The city of Cordova in Alaska is a microgrid, withstanding earthquakes, tsunamis, avalanches, volcanic eruptions and winter superstorms to deliver power to 2,700 residents and fishing and tourism industries.
Cordova has historic collaboration with the U.S. Department of Energy (DOE) that changed the city’s electrical system into a model for resilient and modern technology. Through a series of projects, Cordova Electric Cooperative upgraded its microgrid just as the National Renewable Energy Laboratory (NREL) upgraded its research capabilities, resulting in a match of grid innovation both research and deployment, DOE said.
Cordova occupies a peninsula in the Gulf of Alaska. All its electricity comes from two hydro plants on either side of the peninsula or from diesel fuel that is barged in. These two energy sources lacked the flexibility to supply Cordova’s unique loads — which can multiply four-fold when fishing boats offload their catch. In 2017, Cordova sought a technical collaboration with DOE through the Grid-Modernization Laboratory Consortium (GMLC) program. The collaboration would be the largest GMLC grant to date at $6.2 million from DOE.
GMLC launched exactly as NREL was building out the Advanced Research on Integrated Energy Systems (ARIES) grid research platform. Across five years of work, the researchers updated Cordova’s metering infrastructure, control and operations. Their journey toward an advanced microgrid helped push the ARIES platform to new milestones in grid emulations, DOE said.
From May through September, salmon, halibut, cod and shellfish are transported and processed. This surges electricity demand and causes aggressive swings on Cordova’s electrical system. In the winter, heating and avalanches add different stressors. Cordova’s electrical system did not have the sophistication to prioritize loads, which prompted the electrical cooperative to focus on real-time grid sensing and controls.
“Not all loads in Cordova are created equally,” explained Mayank Panwar, project lead and power system engineer at NREL. “Under certain circumstances, the cooperative might want to maintain stability by shedding load, but it lacked the visibility and management tools to do so strategically.”
The first order of business for Cordova was to upgrade its infrastructure. With input from NREL, Pacific Northwest National Laboratory (PNNL), Idaho National Laboratory and Sandia National Laboratories, and funding from the DOE Office of Electricity’s Energy Storage Program, the cooperative deployed a mix of commercial microgrid technologies: around 1,200 smart meters to measure and control energy at individual buildings, six phasor measurement units for monitoring generation and substations, GPS clocks to synchronize millisecond-scale measurements, microgrid controllers, and a 1-MW battery energy system. Then NREL assisted in making everything work from the system perspective.
“The objective is to serve loads, as high capacity as possible,” Panwar said. “Real-time sensing gives us a full picture of the whole grid, and advanced metering gives us more opportunities to open and close switches and prioritize loads, such as a hospital. Now the Cordova system can reconfigure automatically, taking into account extreme events, load priorities, and more.”
Integrating thousands of new energy assets is not straightforward, but with ARIES, Panwar and team could mimic Cordova at NREL in Colorado.
In a test of ARIES capabilities in 2021, the NREL team recreated Cordova’s microgrid in the lab using the same controllers and smart meters, along with real-time digital simulations of Cordova’s system. Within this replica microgrid, they designed a system-management approach that suited customers and loads and that Cordova could swiftly and smoothly deploy. To validate it further, NREL and PNNL built a virtual “superlab” that synced assets at both laboratories for live, remote experimentation. This gave Cordova the confidence it needed to update its microgrid management.
“The advanced metering infrastructure and load management approach has sharply improved our customer service platform,” said Clay Koplin, chief executive officer of Cordova Electric Cooperative. “We didn’t have a lot of flexibility on the grid before, but now we have the microdata and platform to control devices, provide hourly visibility to customers, and improve reliability overall.”
Remote experiments did not stop there. Having already built much of Cordova’s microgrid in the lab, researchers then went full digital twin in 2023. They began streaming data from Cordova’s system to fully emulate the microgrid with ARIES assets and developed fast-timescale models to capture any grid stability issues. A particularly intensive effort for the digital twin included the full-fidelity modeling of Cordova’s hydropower resources, funded by the DOE Water Power Technologies Office.
“These older hydropower plants don’t really have design data, so we have to use operational data instead and supplement it with machine learning,” Panwar explained. “It’s important to model the plants in detail because the sensitivity to operations becomes greater as the system becomes more complex — even to the extent that water deflects off the turbine is important.”
A roundup of the project — which is named RADIANCE and was part of the GMLC Resilient Distribution Systems lab call — occurred in summer 2023. For the city and DOE, RADIANCE has been a success. It achieved its target of resilient grid investments, deployed through modern energy devices and demonstrated through field validations.
Technology transfer is another major outcome of the project. Metering infrastructure and lithium-ion batteries are common solutions for microgrids, and now there exists an example for remote resilience. Cordova’s microgrid deployment has been documented — including the microgrid controls, cybersecurity plans, digital twin, project design and integrated team process — in published articles by participating laboratories and universities.
To the extent that Cordova’s journey is applicable elsewhere, its lessons will spread with the help of participation from organizations like NRECA, the University of Alaska Fairbanks, the Alaska Power Association, the Alaska Center for Energy and Power, and the DOE Arctic Energy Office, DOE said.
The success of RADIANCE for Cordova and the establishment of a digital twin offers a promising foundation for future projects to reference. For Koplin, opportunities abound to continue Cordova’s energy evolution. Another phase of GMLC funding is imminent, and after a recent visit to explore the breadth of ARIES capabilities at NREL, Koplin envisions more applications with ARIES.
“I was impressed by the quality of ARIES equipment and the way it was used,” Koplin said. “It’s a super diversified utility in one small campus, and of course the modeling resources there are exceptional. I see the opportunity to do what we’ve done with RADIANCE but with other technologies. We have the data and tools to really tune this digital twin and work toward a smart city architecture.”
Apart from a fully established digital twin environment, complete with hydroelectric emulation, ARIES will soon have a controller hardware-in-the-loop capability to experiment on tens of thousands of physical devices at once. Through RADIANCE, researchers have shown that there are few limits for ARIES: Replica power systems can be designed in-lab, experiment data can be streamed from sites, and research assets can be connected across continents.
Among larger systems, one possibility is a group of networked microgrids across coastal Alaska. That is the purpose of another ARIES project named ORCA, which has been analyzing the hydroelectric opportunities of southeastern Alaska and the feasibility of interconnecting cities, including Cordova, with medium-voltage DC power. Data and findings from RADIANCE are informing the project, with ARIES serving a similar function of real-time emulation.
