Distributed Renewable Energy Operating Impacts and Valuation Study

Section 1
Table 1-6
Energy Consumption for Selected APS Tariffs
Tariff
Demand During Peak Month (kW)
Annual Consumption
(kWh) Maximum Minimum
Residential E12 8,676 2.6 0.7
Residential ET-1 17,546 5.6 1.6
Commercial E32 Extra Small 26,103 7.2 2.2
Commercial E32 Small 189,058 43.3 17.5
Commercial E32 Medium 928,847 193.7 87.1
Commercial E32 Large 3,379,799 597.8 319.5
1.4 Study Description
There are 12 renewable technologies addressed in the Arizona Renewable Energy Standards and
APS has implemented incentive programs for all of them. While each will help APS achieve its
required goals for renewable energy, APS specifically limited this Study to three distributed solar
technologies that can be broadly deployed across its electrical system. The Study looked at the
financial, technical, policy and business case issues surrounding a significant successful
penetration of solar DE into residential and commercial applications. The Study focused on
solar PV in commercial and residential applications, solar hot water in the residential sector only,
and solar daylighting for commercial customers. The Study uses standard utility-industry
methodologies to analyze the impacts of solar DE resources on three key dimensions of utility
operations: distribution systems, transmission systems, and overall system planning.
This Study sought to develop common understanding among internal and external stakeholders
through a process of education and stakeholder involvement, all intended to help APS achieve its
intended goal for solar penetration. The Study design used a building block approach and was
organized into five distinct yet interrelated tasks. Each task formed the basis for the succeeding
tasks, and afforded critical internal and external stakeholder input. The task structure continued
throughout the study effort and is reflected in the organization of this Report.
Task 1 focused on characterizing the specific solar DE technologies addressed in this Study, in
terms of the current technical attributes and future potential improvements. The evaluation was
tailored to the specific conditions for use in Arizona, and then further narrowed to the APS
service territory and major customer locations in Phoenix and Yuma. Task 1 also focused on
modeling the deployment of these solar technologies across the APS system, and understanding
customer electrical usage across different customer classes.
Tasks 2, 3 and 4 provided a technical assessment of how these specific solar DE technologies
could provide value to APS in terms of distribution, transmission and power supply planning.
Task 2 utilized the results from the solar characterization to study the distribution system
benefits, which were used as a foundation for Task 3, where the Study examined the
transmission system as a whole. In Task 4, these results were reviewed on a consolidated system
basis to understand potential impacts and opportunities on energy and capacity planning.
1-12 R. W. Beck, Inc. Arizona Public Service