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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 793 records · Page 44
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Los Alamos County Battery Energy Storage System Use Review

The purpose of this study is to identify potential alternative uses for the LAC-owned BESS. One critical fact that must be considered in evaluating any profitable use of the BESS is the standby cost associated with keeping the NaS battery on-line, as it must be kept at 300 degrees Celsius at all times, regardless of whether it is being used or not. Standby for the NaS battery online requires approximately 80 MWh/month, costing approximately 28,000 dollars annually. Other relevant costs include a 22,000 dollar annual maintenance contract required for the NaS, and accounting for any losses due to inefficiencies during the operation of the battery. County operations personnel respond to all alarms and visit the BESS on a monthly basis to walk down the site. It estimated this cost approximately 10,000 dollars per year. The total cost of maintaining and keeping the NaS battery on-line for a year, then, is roughly 60,000 dollars.

25 ENERGY STORAGE↗
DOE OSTI2019

Puget Sound Energy Glacier Energy Storage System: An Assessment of Battery Technical Performance

This report investigates the technical performance of the Glacier BESS facility, consisting of one 2 MW, 4 MWh BESS, based on a number of baseline and use case tests. Baseline tests were intended to assess the general technical capability of the BESS (e.g., stored energy capacity, ramp rate performance, ability to track varying charge/discharge commands, direct current (DC) battery internal resistance). Use case tests were used to examine the performance of the BESS while engaged in specific economic services (e.g., arbitrage, power factor correction). The project measured and/or calculated parameters that are important for understanding BESS performance when subjected to actual field operation for achieving economic benefits, e.g., round trip efficiency (RTE) with and without rest, with and without auxiliary loads, auxiliary power consumption, signal command tracking performance, temperature variations, parasitic power loss during power electronics switching during rest, and state of charge (SOC) excursions. These baseline and use case parameters were analyzed using recorded test results. In addition, the results and lessons presented herein are also beneficial for any task or effort that needs technical assessment on similar and different types of BESS based on field deployment results, since the assessment methodology remains the same.

25 ENERGY STORAGE↗
DOE OSTI2016

Reducing I/O variability using dynamic I/O path characterization in petascale storage systems

In petascale systems with a million CPU cores, scalable and consistent I/O performance is becoming increasingly difficult to sustain mainly because of I/O variability. Furthermore, the I/O variability is caused by concurrently running processes/jobs competing for I/O or a RAID rebuild when a disk drive fails. We present a mechanism that stripes across a selected subset of I/O nodes with the lightest workload at runtime to achieve the highest I/O bandwidth available in the system. In this paper, we propose a probing mechanism to enable application-level dynamic file striping to mitigate I/O variability. We also implement the proposed mechanism in the high-level I/O library that enables memory-to-file data layout transformation and allows transparent file partitioning using subfiling. Subfiling is a technique that partitions data into a set of files of smaller size and manages file access to them, making data to be treated as a single, normal file to users. Here, we demonstrate that our bandwidth probing mechanism can successfully identify temporally slower I/O nodes without noticeable runtime overhead. Experimental results on NERSC’s systems also show that our approach isolates I/O variability effectively on shared systems and improves overall collective I/O performance with less variation.

97 MATHEMATICS AND COMPUTING↗