Factors Relevant to Utility Integration of Intermittent Renewable Technologies

Abstract

Preface Factors Relevant to Utility Integration of Intermittent RenewableTechnologies is a study and literature review looking at various factors relevant to the integration of intermittent renewable energy technologies into electric systems. The three topics covered in this report are interface factors, operability/stability factors, and planning factors that electric utilities have to address before large-scale integration of intermittent renewable energy technologies can take place. The purpose is to assess the state of knowledge of these factors and their relative significance today, and thus provide guidance to analysts in their evaluation of technologies and to researchers in their pursuit of tools and strategies to define and mitigate potential impacts.This report is one of a series of analyses being undertaken by the Analytic Studies Division of the National Renewable Energy Laboratory to provide insights into issues pertinent to renewable energy research and development activities. The Office of Utility Technologies of the Department of Energy funded this study.The authors are indebted to many people who reviewed the draft of this report and offered helpful comments. We especially want thank Joe Iannucci of Pacific Gas and Electric Company for his comments and valuable suggestions. Executive Summary ObjectiveThis study of the factors relevant to integrating intermittent renewable technologies into utility systems is one of a series of analyses being undertaken to provide insights into issues pertinent to renewable energy research and development activities. The purpose of this study is to assess the current state of knowledge of various factors that utilities must address in integrating intermittent renewable technologies, such as windor solar-based systems, into utility power-supply systems.Past studies indicated that utilities have concerns about the substantial differences between intermittent renewable technologies and conventional sources of utility power supply. These issues and concerns can impede the deployment of renewable technologies in utility systems if questions remain unanswered or technologies appear detrimental to standard utility operations. The goal of this study is to assess the relative significance of these concerns today and thus guide analysts in their evaluation of various technologies and researchers in their pursuit of tools and strategies to define or mitigate impacts.Integration studies from the late 1970s and early 1980s provide a starting point for assessing relevant issues, but these older studies have not been consolidated into a consistent data base nor updated to today's higher standards of analytic capability. Many recent studies have added to the knowledge base of renewable technology integration issues. In addition, significant changes have taken place in the utility marketplace regarding regulatory practices, energy and environmental policies, the resource selection process, and the development of non-utility generators. These changes have altered the type and lev...

Industrial symbiosis of very large-scale photovoltaic manufacturing

“…The problem of fluctuating cloud conditions can be solved simply by deploying solar PV over a larger area; if a network of PV installations is dispersed over 100 km 2 the tolerable penetration increases to 18.1%, and if the area is 1,000 km 2 the limit is 35.8% [26]. In a review of several studies, an upper penetration limit of PV generation of 16% is estimated for a system load set by the worst-case cloud pattern [27]. Combined, these factors have enormous potential economic return for any of the world's governments.…”

Exploring the impact on cost and electricity production of high penetration levels of intermittent electricity in OECD Europe and the USA, results for wind energy

“…Availability and quality are largely outside control of the system operator, which has technical and economic consequences for the power system at time scales varying from seconds and minutes to days and longer [27,28]. The focus of this study is mainly on the time-scale of days and longer, approximating more short-term aspects in aggregated system parameters (see Section 4).…”

“…For a system with up to 5-10% of its installed capacity in the form of wind turbines, most utilities accept 20-30% of the installed wind capacity as guaranteed. The remainder shows up in the form of cost-increasing back-up power that has to be installed additionally [11,13,27,30]. Part of these costs should be allocated to wind electricity production.…”

“…Large numbers of quick-start plants such as gas turbines and/or hydropower or storage plants with high load-following capability can absorb larger amounts of intermittent supply than typical base-load units such as large nuclear and coal-fired plants [11,27]. If large fluctuations occur, this cannot be dealt with using baseload plants.…”

“…With high penetration of intermittent sources, it needs to be higher and leads to more fuel use and emissions. A typical level of spinning reserve at system level is 1.5-3% of the peak load [27], depending amongst others on the size of the largest plant. Estimates of the spinning reserve required at high wind power penetration given in the literature range from about 10% to 85% of the installed wind capacity [12,14,30].…”