Samish Island, Washington, stretches between Padilla Bay and Samish Bay in the Puget Sound. A single distribution line, maintained by Puget Sound Energy, connects this secluded coastal community to the main power grid.
In 2017, Samish Island homeowner Bob Pavia emailed PSE after finding a contact on their website. He pitched the idea of installing a solar microgrid to provide backup power to the island fire station. “People [on Samish Island] were already getting solar,” he explained. “I asked how we could help PSE and the fire station stay online utilizing that solar.”Pavia had already discussed the concept with Fire Chief Michael Collins, who supported the idea. A resident since 1981, Chief Collins had experienced many outages, and as chief of the volunteer fire department, understood the need for dependable backup power. PSE responded positively.“They were open to the idea,” Pavia said. “One of their first questions was if the Samish Island community would support it.” Without hesitation, Pavia told them yes.Joe Do, a PSE principal engineer and technical lead on the Samish Island project, explained, “We were looking for a community to demonstrate the use of clean energy while increasing the resilience of our system.” A microgrid with advanced controls and photovoltaic (PV) generation would meet both the community and utility needs.Do approached the Samish Island project as a proof of concept for future PSE microgrids—a scalable model to guide similar initiatives. The utility had already prioritized integrating distributed energy resources and microgrids as part of its grid modernization strategy, aligned with the Washington State Clean Energy Transformation Act (CETA).
“Once we decided to have a scalable microgrid controller, the next question was, since we don’t have all the skills to implement this ourselves, who do we turn to?” Do said. “That naturally was SEL for their engineering services, as well as the controller platform.” PSE had worked with SEL for years, integrating products and solutions throughout its grid. The Samish Island microgrid required automation and a secure, reliable platform—PSE was confident that collaborating with SEL would deliver a solution tailored to the needs of the island.
Keeping Critical Infrastructure Online
PSE and SEL began working on a customized solution. The Samish Island microgrid project included rooftop PV systems from three homes, including Pavia’s, and an 8 kW ground-mounted array installed behind the fire station.During the development stage, Gabe Berbig, a Special Protection Systems automation engineer for SEL Engineering Services (ES), joined the project. He determined the optimal solution to coordinate the microgrid, battery, and PV with the main grid included an SEL powerMAX Power Management and Control System built around an SEL-3555 Real-Time Automation Controller (RTAC).SEL powerMAX is a microgrid management platform composed of protective relays, controllers, software, cybersecurity, and logic processing. The RTAC automation platform serves as the brain of the solution, providing the logic processing to coordinate all the elements of the system and continuously monitoring the grid connection, system load, and battery status.
“We landed on using the SEL RTAC solution as the microgrid controller because it speaks a plethora of communication languages, and it’s a secure OT device that integrates well with our security requirements.”
To program the RTAC, Berbig studied the KORE Power 50k W/332 kWh battery storage system that PSE selected for the project. The battery storage system includes an inverter and multiple lithium batteries. “Inverters operate differently than generators, and there are a lot of ways to apply that flexibility,” he said.The SEL powerMAX solution also allows flexibility for different use cases. During normal operation, the main PSE grid supplies power to the Samish Island residents. Any excess PV generated by the three homes and fire station connected to the microgrid feeds the battery to maintain the charge for backup power during an event. powerMAX also allows the system to transmit PV generation back to the main grid to supplement power during peak energy use.When a fault occurs on the main line, an SEL-651R Advanced Recloser Control trips the PSE recloser at the point of common coupling (PCC). powerMAX seamlessly islands the homes and fire station, allowing the microgrid to operate independently and maintain real-time load balance at subcycle speeds. powerMAX also ensures stability by continuously monitoring the system on both the microgrid side and the utility side.
PSE and SEL teams designed a custom solution that includes multiple KORE Power batteries for energy storage, an SEL-2488 Satellite-Synchronized Network Clock for precise timing, an SEL-3620 Ethernet Security Gateway, and multiple RTACs. An SEL-651R recloser control communicates with a recloser and the microgrid control system to island from and resynchronize with the grid.
During outages, the microgrid supplies power to the three homes and fire station using energy stored in the battery storage system, while the PV continues feeding excess energy into the microgrid to help maintain battery charge. The system sends email and text alerts to the households and the fire station with updates on system status and battery levels.“As an outage persists, alerts continue to go out to update the residents on the status of the battery, so they can choose to proactively preserve battery life by reducing load,” said Barr. Once PSE restores power, the microgrid control system automatically and seamlessly resynchronizes the homes and fire station with the main grid. Using SEL relays and the RTAC, powerMAX matches voltage, frequency, and phase angle to prevent equipment damage and ensure a safe reconnect. powerMAX initiates the breaker close at the PCC, which safely restores grid connection without disrupting power to the homes or fire station.
Lab and Onsite Testing Offer Broad Benefits
Before installing the system on Samish Island, Berbig and other SEL ES team members conducted rigorous hardware-in-the-loop testing and simulations using a universal power flow (UPF) simulator built on an RTAC. The UPF library provided programming tools to model the Samish Island battery storage system and its role in monitoring voltage, frequency, the recloser, and loads in real-world conditions. The tests proved successful.Once onsite, PSE and SEL performed additional testing, including transitions between grid-connected and islanded states. To avoid disrupting the community power supply during initial testing, PSE temporarily rerouted the homes and fire station to an alternate line using reclosers and simulated load with a load bank to replicate microgrid demand during an outage. “We torture tested the system,” Berbig said. “We started it up, shut it down, and ran the microgrid controls through all its sequences to be able to recover from many different scenarios.” Thanks to strong community support, PSE was able to also conduct a black-start test after connecting the three homes and fire station to the microgrid. This required a complete disconnection from the main grid—a total power shutdown—to confirm the microgrid could safely and effectively energize the users using only the battery storage system.
“I was very impressed at the amount of detail and safety aspects that PSE took to make sure everything was running safe and efficiently,” Chief Collins said. “I’ve seen other projects in industrial situations, so I know there are challenges that can come up. Yet PSE would be out in all sorts of weather—rain, sometimes under tents—trying to work out the little programming bugs that came up. It was outstanding.”
Collaboration Demonstrates the Importance of Community
During the first storm season after implementation, the SEL powerMAX microgrid control system isolated the microgrid and maintained stable voltage and frequency through five islanding events, while supporting the load of the fire station and the three connected houses. The Samish Island microgrid project strengthened the collaborative relationship between PSE, SEL, and the local community, demonstrating how small-scale projects offer unique opportunities that larger projects may not. For example, utilities rarely perform black-start testing due to the disruption it causes for customers. Given their confidence in PSE and SEL, Chief Collins, Pavia, and the other two homeowners agreed to not just one black start but three.“A lot of hands touched this project over its time,” Do emphasized. “A lot of people worked behind the curtains.”Collaborations that foster shared expertise and growth are essential as inverter-based resources and renewable energy integration become more prevalent. Barr often refers to the Samish Island microgrid as a working lab—an environment to deepen the understanding of microgrid capabilities and apply that knowledge to future projects.
“There’s an opportunity to identify and quantify all the different information from Samish. It’s a mini generation site of data.”
Berbig agreed that both teams gained important knowledge about microgrid systems. “All of [the PSE] relay technicians and engineers gave me a good sense of confidence that when I had a question or if we had a problem to solve, we had the right people for the job to get the solutions.”PSE continues to enhance the microgrid using real-time data from powerMAX and feedback from the Samish Island users. The PSE investment to deliver backup power, especially during storm season, provides residents with a sense of security and strengthens community resilience. The project reflects how PSE is committed to delivering safe, reliable power and implementing meaningful change.“Having power backup has been a goal of ours for a long time,” Chief Collins reflected. “Now we have power that’s dependable and extensive enough to keep us going, keep the lights on, and be able to get out the door to serve our community in the fashion they expect.”