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Title: Utility Solar Generation Valuation Methods

Technical Report ·
DOI:https://doi.org/10.2172/1016166· OSTI ID:1016166

Tucson Electric Power (TEP) developed, tested and verified the results of a new and appropriate method for accurately evaluating the capacity credit of time variant solar generating sources and reviewed new methods to appropriately and fairly evaluate the value of solar generation to electric utilities. The project also reviewed general integrated approaches for adequately compensating owners of solar generation for their benefits to utilities. However, given the limited funding support and time duration of this project combined with the significant differences between utilities regarding rate structures, solar resource availability and coincidence of solar generation with peak load periods, it is well beyond the scope of this project to develop specific rate, rebate, and interconnection approaches to capture utility benefits for all possible utilities. The project developed computer software based evaluation method models to compare solar generation production data measured in very short term time increments called Sample Intervals over a typical utility Dispatch Cycle during an Evaluation Period against utility system load data. Ten second resolution generation production data from the SGSSS and actual one minute resolution TEP system load data for 2006 and 2007, along with data from the Pennington Street Garage 60 kW DC capacity solar unit installed in downtown Tucson will be applied to the model for testing and verification of the evaluation method. Data was provided by other utilities, but critical time periods of data were missing making results derived from that data inaccurate. The algorithms are based on previous analysis and review of specific 2005 and 2006 SGSSS production data. The model was built, tested and verified by in house TEP personnel. For this phase of the project, TEP communicated with, shared solar production data with and collaborated on the development of solar generation valuation tools with other utilities, including Arizona Public Service, Salt River Project, Xcel and Nevada Power Company as well as the Arizona electric cooperatives. In the second phase of the project, three years of 10 second power output data of the SGSSS was used to evaluate the effectiveness of frequency domain analysis, normal statistical distribution analysis and finally maximum/minimum differential output analysis to test the applicability of these mathematic methods in accurately modeling the output variations produced by clouds passing over the SGSSS array.

Research Organization:
Tucson Electric Power
Sponsoring Organization:
USDOE EERE Office of Solar Energy Technology (EE-2A)
DOE Contract Number:
FC36-07GO17035
OSTI ID:
1016166
Report Number(s):
DOE FC36-07GO17035-1; TRN: US201112%%389
Country of Publication:
United States
Language:
English