Could Microgrids Rescue Rural Co-ops and Customers from Outages?

In some ways, the service area of the Anza Electric Cooperative in southeastern California resembles a large, landlocked island. It encompasses almost 700 square miles of high desert at an elevation of 4,000 feet and is sparsely populated. Along with 20 irrigation loads, there are just 3,900 homes, schools and businesses that use the power that Anza Electric Co-op provides. Similar to an island, the region depends on a lifeline to the “mainland” – in this case, a single Southern California Edison line bringing electricity from Arizona Electric Power Cooperative, or AEPCO, in Cochise, Arizona, Anza’s sole power provider. AEPCO owns and operates the Apache Generating Station at Cochise, Arizona, and is part of the Arizona G&T Cooperatives (AzGT).

If anything happens anywhere along that line, the people who depend on Anza are out of luck. “It’s a single line through forests that can get very windy,” says Barry Brown, executive director of engineering and transmission maintenance at AzGT. “A tree comes down, a car hits a pole, and there’s an immediate outage.”

Such events occur all too frequently, and, when transmission is interrupted, lights go off, businesses shut down and the individual wells most homeowners depend on for water stop working. “Everyone in our area is dependent on electric power for everything,” says Kevin Short, Anza’s general manager. Anza, moreover, has experienced recent load growth and resulting capacity issues even when lines aren’t down. Building a second line could help ensure a steady flow of power to the area – but at a prohibitive construction cost of at least $35 million.

To put off that expenditure as long as possible, Anza, AzGT and strategic partners – including CoBank, a national cooperative bank – are in the final stages of planning a back-up microgrid that would use solar power and battery storage to provide some electricity to Anza members when the main power line fails. “We would be able to feed at least one circuit at a time, especially the circuit that runs through our little town, to keep services open,” says Short. “The markets, the gas stations, the cell towers. And we could rotate that capability to Could Microgrids Rescue Rural Co-ops and Customers from Outages? all four of the circuits leading out of our substation.” The batteries of the microgrid could also serve as a hedge against increasing demand on Anza’s capacity-limited system.

Solar Plus Storage Equals Reliable Power

Anza doesn’t have to go it alone as it works on the design of the project, which it hopes will be ready for vendors to bid on soon. If all goes well, the microgrid could be up and running by the end of the year. The National Rural Electric Cooperative Association (NRECA), AzGT and Sandia National Laboratories – a major contractor for the U.S. Department of Energy (DOE) – all are contributing time and expertise. CoBank, which works with both Anza and AzGT, has provided essential support.

“This project paints the perfect picture of a win-win-win for everyone,” says Tamra Reynolds, CoBank’s regional vice president for electric distribution in the southern region.

Anza already has a solar installation that can produce two megawatts of AC power, with room to add another one-and-a-half megawatts of solar right next to the existing array. “We wanted to explore the concept of a microgrid here, deploying batteries along with the remaining part of the solar project, and leveraging all of that as a generator if the sun is shining when we have an outage,” says Short. The battery storage, tied into the Anza substation, could also send extra power into the system during times of peak usage.

Because the sun does shine so often in this part of California, solar power has become increasingly popular, with some 200 co-op members installing their own distributed generation systems. “Altogether we have about a megawatt of ‘behind the meter,’ member-owned solar,” Short says. And while the power generated by those installations won’t be a primary component in the planned microgrid, it does feed into the Anza system when a homeowner’s solar array produces more than it needs for that co-op member’s own use. “So that does effectively leverage the member-owned generation on the other side of the meter,” says Short.

Leaping the Hurdles

As planning for the microgrid project moves forward, Anza’s partners are playing crucial roles. “One of our primary goals as a generation and transmission, or G&T, provider to distribution co-ops like Anza is to provide service and find solutions that work for them at the lowest possible cost,” says AzGT’s Barry Brown. AzGT’s engineering staff can help with technical issues of planning and setting up the microgrid, and it can also help facilitate financing, leveraging its relationship with CoBank, for example.

CoBank provides working capital and interim capital needs for AzGT, which in turn can help Anza and the other distribution cooperatives it serves meet the needs of their members. “The most important thing is that AzGT is able to help Anza find a solution that will be unique, innovative and reliable – and come at a very inexpensive cost to the co-op and its members,” Reynolds says.

If this microgrid project comes to fruition, it should serve as a model for other small co-ops in rural areas that might benefit from a similar set-up. “They’ll get the benefit of understanding how a microgrid can work with the rest of the electric grid as a whole,” says Reynolds.

“We couldn’t have done any of this without the cooperation we’re getting from our G&T,” says Kevin Short. “That includes helping us with the serious environmental regulations we have to comply with because we’re in California.” For Anza, the only California member of an Arizona G&T, it’s important not only to get the energy it needs but that it’s also the right kind of energy. “Importing coal into California, which we used to do, is just a non-starter now,” Short adds.

Although Anza and its partners face final hurdles in making the microgrid project a reality, Short is confident that things will work out. “Once we get the design down and the bids are in, I truly believe this will be a successful project,” he says. “I have no doubt that it will succeed.”

KEVIN SHORTis the general manager for Anza Electric Cooperative