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Electric Grid

PACE - Electric Grid with power lines


The electric grid to provides electricity to our homes, businesses and town facilities. Our current grid performs exceptionally well, but was built and designed when power was generated solely by large plants and transmitted in one direction to customers. Today, with the proliferation of distributed energy resources (DER) such as solar, storage, combined heat-and power (CHP), energy is created in many locations and is transmitted in different directions. Moreover, today’s grid can place limits on how much renewable energy can be built, and is vulnerable to blackouts during major storms and attacks.

An important building block in modernizing the electric grid is the microgrid. A microgrid, as the name suggests, is essentially a subset of the larger grid. It comprises a range of different electric loads and distributed energy resources (DER) and can operate as a part of the larger grid or separately (aka “island mode”).

An important benefit of microgrids is resilience; by “islanding” from the grid in emergencies, a microgrid can continue providing power to critical services (e.g., hospitals, first responders, governmental functions and emergency shelters.) However, from the standpoint of the 100PercentCT project, an even more important benefit of microgrids is that they increase the “renewable hosting capacity” of the grid. In other words, they increase the ability of the grid to handle intermittent resources like wind and solar. At the current time the presence of renewables on the grid is not difficult for the grid to handle. However as renewable “penetration” on the grid approaches about 10% of the power delivered Community Microgrids will be crucial to going to higher levels of renewables.

Getting Started

Historically, microgrids have been built around a single entity such as a military base, university or company. However, a form of microgrid of particular interest to cities and towns is the Community Microgrid. The California-based non-profit Clean Coalition defines one as follows:

A Community Microgrid is a coordinated local grid area served by one or more distribution substations and supported by high penetrations of local renewables and other distributed energy resources (DER), such as energy storage and demand response. Community Microgrids represent a new approach for designing and operating the electric grid, relying heavily on DER to achieve a more sustainable, secure, and cost-effective energy system while providing indefinite, renewables-driven backup power for prioritized loads.

Key elements of the Community Microgrid are:

  • A large amount of renewable resource on the microgrid circuits,
  • A large amount of storage on the microgrid which serves both to add resiliency – but also to serve to smooth out power variability due to intermittent renewable resources,
  • A large number of businesses and municipal buildings connected to the grid – so that a given area can function even without the power coming through the substation. This is in contrast to the typical microgrid we now see in Connecticut where a single facility or entity (e.g. a University is served by the microgrid)
  • An example of a community microgrid would be a collection of key municipal facilities, a number of community businesses such as grocery stores and gasoline stations, a solar array, battery storage and a backup generator. In the future, the grid might consist of a series of interconnected microgrids.


Completing a Community Microgrid project will require extensive preparation and planning and multiple partners. An important component of a town energy plan is to assess potential sites for a microgrid. With this step complete, the town and its partners will be aware of the concept and will thus be able to move towards this architecture when an opportunity arises. Important partners in planning and implementing a microgrid include:

  • The utility,
  • Communities with successful microgrids,
  • Manufacturers of microgrid hardware, including controls, storage, solar.
  • Energy consultants and non-profits.


In Connecticut, the Department of Energy and Environmental Protection (DEEP) has conducted four rounds of a grant program for a diverse range of microgrids with a focus on resilience. This program or other funding opportunities may emerge in the future.


  • As part of the town energy plan, assess potential sites in town for microgrids. Identify high-priority loads to build around.
  • Review successful community microgrids in Connecticut and elsewhere.
  • Educate town and other potential stakeholders on the community microgrid approach.
  • Consult with your utility to determine if there are areas on the grid where a microgrid can solve a grid problem. (See link to hosting capacity map in Resources below.) This step is important because microgrids are typically an expensive proposition. If the microgrid can solve multiple problems (e.g., grid stability, disaster resilience, increased hosting capacity for renewables, and potential minimization of demand charges), the aggregate value stream may cost justify the capital outlay.
  • Engage with manufacturers of community microgrid components. These companies have the expertise and experience to complete microgrid projects and are familiar with available incentives and financing options.
  • Reach out to consultants and non-profits with microgrid experience. They may be able to provide independent advise on the feasibility of projects.


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