On Wednesday, June 1, 2016, ISO New England (ISO-NE) announced it has begun electronically dispatching wind and intermittent hydro resources interconnected to the New England grid through the implementation of its Do Not Exceed (DNE) Dispatch Project. Until now, variable resources like wind and intermittent hydro were unable to respond to ISO-NE’s electronic dispatch instructions like conventional generators due to their reliance on fluctuating weather or river flow conditions. Instead, ISO-NE permitted wind and intermittent hydro to run at-will under normal grid conditions and provided manual curtailment instructions when necessary. These actions typically do not impact the market clearing price. As of May 25, 2016, however, wind and intermittent hydro participating in the DNE Dispatch Project can receive electronic dispatch instructions and set real-time prices in the region’s energy market.
While the DNE Dispatch Project permits wind and intermittent hydro to receive electronic dispatch instructions, the process for these resources is still somewhat different than the specific output level dispatch instructions conventional generators in ISO-NE receive. ISO-NE’s DNE Dispatch Project establishes an individual output band for each participating wind and intermittent hydro resource. The upper bound, or DNE limit, is set based on the total amount of intermittent generation the system can handle. The lower limit is set at the individual resource’s economic minimum limit. A participating resource can operate freely between the economic minimum limit and the DNE limit but, as the name suggests, may not exceed the DNE limit. Beginning June 1, 2019, DNE dispatchable generators with a capacity supply obligation will be required to offer into the Day-Ahead Energy Market based on their expected generation. ISO-NE anticipates that its new system will improve wholesale price formation and increase utilization of low-cost renewable resources in transmission-constrained areas.
