The lingering power outage in New Orleans and surrounding areas served by the vertically integrated power company Entergy caused by Hurricane Ida is just the latest example of the lack of resilience in much of our nation’s power systems. One way to mitigate power disruptions is to develop more microgrids – isolated generation and delivery systems that can operate independently in a limited geographic area from the traditional regional grid.
Microgrids are especially useful for maintaining power to critical infrastructure like hospitals, telecommunications, and water treatment plants. But residential homes and apartment buildings can also benefit from microgrids, typically rooftop solar and battery storage systems generating a few hundred kilowatts that can be used to power entire neighborhoods separately from the larger electricity system.
Microgrids are a closed loop between generators and users. These islands of power can supply a large city using traditional power plants generating several megawatts or they can be as small as a neighborhood system connecting a dozen or more rooftop solar-plus-storage systems. The key is that a microgrid can operate without being connected to the broader distribution system – though it can be coupled with the distribution network as well.
Onsite generation is often more efficient and reliable because the electricity is used where it is produced, which reduces the amount of power that has to go through the transmission and distribution systems, where some of the electricity is lost.
Microgrids offer a number of advantages over larger macrogrids. They are able to more easily integrate renewable energy resources and their isolation allows them to withstand extreme weather events like Hurricane Ida. They can also improve reliability by adding flexibility to management of supply and demand, alleviate grid congestion, and reduce peak power requirements.
Entergy had an opportunity to invest in microgrids and other distributed energy resources (DERs), including roof-top solar and energy storage systems, in New Orleans several years ago. Instead, the company decided to build a utility-scale gas plant that wasn’t even able to run in the aftermath of Hurricane Ida.
Nearly all the consumers who had installed solar and storage systems in their homes were able to ride out Hurricane Ida without losing power. Residential energy systems not only give customers a source of power, but those same systems can be used to reduce peak demand on the grid and help keep supply and demand balanced.
Microgrids currently provide less than 0.2 percent of electricity nationally, but their capacity is expected to more than double in the next few years. The federal infrastructure bill being considered in Congress would provide funding for the development of more microgrid projects.