The International District Energy Association (IDEA) is promoting an expanded form of arrangement between distribution utilities and owners/operators of distributed energy facilities, in particular those with spare, dispatchable energy or capacity to provide grid support to their local utility. Long-term contracts known as Distribution Support Service Agreements (DSSAs) would allow a participating utility to access the capabilities of a local microgrid or other dispatchable DER resource to provide flexible, tailored services to meet local grid needs, for example during emergency conditions, such as extreme heat or storm-damaged power lines. An advanced semi-autonomous control centre with dynamic grid monitoring, response, and switching as well as distributed energy resource management capabilities can quickly isolate damaged circuits, reroute power flows, and dispatch several such local resources to assist the grid operator in maintaining service to the surrounding communities and to aid in restoration, or prevent local power loss entirely.
As the paper notes, there are already standardized services available from distribution-level resources external to the utility itself, such as microgrids, through fixed tariffs for interruptible load, curtailment, and retail demand response programs. The provision of such standardized products represents a present market pathway for microgrids, and one that is important to expand at both wholesale and retail levels, the white paper says. However, it adds, they can also provide additional value through locally tailored, customized products and services deserving of a new market pathway. Under DSSAs, a local utility can call local microgrids into various export profiles to support and sustain circuits facing exceptional circumstances. DSSAs can also direct islanded microgrids to synchronize and reconnect to a restoring grid without putting load on their local substations, thereby reducing the power needed for circuit restoration.
DSSAs offer a unique advantage to utilities and the communities they serve, the paper observes: ratepayers pay for microgrid services, but not the cost of building microgrids. Utilities are already called on to invest in other capital-intensive areas such as advanced distribution system control technologies, EV charging networks, and utility-scale renewable generation and storage. DSSAs offer utilities a contractual vehicle to benefit from local microgrid services without their customers bearing rate increases for the microgrids providing the service.
Furthermore, when utilities procure DSSAs, those offered by microgrids that also sustain emergency services could receive preferential treatment (and may be complemented by new public benefit fund community resilience assistance programs).
Most grid failures are experienced at distribution to midrange voltage levels, the paper notes, making it efficient to drive resilience at the grid-edge.