Attendees at the American Public Power Association’s recent Public Power Forward Summit heard from an official with Washington State-based Snohomish County PUD about the PUD’s plans to develop a microgrid that will have a disaster recovery focus.
They also heard from an executive with Florida-based public power utility Gainesville Regional Utilities, who offered details on a microgrid the utility has set up in partnership with a local health care provider.
The officials made their comments on Dec. 12 at the Public Power Forward Summit, which was held in San Francisco, Calif.
Snohomish County PUD’s H. Scott Gibson and Eric Walters, Administrative and Fuels Operations Director for Gainesville Regional Utilities, participated on a panel at the summit, “When Microgrids Are the Answer.”
In discussing Snohomish County PUD’s plans for a microgrid, Gibson said that the microgrid will have a focus on disaster recovery and grid resiliency “so that we’re prepared if an earthquake does hit the Northwest.”
Gibson noted that the microgrid project will follow on the heels of two Snohomish County PUD battery storage systems.
The PUD has installed the first two battery systems as part of a multi-year program aimed at transforming the marketplace and how utilities manage grid operations. These battery storage systems are the first to be built using the Modular Energy Storage Architecture, or MESA.
MESA provides standard interfaces between equipment components such as the power conversion system, batteries and control system. It brings more choices for utilities, reduces projects’ complexity and promises to lower costs, Snohomish County PUD notes on its website.
The Snohomish County PUD storage projects are referred to as MESA 1 and MESA 2.
The primary use case for the PUD’s Arlington microgrid is disaster recovery. “Eventually an earthquake’s going to hit the Northwest. If it does, we’ll be ready,” Gibson told conference attendees. In an emergency, the microgrid would disconnect from the main grid and help power the PUD's new local office in Arlington, Washington.
The microgrid’s “day job” will be renewable energy integration, Gibson went on to note.
The microgrid is also intended to show how electric vehicles can assist with actively contributing to the distribution system.
“We’re going to experiment with hooking up electric vehicles,” Gibson noted. The microgrid will incorporate electric fleet vehicle charging stations referred to as vehicle-to-grid or V2G. EVs “are really just another chunk of battery, another chunk of battery sitting there,” he said.
“If our big battery is starting to go dead in the event of an earthquake or in the event of a disaster,” the PUD could then utilize those fleet EVs to discharge. The plan is for the Arlington microgrid to include a 1 megawatt/1 megawatt-hour lithium-ion battery.
A V2G charging station can charge the car as well as allow for the energy stored in the electric vehicle to flow back to the grid and provide support during an outage.
An additional use case for the microgrid is to provide grid support and ancillary services when not being used for either disaster recovery or renewable energy integration.
Supply elements of the microgrid will include the grid and a 500-kW solar array. Also, “we’ll have the electric vehicles that will be able to charge and discharge. That will be part of our supply,” Gibson said. A back up natural gas-fired generator would also be available to the microgrid.
The project will also feature a Clean Energy Technology Center “where we can showcase this technology” to various parties including the public, manufacturers and other utilities “to show them how this works and how they can do it for themselves.”
The schedule for the microgrid calls for design and site preparation in 2018, construction of the microgrid in 2019, and data collection and reports in 2020.
The project has received $3.5 million in funding through a grant from the Washington Clean Energy Fund.
GRU executive details microgrid
Meanwhile, Eric Walters detailed a microgrid that Gainesville Regional Utilities has developed in partnership with a local health care provider. The microgrid is located at a University of Florida hospital site in Gainesville.
“You get multiple levels of redundancy using the microgrid, so it’s capable of being able to fully island and completely separate from the system, if need be,” Walters said, noting that the microgrid includes combined heat and power for efficient generation of utilities.
Describing how the partnership came about, Walters noted that University of Florida Health said, “We do health care well. We take care of people – that’s what we do,” while GRU does “utilities, that’s your core business.”
The health care provider said, “I don’t want to take up space and build up space in my hospital...to put a generator or to put transformers in my basement. I want to use all the space that I have to take care of people and do it as well as we possibly can.”
GRU’s response? “Well, we can run utilities – we’ve been doing it for a hundred years, let’s see if we can make this work,” Walters noted.
In detailing the results from the microgrid effort, Walters said that “We feel it’s a successful public, private partnership. It’s also garnered interest” from other large customers including a regional hospital “within our system. They’ve approached us about possibly doing something with them.”
Walters noted that since going live in 2009, “we’ve islanded 327 times for a total of about 2,100 hours of operating completely separate from the grid, supporting the hospital and all the ancillary services as a result during that time. There’s also blackstart capability that’s there. The CHP was able to achieve 80 percent efficiency, which was important to the customer.”