Earthquake Worries Prompt Oregon Cities to Install Microgrids for Resiliency
Beaverton is the second Oregon city that will embrace microgrids for resiliency, working with utility Portland General Electric (PGE), which says it plans additional partnerships with cities.
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PGE’s microgrid projects are designed in part to provide resiliency if and when an earthquake hits the Oregon coast. Scientists have predicted that an earthquake as big as 8.0-9.0 could strike the region soon.
“For us in the Pacific Northwest, we’re all concerned about the Cascadia event, essentially the mother of all earthquakes,” said Kevin Whitener, PGE’s project lead for the Beaverton Public Safety building project.
PGE’s first microgrid project, a partnership among PGE, the city of Portland and Portland State University (PSU), aims to offer microgrid support in a series of park statues that will charge cell phones and store emergency supplies. The first of these PrepHub projects will be installed at PSU and is expected to be completed early next year, said Melanie Erdmann, spokeswoman for PGE.
The city of Beaverton’s project is the second. The city was eager to do a microgrid — so eager that, after hearing that PGE was developing a storage/microgrid program, left space in the design of its Public Safety Center, now under construction. Ultimately, PGE came on board and approved the project, said Captain Eric Oathes, project manager for Beaverton’s Public Safety Center.
More resiliency projects on the way.
“In addition to the Beaverton Public Safety Center, we are negotiating a second energy storage microgrid and anticipate it will be energized in 2020. Like the Beaverton Public Safety Center project, this project will also be designed to support community resiliency,” said Erdmann.
“We’re in conversations with both public and private entities — including other cities — but nothing is formalized or approved by the OPUC (Oregon Public Utility Commission) at this time.”
For Beaverton, the main benefits are redundant systems, a backup generator and the battery storage system, which provide emergency power supply to the building. The Public Safety Center houses the city’s emergency operations center (EOC), said Oathes.PGE would like to see microgrids “strategically placed” throughout the company’s service territory, she said.
PGE would like to see microgrids “strategically placed” throughout the company’s service territory.
“It is very important to have a functioning EOC during these times of need for the city and the community,” he said. “The battery supply will be powered from a large solar array on the top of the building and we can use the generator and solar power, hopefully indefinitely, when emergencies arise.”
The city will own the building, 300 kW of solar PV, and a 1,000 kW diesel standby generator. PGE will own the 250 kW storage system, which it will use, when available, for frequency control, said Whitener.
“The battery can discharge to the grid to supply that service system wide,” he said. “It might also respond to low voltage in local areas.”
In Beaverton, the microgrid could island for 21 days, said Whitener. PGE and the city chose diesel backup because in the event of a large earthquake, gas lines would rupture. The diesel will be stored underground.
The utility chose a four-hour battery based on a financial analysis, said Whitener. “When we ran the financial analysis on the benefits of storage, we used to be looking at one and two hour systems. The benefits are now penciling out better at four hours and six isn’t bad. But four is the sweet spot for us,” he said.
The average duration of a utility scale lithium ion battery is 1.7 hours, but the batteries can store energy for four hours, according to the US Dept. of Energy.
The Public Safety Center’s load is fairly small, about 200 kW when it peaks. During the summer, the building could “operate indefinitely” on solar and storage, without starting the diesel generator. At night, the peak is as low as 100 kW, so the battery in the summer could operate all through the night and pick up solar when the sun rises, Whitener said.
Rendering of Beaverton’s Public Safety Center. Courtesy City of Beaverton
On average, the solar can handle about 40% of the building’s load year round.
The system’s building management system will shed load if there’s little solar available or if diesel is running low.
Non-emitting resource for Oregon utility
And if energy from the battery is available, PGE will use it as a “non-emitting resource,” which is capacity that doesn’t emit carbon dioxide or other greenhouse gases. Whitener noted that it’s impossible to determine the energy mix delivered to a battery, but according to state regulators, batteries are non-emitting. Other resources that are non-emitting are pumped storage, renewable energy plus storage and geothermal energy, said Erdmann.
In another project, PGE has launched a smart grid test bed with the aim of testing dispatchable distributed energy resources (DER), said Erdmann. In three areas, North Portland, Milwaukee and South Hillsboro, PGE over the summer began a demand response program for residents. The most successful event took place Aug. 20, when 34,500 customers earned rebates, bringing PGE 7.726 MW of demand response.
“We will roll out additional programs to test and learn what programs work for them. We want to establish a virtual power plant through behavioral changes and having people use devices like smart thermostats and batteries,” said Erdmann.
The Beaverton microgrid includes a battery system from Powin, a microgrid controller from PXiSE Energy Solutions, a Caterpillar diesel generator, solar PV from SolarEdge and a PGE plant controller, for dispatching grid services, from Nikos.
Microgrids benefit cities and utilities
Under the partnership, both parties benefit. PGE owns and can use the battery for grid services. The city of Beaverton gets resiliency, said Whitener.
“What we are providing to the city is the resiliency they want. We’re optimizing the use of their solar rather than burning diesel during outages,” said Whitener.
The microgrid will island during emergencies, but the system will help PGE with grid services and on-peak power when it’s operating normally, said Oathes.
“The community benefit is that when the major disasters/emergency occurs the city will be able to maintain critical operations to provide necessary services to the community,” said Oathes.
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