Large-scale penetration of photovoltaics: impacts distribution systems and ancillary services

This talk will cover two works in progress that are based on a unique data set comprising 1 minute resolution production from a large number of residential photovoltaic systems. The first part of the talk will discuss recent efforts to use these data to determine how much generating capacity should be committed to deliver load following and frequency regulation to balance variability in photovoltaic production. At the center of the effort is a hidden Markov modeling framework that captures variability in weather regime (for example sunny, partly sunny, partly cloudy, cloudy) as well as geographic autocorrelation in output between sites. The second part of the talk focuses on understanding how placing photovoltaic system in distribution systems impacts including transformer aging, voltage regulator operations, substation transformer bank capacity requirements and resistive losses. We examine scenarios where total distributed PV capacity ranges from 15 to 100 percent of feeder peak demand. For the regions and periods we study, we find that even at 100 percent penetration there is relatively little impact on all the metrics we study, with the exception of resistive losses and substation bank capacity requirements.
Duncan Callaway is an Assistant Professor of Energy and Resources at the University of California, Berkeley and a faculty scientist at Lawrence Berkeley National Laboratory. Prior to joining the University of California, he was first a National Science Foundation (NSF) Postdoctoral Fellow at the Department of Environmental Science and Policy, University of California, Davis, subsequently worked as a Senior Engineer at Davis Energy Group, Davis, CA, and PowerLight Corporation, Berkeley CA, and was most recently a Research Scientist in the School of Natural Resources and Environment at the University of Michigan, Ann Arbor. His current research interests are in the areas of (i) modeling and control of aggregated electricity loads and storage devices, (ii) spatially distributed energy resources, (iii) environmental impact assessment of energy technologies, and (iv) using information technology to improve building energy efficiency.