Reliable electric service is growing in importance to our lives and to the economy, but threats to reliable electricity are also proliferating.
The threats seem to be coming from an ever-growing list of sources: wildfires, extreme cold, record floods, hurricanes, extreme storms, and cyberattacks. Fortunately, innovation and technology are keeping pace with the threats. Increasingly, businesses, utilities, government agencies, hospitals, as well as universities and research organizations are installing microgrids to ensure that their electric power will continue to flow even if the surrounding grid goes down.
Green Mountain Power in Vermont recently announced plans to break ground this spring on a microgrid in Panton that will combine 4.9-MW of solar panels with a 1-MW/4-MWh battery storage system. The microgrid project is part of Green Mountain Power’s plan to create resiliency zones in towns that are affected by outages caused by severe weather.
On the other side of the country, Kaiser Permanente is building a microgrid at its hospital in Ontario that includes 2.2 MW of solar panels, a 1-MW fuel cell, and a 9-MWh battery.
One of the aims of the California hospital microgrid, as with the Vermont project, is to demonstrate that a microgrid can provide reliability without the need for fossil fuel generation.
In Chicago, Commonwealth Edison is building a microgrid in the city’s Bronzeville neighborhood that will include 5.5 MW of gas-fired generation, as well as 50 kW of solar panels and a 500-kW battery system. It is designed to provide low emission power if grid power suffers a disruption.
These projects represent just a small sample of the wide variety of microgrids being deployed today. And while they vary in many ways, including design, purpose and even size, they all share a common characteristic. Microgrids are designed to be self-sustaining with the ability to isolate or “island” from the surrounding grid during an emergency and return to synchronized grid operation after the emergency has passed. How any individual microgrid achieves that goal varies widely, however.
Microgrids come in a wide variety of configurations that allow them to be tailored to meet specific customer needs. One of the key defining characteristics of a microgrid’s design is the generation source it uses.