Medford, Massachusetts is moving forward with a microgrid designed to improve resilience for its public works department and reduce the city’s electric demand charges.
The city this week selected solar installer Solect Energy to engineer, procure, install, and service the grid-connected microgrid.
The Medford microgrid is being built around an existing 235-kW solar array that was installed by Solect through their partnership with PowerOptions, a non-profit energy buying consortium in New England.
In addition to the solar array, the project features an 100-kW/255-kWh NEC energy storage system and an emergency generator.
The microgrid will help keep power flowing if the central grid fails as well as aid city efforts to dampen utility demand charges. Demand charges, which are set based on a customer’s monthly peak load, can significantly increase costs for energy-intensive utility customers, such as municipalities and businesses.
To control demand charges, an energy customer tries to reduce electricity use when demand on the grid peaks. Microgrids assist with this strategy because the customer can use microgrid power, instead of grid power, at the crucial time. Demand charges are set based on that short period of energy use. So if customers cut back on use of the grid at that point, they lower what they pay in demand charges going forward.
Although many microgrids now act to reduce demand charges, one of the most highly touted early success stories occurred at Stafford Hill, a solar plus storage microgrid in Vermont that is owned by Green Mountain Power. The microgrid saved Green Mountain Power $200,000 when it turned on batteries at just the right time to reduce its demand during the hour that New England hit its annual peak in 2016.
In addition to cutting costs through demand charge management, the Medford project will help curb the city’s electricity expenses by participating in demand response programs, where a customer receives a credit or payment for curbing energy use when called upon by the local utility or grid operator.
A northern suburb of Boston, Medford is building the microgrid with an $833,000 grant from the state Department of Energy Resources. The project is one of several funded by the state agency to show how distributed renewable energy can make cities and towns more energy resilient.
Separately, the Massachusetts Clean Energy Center also has a grant program to foster microgrids. The MassCEC in February issued 14 grants of $75,000 each to help communities undertake feasibility studies and attract private investment.
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