power grid with a large number of PVs as well as other inverter-based distributed generation systems. In this paper, the EMT simulation models of PV systems and grids are developed based on the differential algebraic equations (DAEs) representing their EMT dynamics. Furthermore, advanced simulation algorithms including numerical stiffness-based hybrid discretization, DAE clustering and aggregation, multi-order integration, and matrix splitting approaches are applied to accelerate the EMT simulation. The proposed algorithm was applied to 125 PV inverters within 52-bus medium-voltage (MV) distribution grid.

Choi, Jongchan↗
DOE OSTI2016

SU-G-201-17: Verification of Dose Distributions From High-Dose-Rate Brachytherapy Ir-192 Source Using a Multiple-Array-Diode-Detector (MapCheck2)

Purpose: To investigate quantitatively the accuracy of dose distributions for the Ir-192 high-dose-rate (HDR) brachytherapy source calculated by the Brachytherapy-Planning system (BPS) and measured using a multiple-array-diode-detector in a heterogeneous medium. Methods: A two-dimensional diode-array-detector system (MapCheck2) was scanned with a catheter and the CT-images were loaded into the Varian-Brachytherapy-Planning which uses TG-43-formalism for dose calculation. Treatment plans were calculated for different combinations of one dwell-position and varying irradiation times and different-dwell positions and fixed irradiation time with the source placed 12mm from the diode-array plane. The calculated dose distributions were compared to the measured doses with MapCheck2 delivered by an Ir-192-source from a Nucletron-Microselectron-V2-remote-after-loader. The linearity of MapCheck2 was tested for a range of dwell-times (2–600 seconds). The angular effect was tested with 30 seconds irradiation delivered to the central-diode and then moving the source away in increments of 10mm. Results: Large differences were found between calculated and measured dose distributions. These differences are mainly due to absence of heterogeneity in the dose calculation and diode-artifacts in the measurements. The dose differences between measured and calculated due to heterogeneity ranged from 5%–12% depending on the position of the source relative to the diodes in MapCheck2 and different heterogeneities in the beam path. The linearity test of the diode-detector showed 3.98%, 2.61%, and 2.27% over-response at short irradiation times of 2, 5, and 10 seconds, respectively, and within 2% for 20 to 600 seconds (p-value=0.05) which depends strongly on MapCheck2 noise. The angular dependency was more pronounced at acute angles ranging up to 34% at 5.7 degrees. Conclusion: Large deviations between measured and calculated dose distributions for HDR-brachytherapy with Ir-192 may be improved when considering medium heterogeneity and dose-artifact of the diodes. This study demonstrates that multiple-array-diode-detectors provide practical and accurate dosimeter to verify doses delivered from the brachytherapy Ir-192-source.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2020

The Evolving U.S. Distribution System: Technologies, Architectures, and Regulations for Realizing a Transactive Energy Marketplace

As pockets of the U.S. experience growing penetrations of distributed energy resources (DERs), the traditional practices underpinning distribution system regulation, operation, and management are evolving. The challenges and opportunities that DERs pose are driving stakeholders across the United States to reconsider regulatory goals, utility business models, ratemaking, and grid architectures. This report reviews the evolution of the U.S. distribution system from the advent of the utility-as-regulated-monopoly business model to the technological and regulatory shifts happening. The report concludes with a discussion of transactive energy systems and summarizes some of the leading RD&D happening in this field.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2021

Develop a weather-aware climate model to understand and predict extremes and associated power outages and renewable energy shortages with uncertainty-aware and physics-informed machine learning

Focal Area(s): The focus area is predictive modeling through the use of AI techniques and AI-derived model components with a particular emphasis on extreme weather in Atmospheric Science and power outages and shortages in Energy Science. Science Challenge: Predicting weather extremes (e.g., heavy precipitation, strong wind, and large hailstones), and weather-related power system outages and shortages can mitigate economic losses, save lives, support renewables integration, and improve power system resiliency. However, currently, the poor reliability and large uncertainty associated with the weather extreme prediction in the current climate models make the problem intractable. The key challenges are: (1) physical factors like green-house gases (GHGs), aerosols, and land use and land cover (LULC) can significantly impact extreme storms, but the understanding of these impacts is limited, particularly globally; (2) the convective permitting resolutions needed to model severe convective storms and their impacts are computationally prohibitive with global climate models (GCMs); (3) interactions between weather extremes and power system outages are complex and subject to great uncertainty. Current outage prediction models are short lead (~ 3 days), which do not allow for long-time planning of energy production and distribution. Moreover, we have limited capacity to predict weather events leading to sustained shortages in a renewable-energy-dominated power system. These challenges drive motivation for mechanistic understanding and reliable and efficient predictive modeling of extremes and their impacts from the sub-seasonal to long term projections.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Institutional Boilers - Guidance for Calculating Efficiency Credits Resulting from Implementation of Energy Conservation Measures

The purpose of this document is to provide guidance for developing a consistent approach to documenting efficiency credits generated from energy conservation measures in the Implementation Plan for boilers covered by the Boiler MACT rule (i.e., subpart DDDDD of CFR part 63). This document divides Boiler System conservation opportunities into four functional areas: 1) the boiler itself, 2) the condensate recovery system, 3) the distribution system, and 4) the end uses of the steam. This document provides technical information for documenting emissions credits proposed in the Implementation Plan for functional areas 2) though 4). This document does not include efficiency improvements related to the Boiler tune-ups.

Papar, Riyaz↗
DOE OSTI2012

National Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Institutional Boilers - Guidance for Calculating Emission Credits Resulting from Implementation of Energy Conservation Measures

The purpose of this document is to provide guidance for developing a consistent approach to documenting efficiency credits generated from energy conservation measures in the Implementation Plan for boilers covered by the Boiler MACT rule (i.e., subpart DDDDD of CFR part 63). This document divides Boiler System conservation opportunities into four functional areas: 1) the boiler itself, 2) the condensate recovery system, 3) the distribution system, and 4) the end uses of the steam. This document provides technical information for documenting emissions credits proposed in the Implementation Plan for functional areas 2) though 4). This document does not include efficiency improvements related to the Boiler tune-ups.

boiler↗
DOE OSTI2022

Analysis of Multi-Output Hybrid Energy Systems Interacting with the Grid: Application of Improved Price-Taker and Price-Maker Approaches to Nuclear-Hydrogen Systems

The growing recognition of the value of hydrogen as an energy intermediate in supporting future power systems with high shares of variable renewable energy has prompted many studies to quantify the economic potential of multi-output hybrid systems, which are one type of integrated energy systems (IES). Because of the complexity of modeling multiple sectors, these studies typically use simplified modeling approaches to capture the interactions between sectors. In this study, we explore the implications of alternative modeling approaches for nuclear-hydrogen IES focusing on a power system in the Midwest United States. We combine highly resolved capacity expansion and production cost modeling tools of the power system with a detailed hydrogen system optimization tool to determine the optimal electrolyzer and storage sizing and optimal operations of the nuclear-hydrogen hybrid resource across three future study years. We compare economic and operational outcomes across a spectrum of modeling approaches, including a non-hybridized base approach; a traditional price-taker approach that does not include the impact of hydrogen production on the electricity system; a power-system-focused price-maker approach that does not account for temporal hydrogen constraints; and two improved price-taker and price-maker approaches that each address the impact of revenue-optimal levels of electricity production on the resulting power system and temporal hydrogen constraints on the overall feasible solution. Results show how a traditional price-taker approach can overestimate the economic benefits of multi-output nuclear-hydrogen IES compared to our two improved approaches that estimate both hydrogen system constraints and power system interaction. We find that hydrogen output requirements and storage size limits are key drivers to overall operations and some economic outcomes. Under our assumed constant hydrogen output requirement, storage costs, test system, and modeling approaches, our results indicate that hybridization can provide a net benefit, but results are sensitive to the treatment of hydrogen revenues and electricity prices as impacted by the power system evolution.

capacity expansion modeling↗
DOE OSTI2022

Optimal Energy Storage System and Smart Switch Placement in Dynamic Microgrids With Applications to Marine Energy Integration

Here this paper studies a dynamic microgrid (DMG) planning problem that places energy storage systems (ESSs) and smart switches (SSWs) optimally in the system. We apply the proposed methodology to applications concerning marine renewable energy (MRE). MRE is an emerging clean energy resource with enormous capacity but volatile and intermittent energy output profiles. Innovative grid-integration technologies designed to enhance the reliability of an MRE-integrated system are needed. However, there are still limited studies in this regard. Existing works have shown the promising prospect of using a dynamic microgrid (DMG) operational concept to accommodate renewable resources in distribution systems, but they usually assume fixed ESS and SSW installations. To further improve the operational flexibility of DMGs, we propose a DMG planning methodology that optimally places ESSs and SSWs so that a DMG with MRE is warranted with proper resource adequacy and topological flexibility in both the contingency and normal operations. We use realistic case studies based on a real-world distribution network and the U.S. Department of Energy's MRE dataset to verify the value and validity of the proposed work.

25 ENERGY STORAGE↗