Five years of operating experience at a large, utility‐scale photovoltaic generating plant

Abstract

Tucson Electric Power Company (TEP), headquartered in Tucson, AZ, currently has nearly 5Á0 MWdc of utility-scale grid-connected photovoltaic (PV) systems installed in its service territory. These systems have been installed through a multiyear, pay-as-you-go development of renewable energy, with kWhac energy production as a key program measurement. This PV capacity includes a total of 26 crystalline silicon collector systems, each rated at 135 kWdc for a total of 3Á51 MWdc, that have been installed at the Springerville, AZ generating plant by TEP making this one of the largest PV plants in the world. This facility started operations in 2001 and recently passed the 5-year milestone of continuous operations. These systems were installed in a standardized, cookie-cutter approach whereby each uses the same array field design, mounting hardware, electrical interconnection, and inverter unit. This approach has allowed TEP to achieve a total installed system cost of $5Á40/Wdc and a TEP-calculated levelized energy cost of $0Á062/kWhac for PV electrical generation. This paper presents an assessment of operating experience including performance, costs, maintenance, and plant operation over this 5-year period making this one of the most detailed and complete databases of utility-scale PV systems available to the US DOE Program.

Design for reliability in power electronics in renewable energy systems – status and future

“…Among various surveys, the recent results studied in [6]- [7] are shown here as they are based on long-term collected data from a wide range of systems, which represent the typical cases that could be accessed in public domain. Field experiences of wind turbine systems studied in [6] (the full list of the name of the assemblies could be found in [6]).…”

“…In [7], the field data during 2001 -2006 in a large utilityscale PV generation plant composed of 11,700 identical PV modules and 26 identical inverters (each rated at 135 kW) have been analyzed. As shown in Fig.2, the PV inverters are responsible for 37% of the unscheduled maintenance and 59% of the associated cost.…”

“…Field experiences of a 3.5 MW PV plant [7]: (a) unscheduled maintenance events (b) unscheduled maintenance costs.…”

Evaluation and Design Tools for the Reliability of Wind Power Converter System

“…[1]- [3]. Power electronics tend to be fragile and have become a "bottleneck" of the whole wind turbine system, with respect to reliability [4]- [7]. This problem will significantly increase the cost of energy not only due to the increase in maintenance and repairs, but also because of the reduced energy delivered to the customers.…”

“…Today, most of the lifetime information of power semiconductors have to be collected by a statistics of failed products [5]- [7], and experience-based handbooks are written as a guide to determine the lifetime of different devices and designs. Not surprisingly, this approach has been proven to be untrusted and inaccurate as they are too general and application-independent.…”