Exploratory analysis of high-resolution power interruption data reveals spatial and temporal heterogeneity in electric grid reliability

Modern grid monitoring equipment enables utilities to collect detailed records of power interruptions. These data are aggregated to compute publicly reported metrics describing high-level characteristics of grid performance. The current work explores the depth of insights that can be gained from public data, and the implications of losing visibility into heterogeneity in grid performance through aggregation. We present an exploratory analysis examining three years of high-resolution power interruption data collected by archiving information posted in real-time on the public-facing website of a utility in the Western United States. We report on the size, frequency and duration of individual power interruptions, and on spatio-temporal variability in aggregate reliability metrics. Our results show that metrics of grid performance can vary spatially and temporally by orders of magnitude, revealing heterogeneity that is not evidenced in publicly reported metrics. We show that limited access to granular information presents a substantive barrier to conducting detailed policy analysis, and discuss how more widespread data access could help to answer questions that remain unanswered in the literature to date. Given open questions about whether grid performance is adequate to support societal needs, we recommend establishing pathways to make high-resolution power interruption data available to support policy research.Comment: Journal submission (in review), 22 pages, 8 figures, 1 tabl

Preliminary Estimates of Combined Heat and Power Greenhouse GasAbatement Potential for California in 2020

The objective of this scoping project is to help the California Energy Commission's (CEC) Public Interest Energy Research (PIER) Program determine where it should make investments in research to support combined heat and power (CHP) deployment. Specifically, this project will: {sm_bullet} Determine what impact CHP might have in reducing greenhouse gas (GHG) emissions, {sm_bullet} Determine which CHP strategies might encourage the most attractive early adoption, {sm_bullet} Identify the regulatory and technological barriers to the most attractive CHP strategies, and {sm_bullet} Make recommendations to the PIER program as to research that is needed to support the most attractive CHP strategies

An Examination of Temporal Trends in Electricity Reliability Based on Reports from U.S. Electric Utilities

Since the 1960s, the U.S. electric power system has experienced a major blackout about once every 10 years. Each has been a vivid reminder of the importance society places on the continuous availability of electricity and has led to calls for changes to enhance reliability. At the root of these calls are judgments about what reliability is worth and how much should be paid to ensure it. In principle, comprehensive information on the actual reliability of the electric power system and on how proposed changes would affect reliability ought to help inform these judgments. Yet, comprehensive, national-scale information on the reliability of the U.S. electric power system is lacking. This report helps to address this information gap by assessing trends in U.S. electricity reliability based on information reported by electric utilities on power interruptions experienced by their customers. Our research augments prior investigations, which focused only on power interruptions originating in the bulk power system, by considering interruptions originating both from the bulk power system and from within local distribution systems. Our research also accounts for differences among utility reliability reporting practices by employing statistical techniques that remove the influence of these differences on the trends that we identify. The research analyzes up to 10 years of electricity reliability information collected from 155 U.S. electric utilities, which together account for roughly 50% of total U.S. electricity sales. The questions analyzed include: 1. Are there trends in reported electricity reliability over time? 2. How are trends in reported electricity reliability affected by the installation or upgrade of an automated outage management system? 3. How are trends in reported electricity reliability affected by the use of IEEE Standard 1366-2003

Use of Frequency Response Metrics to Assess the Planning and Operating Requirements for Reliable Integration of Variable Renewable Generation

An interconnected electric power system is a complex system that must be operated within a safe frequency range in order to reliably maintain the instantaneous balance between generation and load. This is accomplished by ensuring that adequate resources are available to respond to expected and unexpected imbalances and restoring frequency to its scheduled value in order to ensure uninterrupted electric service to customers. Electrical systems must be flexible enough to reliably operate under a variety of"change" scenarios. System planners and operators must understand how other parts of the system change in response to the initial change, and need tools to manage such changes to ensure reliable operation within the scheduled frequency range. This report presents a systematic approach to identifying metrics that are useful for operating and planning a reliable system with increased amounts of variable renewable generation which builds on existing industry practices for frequency control after unexpected loss of a large amount of generation. The report introduces a set of metrics or tools for measuring the adequacy of frequency response within an interconnection. Based on the concept of the frequency nadir, these metrics take advantage of new information gathering and processing capabilities that system operators are developing for wide-area situational awareness. Primary frequency response is the leading metric that will be used by this report to assess the adequacy of primary frequency control reserves necessary to ensure reliable operation. It measures what is needed to arrest frequency decline (i.e., to establish frequency nadir) at a frequency higher than the highest set point for under-frequency load shedding within an interconnection. These metrics can be used to guide the reliable operation of an interconnection under changing circumstances

Cost of Power Interruptions to Electricity Consumers in the United States (U.S.)

The massive electric power blackout in the northeastern U.S. and Canada on August 14-15, 2003 catalyzed discussions about modernizing the U.S. electricity grid. Industry sources suggested that investments of $50 to$100 billion would be needed. This work seeks to better understand an important piece of information that has been missing from these discussions: What do power interruptions and fluctuations in power quality (power-quality events) cost electricity consumers? We developed a bottom-up approach for assessing the cost to U.S. electricity consumers of power interruptions and power-quality events (referred to collectively as "reliability events"). The approach can be used to help assess the potential benefits of investments in improving the reliability of the grid. We developed a new estimate based on publicly available information, and assessed how uncertainties in these data affect this estimate using sensitivity analysis

Cost of Power Interruptions to Electricity Consumers in the United States (U.S.)

The massive electric power blackout in the northeastern U.S. and Canada on August 14-15, 2003 catalyzed discussions about modernizing the U.S. electricity grid. Industry sources suggested that investments of $50 to$100 billion would be needed. This work seeks to better understand an important piece of information that has been missing from these discussions: What do power interruptions and fluctuations in power quality (power-quality events) cost electricity consumers? We developed a bottom-up approach for assessing the cost to U.S. electricity consumers of power interruptions and power-quality events (referred to collectively as "reliability events"). The approach can be used to help assess the potential benefits of investments in improving the reliability of the grid. We developed a new estimate based on publicly available information, and assessed how uncertainties in these data affect this estimate using sensitivity analysis

Understanding the cost of power interruptions to U.S. electricity consumers

The massive electric power blackout in the northeastern United States and Canada on August 14-15, 2003 resulted in the U.S. electricity system being called ''antiquated'' and catalyzed discussions about modernizing the grid. Industry sources suggested that investments of $50 to$100 billion would be needed. This report seeks to quantify an important piece of information that has been missing from these discussions: how much do power interruptions and fluctuations in power quality (power-quality events) cost U.S. electricity consumers? Accurately estimating this cost will help assess the potential benefits of investments in improving the reliability of the grid. We develop a comprehensive end-use framework for assessing the cost to U.S. electricity consumers of power interruptions and power-quality events (referred to collectively as ''reliability events''). The framework expresses these costs as a function of: (1) Number of customers by type in a region; (2) Frequency and type of reliability events experienced annually (including both power interruptions and power-quality events) by these customers; (3) Cost of reliability events; and (4) Vulnerability of customers to these events. The framework is designed so that its cost estimate can be improved as additional data become available. Using our framework, we estimate that the national cost of power interruptions is about $80 billion annually, based on the best information available in the public domain. However, there are large gaps in and significant uncertainties about the information currently available. Notably, we were not able to develop an estimate of power-quality events. Sensitivity analysis of some of these uncertainties suggests that the total annual cost could range from less than$30 billion to more than $130 billion. Because of this large range and the enormous cost of the decisions that may be based on this estimate, we encourage policy makers, regulators, and industry to jointly under take the comparatively modest-cost improvements needed in the information used to estimate the cost of reliability events. Specific areas for improvement include: coordinated, nationwide collection of updated information on the cost of reliability events; consistent definition and recording of the duration and frequency of reliability events, including power-quality events; and improved information on the costs of and efforts by consumers to reduce their vulnerability to reliability events