Arizona Public Service Company has begun testing a 1.5 MWh energy-storage system the size of a shipping container. The goal of the company’s two-year pilot in Flagstaff, Ariz., will be to determine the benefits for storing solar-generated electricity and putting it onto the grid at times when APS customers need it most. The battery could work as well for wind generated power.
“We plan to study a number of things, including how we can decrease equipment stress on high demand days and how we can provide solar energy to our customers after sundown,” says APS Director of Energy Innovation Barbara Lockwood. “This pilot has great potential to change some of the ways we deliver electricity in the future.”
The energy storage pilot will be two-fold. In 2012, the system, which was developed by Electrovaya Inc., a lithium-ion battery manufacturing company, will reside in an electrical distribution substation. The system will be later trucked a few miles up the road to support a neighborhood-scale solar power plant. In addition, Electrovaya has partnered with ABB, a power and automation technology company, to provide the power conditioning and conversion equipment for the battery energy storage system.
A video of the energy storage system can be found on YouTube at (http://www.youtube.com/watch?v=zNMclgXUUqw&feature=youtu.be).
“This system is possibly the world’s largest Lithium Ion battery in a single container” commented Dr. Raj Das Gupta, Electrovaya’s General Manager, Energy Storage Systems. “Working with major utilities represents a tremendous opportunity for us in the rapidly growing grid energy storage market, and validates the importance of our advanced battery technology and unique toxic chemical-free manufacturing process.”
In the substation, the system will store energy when it is inexpensive and the electricity flowing through the substation equipment is at lower capacity. Then, APS can dispatch the energy at times of higher demand when electricity is more expensive to purchase or produce and equipment is at maximum capacity.
“The steadier flow of electricity on peak days could keep our equipment healthy for longer periods, so we can improve reliability and keep maintenance costs down,” says APS Energy Storage Project Manager Joe Wilhelm. “In the future, if a piece of equipment fails and causes an outage, we could also dispatch energy from storage units temporarily until repairs were made.”
At the Doney Park Renewable Energy site, a 500-kW solar power plant, energy storage will help reduce the intermittency of solar power generation and help to get more renewable energy onto the grid. For example, when a cloud passes over and system output decreases slightly, APS can dispatch energy from storage to fill the gap and keep a smooth flow of generation to the grid. APS also plans to test dispatching the energy after dark.
“Energy storage can make renewable resources more reliable for operations teams and consumers. One of the busiest times on our system is between 5 and 9 p.m. That’s when many customers get home from work, turn on lights, the TV and air conditioning. However, by that time, solar systems have largely stopped producing for the day,” says Wilhelm. “With storage, we can gather solar energy during the day and dispatch it in the evening, when it provides the greatest benefit to customers.”
The 500-kW Doney Park Renewable Energy site is part of the APS Community Power Project. With Community Power, APS is studying the effects of a high concentration of solar energy in a single neighborhood as part of a $3.3 million U.S. Department of Energy grant awarded in 2010. In addition to the solar plant, 125 APS customers and a local elementary school are generating electricity from rooftop solar systems.
Flagstaff is home to several APS Energy Innovation pilots. In addition to Community Power, APS is engaged in a self-healing/self-isolating grid pilot and a distribution fault anticipation pilot. The latter two technologies help predict and manage system faults, resulting in reduced power outages and quicker repair times.
Arizona Public Service Company