Microgrids have the potential to serve as laboratories during the world’s ongoing transition toward a decarbonized economy. They also may have the ability to improve grid stability and resiliency in the long run, by design — an attractive feature that has become even more important as the spotlight has turned to maintaining critical infrastructure under pressure.

The Pacific Energy Assurance and Renewables Laboratory (PEARL) project in Hawaii is an example of that potential. The PEARL microgrid, being designed and built by Burns & McDonnell at Joint Base Pearl Harbor-Hickam, is the first of six microgrids planned to boost energy assurance, resiliency and cybersecurity on the island of Oahu. The project is expected to be completed in August 2020 and will help defend the mission posture of the F-22 fighter campus.

Its capabilities include solar photovoltaic integration, battery energy storage, and the ability to transition to islanded operation instantaneously with less than a 10% voltage drop to critical loads. It is also intended to complement Hawaii’s 2045 goal for 100% carbon-free energy sources.

Building a 100% carbon-free grid means having a distributed supply that doesn’t necessarily match the load. Power flow from solar or wind resources can change directions suddenly with the weather. If the grid starts to destabilize, the PEARL microgrid will island itself from the utility without loss of critical power, and it will stabilize and operate everything behind it. It could potentially prevent a catastrophic failure by islanding the unstable renewable source into the microgrid.

Detecting potential problems and instability from intermittent renewables can be easier to see in smaller loads instead of at the macro level. The idea is to island portions of the grid in the event of voltage destabilization. By operating in a microgrid, you can take more active control when necessary. Then you reconnect to the grid when both sides are stable. Nobody loses power inside or outside of the microgrid, and stability is maintained.

Having that ability to disconnect from parts of the grid that might need repairs but can’t be fixed instantaneously also helps maintain reliability, as the microgrid continues operating with renewable generation located inside the microgrid.

The idea behind incorporating renewables in PEARL is not merely a part of pursuing the goal of being 100% renewable. It also represents an attempt to be as effective as possible with the capital being spent. Dramatically expanding the dependence on decarbonized generation over time will involve a large investment, so we evaluated where we could put renewables in the system to maximize the dollar impact and grid reliability being offered today.


Learn more about the development and delivery of the PEARL microgrid project.

Read the Project Profile

John Bothof, PE, is Pacific operations director at Burns & McDonnell. He has a diverse range of project experience that includes new base development facility and infrastructure projects, as well as the design of reliable energy systems for mission-critical facilities.