There has been a lot of conversation lately about “microgrids.” And, given the significant power outages experienced in Maine and the Northeast this past week due to extreme weather events, these conversations are bound to increase.

But, what exactly are microgrids, and how can they help? Not everyone agrees.

In simple terms, a microgrid is a small portion of a larger electric system that is able to be “walled off” from the rest of the grid for purposes of reliability, and it would include a combination of generation and storage resources so that, when there is a system outage, the microgrid can remain running. Typically, microgrids are appropriate for critical infrastructure like hospitals or military bases.

The more technical definition of a microgrid is a group of interconnected customers and distribute energy resources with clearly defined electrical boundaries that is part of the larger grid, but can also be isolated and operated independently.

However, some use the term microgrid to mean carving certain customers or territories out of the regional electric grid so that the customers can generate and use electricity without being part of the regional grid. Under this “by-pass” model, customers could potentially avoid paying for the costs of operating the larger electric grid, which would have the effect of raising the rates of all other customers not participating in the microgrid.

Two weeks ago, on October 24, the Energy, Utilities, and Technology Committee of the Maine Legislature met to discuss legislation intended to promote microgrids. The bill, LD 257, An Act to Enable Municipalities Working with Utilities to Establish Microgrids, was originally presented last winter by Rep. Michael Devin (D-Newcastle). The bill was a “concept draft” with little detail, but purported to allow municipalities to work cooperatively to create microgrids. The bill did not address issues of cost or system by-pass. Nor did the bill define “microgrid.”

During the Committee hearing, the Committee heard presentations from Chris Johnson, a former Democratic state senator from Maine, and Paul Kando, an advocate of microgrids. The discussion focused on developing microgrids with onsite renewable energy generation and storage.

The Committee hearing was also reported on by Microgrid Knowledge Newsletter. The article included a reference to testimony by James Cohen on behalf of Emera Maine, the transmission and distribution company serving Northern and Downeast Maine. Emera Maine was supportive of certain types of microgrids, provided they were focused on system reliability and not by-pass.

Discussions on microgrids are expected to continue into 2018, including a scheduled meeting of the Energy Committee on December 7th.