SOLAR TODAY - May 2012

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.

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.