The value of distributed generation: The PVUSA grid-support project serving Kerman Substation. Interim report, April 1994

A common practice of electric utilities experiencing transmission and distribution (T and D) system overloads is to expand the substation, add lines, or upgrade equipment, all of which are capital intensive options. In 1988, it was hypothesized that strategically sited photovoltaics (PV) could benefit parts of T and D systems near or at overloaded conditions. An evaluation methodology was developed and applied to a test case (Kerman Substation near Fresno, California). Analytical results suggested that the value of PV to the T and D system could substantially exceed its energy and generation capacity value. The importance of this finding indicated the need for empirical validation. This led to the construction of a 0.5 MW PV demonstration plant by Pacific Gas and Electric Company (PG and E) at Kerman, California as part of the PVUSA (PV for Utility Scale Applications) project. PVUSA is a national public-private partnership that is assessing and demonstrating the viability of utility-scale photovoltaic electric generation systems. The Kerman PV plant, commissioned for commercial operation in June, 1993, is reported to be the first grid-support PV demonstration plant in the world. This Interim Report focuses on validating the technical aspects of grid-support PV. It provides interim validation results for four of the eight identified value components that stack up to make the ``value bar``, and compares them to 1992 Case Study estimates. Results are based on improved technical evaluation methodologies, measured plant performance under a variety of conditions, and long-term plant performance estimated using a validated computer simulation program. This report is not intended to be exhaustive in scope. It does, however, provide a thorough progress update of the validation project. Complete documentation of test procedures, data, and evaluation methods will be presented in the Final Report