Navigant Research Blog

Heat Wave Activates Utilities’ Demand Response Systems

Marianne Hedin — July 31, 2012

The 2012 summer has seen 2 weeks of brutal heat waves across large parts of the United States.  The first one occurred during the week of June 25, and the most recent one struck a few weeks later during the week of July 16.

A new 2012 peak for electrical demand, 12,836 megawatts (MW), was reached this year by Con Edison on July 17 when New York City hit 96 degrees Fahrenheit.  During the same week, the Midwest Independent Transmission System Operator (MISO), which operates all or part of the power grid in 11 U.S. Midwestern states and the province of Manitoba in Canada, reported that its entire territory hit well above historical average temperatures, contributing to record demand for power during several days.

To manage the high demand for electricity, some of the utilities and grid operators activated demand response (DR) systems to ensure grid reliability.  Con Edison, for example, asked its 3.2 million customers in the New York metropolitan area to conserve power during the steamy week of July 16.  The utility also took extra precaution by reducing the voltage used in New York City by, for example, dimming lights and letting hot water heaters take longer to heat water.  Thanks to these curtailment efforts, according to Con Edison, only 97 customers lost power, a remarkable accomplishment for a utility of its size.  At the same time, the New York ISO, which operates the grid in the state, requested that customers – both residents and businesses – who participate in its DR programs reduce their power usage.

MISO also had to take action to take some stress off its grid during the same week.  Besides declaring the need for energy conservation for 5 consecutive days, it issued numerous alerts for maximum generation by asking generators and transmission owners to put off unnecessary maintenance on the grid.  It also requested that generators in neighboring grids sell power into its system.  In addition, on July 18, PJM Interconnection (PJM), the biggest U.S.  grid operator, which serves over 60 million people in 13 Mid-Atlantic and Midwestern states and the District of Columbia, dispatched both short-lead and long-lead emergency DR in many of its eastern utilities, representing a total of 2,098 MW of capacity.

The hot weather has also kept EnerNOC, PJM’s largest aggregator, busier than usual.   So far, it has executed a record number of load-shedding programs this summer.  During the recent heat wave, it dispatched DR 32 times, accounting for about 3,000 MW of DR capacity, to its resources in 14 states, the District of Columbia, and Ontario, Canada.  Its automatic DR capability plays a significant role in enabling DR programs of many of the large grid operators, such as PJM, New York ISO, New England ISO, and California ISO.  This summer has certainly not been an exception.

With the potential for more heat waves in the coming months of August and September, aggregators, utilities, and grid operators will be able to demonstrate further that DR has become a critical resource in managing demand for electricity during peak times and to avert power outages.

One response to “Heat Wave Activates Utilities’ Demand Response Systems”

  1. Edward von Bergen says:

    I read an article in Wall Street Journal that EOS Energy Storage Systems was critical to the micro-grid batteries that were used to prevent the black-out during this heat wave. I am interested in these micro-grid batteries backup, but the cost per 1000 kWh units was posted on their literature as $160 per kWh purchase. Is that correct or is my mind mis-reading?

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