However they are defined, everyone agrees community microgrids provide benefits. Centralized utility systems and aboveground distribution lines expose customers to regional and local outages, “and while they are highly reliable, centralized utility grids can’t ensure local resilience,” notes Peter Douglass, project manager for the Microgrid Institute, a collaborative organization supporting global development of microgrids and distributed energy assets through market development and analysis, regulatory and financial models, and microgrid feasibility, structuring, and deployment.
Such resilience is vital for health and safety facilities, street and traffic lights, municipal water and wastewater utilities, telecommunications, military bases, and critical retail facilities such as gas stations, grocery stores, and pharmacies.
“Community microgrids promote the resiliency and reliability of local power distribution systems,” he points out, adding that they also improve environmental performance and integrate renewable technology.
According to the Clean Coalition, community microgrids use efficient load design, including local balancing and load flattening, to reduce costly peaks and transmission costs.
They minimize water use and promote land preservation by siting local renewables on rooftops, parking lots, and other underutilized spaces within the built environment. They establish a scalable solution spanning one or more substations.
Other benefits include the establishment of a foundation for more precise and efficient grid operations, a pathway for utilities to thrive in the distributed energy future, and a systemwide approach to reduce dependency on vulnerable, inefficient, and expensive remote generation and associated transmission infrastructure, adds Lewis.
Additional benefits are affordable and stable energy prices as well as a stronger local economy through attracting private investment, job creation, and keeping energy dollars close to home, according to the Clean Coalition.
A key feature of community microgrids is their capability of operating independently from the utility system in an island mode in the event of a utility failure.
There are community microgrids which provide value in terms of total energy costs “where we can shift the solar consumption—which we call ‘self-consumption’—so that rather than back-feeding solar to the grid, they’re consuming more of it themselves,” says David Miller, director of business development for Greensmith Energy.
“Or we can set it up where we are actually depending on the jurisdiction to be able to provide grid services with the microgrid, with frequency response, or spinning reserves where we get value from the microgrid during hours where there is not a reliability need.”
More complicated multi-zone community microgrids have the ability to operate as a single system and, if necessary, each zone can operate independently, Douglass points out.
“Distributed generation has a shorter distance to reach the end-user and less energy is lost to heat as it travels over power lines,” he adds.
Additionally, many microgrids use combined heat and power (CHP) or cogeneration systems designed to achieve higher fuel efficiency than is offered by separate power plants and heating systems.
“Microgrid control technologies optimize the use of energy and result in higher efficiency than the utility system as a whole,” says Douglass. “Advanced community microgrids reduce overall energy requirements and ensure that energy can be used as intelligently as possible.”
Advanced energy systems help foster economic growth and reduce community dependence on distant or imported energy sources, Douglass adds.
“Exploitation of local renewable energy resources can keep more of a community’s energy dollars in the local economy,” he says.