the customer load and solar production. APS
has added a set of real-time data acquisition
systems and weather stations on both the distribution system and the solar energy systems
to monitor the virtual power plant and collect
high-level study data.
the five-year project will
serve as a field verification
of high-penetration levels of
Pv into the distribution grid.
38 May 2012 SOLAR TODAY solartoday.org
the community Power
Project Business model
To achieve high penetration in
the selected distribution area, APS
needed a business model that made
it palpable to the homeowner and
economically responsible for the
utility. In Arizona, the choice to go
solar is largely an economic decision. The model had to address the
upfront costs to customers entering the solar market.
APS wants to learn whether
utility-owned DE assets are a sustainable line of business and if so,
what the best ways are to integrate
them into the company’s generation portfolio and grid-manage-ment operations.
Working closely with solar
installers and its regulator, the
Arizona Corporation Commission,
APS developed a model that put
the cost burden on the utility. APS
owns, operates and receives the
energy from the solar panels, essentially creating a mini power plant on
eligible customers’ rooftops. APS
contracts with local solar installers
to design, implement and maintain the systems at no cost to the
homeowner. The homeowner grants a rooftop
easement to APS and in return receives the
Community Power rate, a fixed rate for 20
years. All the systems are interconnected on
the utility side of the meter.
APS announced the Community Power
Project at Northern Arizona University on
May 11, 2009, and began taking customer
applications online in July 2010. Community
support for the project has been overwhelming. From a service area of just over 2,200
homes, more than 300 residential applications
were received. APS has completed the residential installations on 125 homes, with 2- to
4-k W solar systems producing power directly
to the grid.
The pilot project will enable APS to evaluate the business model and determine whether
the utility ownership model is the best structure for the customer and the utility. Further,
it will help APS better leverage solar for all
ratepayers and create opportunities for customers to enter the solar market.
What the team learns will optimize grid operations and help the company and other utilities
build a solar future.
The five-year project will serve as a field
verification of high-penetration levels of PV
Key to the understanding of
how to increase the value of solar
distributed generation is how to
move the renewable generation to
the peak hours when the sun is
not shining or when faced with a
cloudy day. To that end, APS has
implemented its first demonstration of energy storage. We’ve partnered with Electrovaya and ABB on
the Energy Storage Demonstration
Project to study a 500-k W mobile
system based on lithium-ion battery technology, installed at the
Doney Park site. We expect to
learn how to regulate energy to
reduce short-term PV variability
and provide distribution support
functions such as voltage and volt-ampere reactive support. The technical focus of this study will be
the shifting and storage of energy,
reducing rapid PV variability and
smoothing the load profile.
These studies combined will
develop a core knowledge that APS
can leverage on future solar and energy storage
integration cost benefits analysis to develop
models for cost management of integrating
solar projects into power generation.
The Sandvig 4 feeder line was chosen as the pilot project because of
the potential it demonstrated for residential implementation. While it is
short on commercial interests, APS was confident that the 400-kilowatt
Cromer elementary School array could represent commercial usage.
Copyright © 2012 by the American Solar Energy Society Inc. All rights reserved.
technical Study development
In January 2010, APS and its partners
received a $3.3 million U.S. Department of
Energy grant to study the effects of a high concentration of solar energy on the grid. Study
partners include General Electric, Arizona
State University, National Renewable Energy
Laboratory and ViaSol Energy Solutions LLC.
making de viable Generation
The Community Power Project will give
DE its best opportunity for success. The
project has been built to give real-world application and study combined with a business
model that removes the barriers to customer
participation and creates the opportunity for
high penetration using the latest technologies.
When accomplished, APS efforts will demonstrate that the DE model is a viable source
of renewable energy generation. ST