Daniel S. Shugar

Photovoltaics in the utility distribution system: The evaluation of system and distributed benefits

Results of work undertaken at the Pacific Gas and Electric Company to quantify the potential benefits of distributed grid-connected photovoltaic generation are presented. Methodologies and evaluations used to examine potential benefits of distributed generation for a test case are described. Results indicate there can be significant distributed benefits in carefully chosen transmission and distribution systems. It is concluded that these benefits could enable PV generation to be a potentially cost-effective alternative for utility planning. and thereby stimulate utility demand for PV systems. Specifically, it is demonstrated that PV power plants can relieve thermal overloads in selected utility distribution systems. Other benefits of strategically located PV systems are electrical loss savings, voltage support, and higher reliability.<<ETX>>

Commercialization of a value-engineered photovoltaic tracking system

Our paper summarizes research and development results to design and commercialize a value-engineered photovoltaic (PV) array tracking system. The PV system, called PolarTracker/sup TM/, was empirically demonstrated at the Solar Test and Research Facility (STAR) of Arizona Public Service Company (APS) by PowerLight corporation and New World Power. Performance data is presented. Value-engineering the PolarTracker/sup TM/ has accelerated the cost-effective implementation of PV in targeted grid-support applications, through reduction in production energy cost and increase in on-peak availability.

Optimizing roof-integrated photovoltaics: a case study of the PowerGuard roofing tile

This paper describes the development and implementation of a building-integrated photovoltaic (PV) roofing tile system that provides grid-connected electric power to buildings. The PV roofing tile system, together with waterproof membrane, insulation, and electrical interconnection, is called PowerGuard. PowerGuard is one of the first PV roofing systems for flat and moderately-sloped commercial buildings that replaces conventional roof materials without requiring membrane penetrations and mechanical fastening to building structures. When evaluated as a PV system, the building integration reduces the cost of a PowerGuard system by 14% to 26% rather than incurring a structural mounting cost of 18% to 22% to conventionally fasten the system. Data are reported from a 3.0 kW PowerGuard prototype operating in Folsom, California, USA. The PowerLight Corporation supplied the system using large-area amorphous silicon modules manufactured by Advanced Photovoltaic Systems, Inc. Performance data indicates the system is exceeding contractual requirements. Sensitivity analysis, based upon performance, installed costs, and supplier data, indicates: (1) a marginal economic advantage to tilting the PV array; (2) a marginal economic impact of increased PV efficiency; and (3) economies-of-scale which make PowerGuard systems economical today for commercial customers in sunny areas who pay high electricity rates.