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Howard Plante
Vice President of Procurement
Freedom Energy

With the summer months behind us, we’re growing increasingly more confident that the Annual System Peak is behind us as well. Although there have been a few early September days in some years that have provided a little drama, the Peak has never occurred in any month other than June, July, or August in the past 21 years, according to data from ISO-NE.

Behind-the-meter solar installations continue to cause variability and increase the difficulty for ISO-NE to forecast demand.

Late afternoon storms on some hot and humid days caused a significant drop in power consumption.

Demand forecasts on each of the days considered as potential Peaks were very close, within a few hundred MWs. There was never a day that was a clear outlier.

Utility programs that compensate end users for curtailing have increased the amount of curtailment that is implemented, further reducing demand when it is expected to peak higher.

Curtailment Notice Results

The spread in peak demand on three of the four days that we recommended curtailment was 115 MW, a 1/2 % variation. Initial ISO-NE reports indicated that July 20th resulted in the highest peak; however, subsequent reports indicate that August 4th was higher at 24,471 MW (preliminary and subject to change). Based on historical reporting, it is likely that August 4th will stand as the peak, but we’ll need to wait until ISO-NE officially reports it.

July 21st was an example of how storms impact demand. At 2 PM, demand was beginning to exceed the projection, but the storms that moved through around 3 PM reduced demand so that we could end the curtailment period earlier. (Note that if you are in a Utility program that implemented curtailment, you should follow the recommended time frame to ensure your program payments are not impacted).

Some Points of Interest

In most years, forecasted demand in the first early season heat wave has necessitated sending a curtailment notice in June. Our first notice this year was July 20, 2022.

Although we had several Heat Waves (90° temperatures for three days or more) that extended as long as seven days and record-breaking temperatures in many areas across New England, it did not result in demand sufficiently high to warrant a curtailment notice.

On each of the four days, we recommended curtailment: actual demand failed to reach the forecast, and the peak occurred later than expected (at 7 PM vs. 6 PM forecast)

If August 4, 2022 remains the peak at 24,471 MW, it will be the 7th lowest since 2001.

Historical Peak Results

The chart below not only depicts that the Peak is trending toward later in the day but also appears to be trending lower. The average Peak from 2001 through 2011 was 25,700 MW, vs. 24,833 MW from 2012 through 2022. The Peak only occurred once later than 3 PM in those first 11 years, compared to Peaking later than 3 PM nine times out of the last 11 years. Based on recent ISO data, the Peak hour of 6 PM on August 4th conflicts with the initial Morning Report data of 7 PM.

2023 and Beyond

Future years will likely continue to present additional complexity in predicting the Annual System Peak based on weather, additional renewable generation, and implementation of energy efficiency measures. We will continue to do our best to keep you apprised of changes.

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Explore other energy industry articles in our September Newsletter to help you make informed decisions for your business.

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