Microgrids

What is a microgrid?
A microgrid is a small electric system that combines local energy resources and control technologies to provide power to a defined area. Microgrids typically remain connected to the main grid, but they can operate independently.

The controller serves as the lynchpin of the microgrid; it can activate demand response components, as well as control generation and storage resources to balance the system’s load with the resources available.

Purpose
A microgrid can improve system reliability by avoiding prolonged and rotating blackouts during and after storm events. In addition, microgrids:

  • Serve as a resource that can be called on during times of peak demand
  • Provide a learning opportunity that will help discover future uses for microgrids and their components
  • Help reduce power supply costs by providing an alternative source of power generation and storage

North Carolina’s electric cooperatives are piloting two microgrids:

The Ocracoke Island microgrid, located on North Carolina’s Outer Banks, began operation in February 2017. The North Carolina Electric Membership Corporation installed the microgrid in partnership with local cooperative Tideland Electric Membership Corporation, along with support from North Carolina’s electric cooperatives.


Source: The Sanford School of Public Policy at Duke University

Ocracoke Island’s remote location leaves it vulnerable during weather events and isolated from central power generation sources. The microgrid will support better power reliability for the island, serve as a resource that can be called on during times of peak demand and allow for the testing of system components to discover future uses.

The microgrid components include a controller, solar panels, battery storage, internet-connected thermostats, water heater controls and a diesel generator.

The Butler Farms microgrid, located in Lillington, NC, is a microgrid project that integrates components owned by North Carolina’s Electric Cooperatives with resources owned by the farm and seeks to incorporate alternative energy sources, including biogas, solar and battery storage. The farm has existing generation used to support its power needs during times when service has been interrupted, and it also sells power produced from renewable sources, including swine waste and solar, to its electric cooperative, South River EMC.

The goal of this pilot is to learn more about how a microgrid located on a member’s property can be incorporated into the electric cooperatives’ distribution system, and it also serves as a case study for the ways agribusiness and utilities can work together to develop solutions that are mutually beneficial and support both industries as well as quality of life in North Carolina’s communities.

Components of this microgrid include the controller, solar panels, a Samsung battery, biogas generation and a diesel generator.