Predicting the Peak

in June 6th, 2022

By Zack Hallock, Senior Energy Services Advisor

If you’re looking to turn utility liabilities into opportunities, look no further than your electric bill. Now, what does that exactly mean for your company or business? Simply put there’s a tremendous savings opportunity for every one of us centered around a few hours of thoughtful action during the summer months. By monitoring upcoming ISO New England (ISONE) forecasts, CES consistently informs clients about the probability of an ensuing electric grid peak that can save companies five to six figures on energy bills (depending on electricity consumption). To explore what these few summer hours can mean to your business, it’s important to realize the value of CES’ peak week analysis.

Figure 1


Figure 1 represents a “CES Peak Week Analysis” showing a customer’s hourly load profile across the week surrounding the 2021 ISO-NE system peak. With customer’s KW demand represented along the y-axis and hour of the day along the x-axis, this model is an effective way to analyze curtailment actions taken over several days. In this example, we see a CES customer with on-site generation by way of Co-Gen in addition to BMS programming to curtail grid electric demand on campus for the hour highlighted in gray. This hour in grey representing the peak hour not only reflects the highest hourly electric load in a year, but also represents the most stressful hour from a grid reliability perspective.

The two orange lines representing the peak day (June 29, 2021) reflect the impact of both BMS curtailment in addition to the individual impact from their Co-Gen. The Co-Gen represents a vast majority of curtailment which is the difference between the solid orange and dotted line, effectively making the dotted line a theoretical baseline if they never had on-site generation. To put this action in financial perspective, the additional ~2,000 KW of avoided demand by the Co-Gen results in ~$150,000/yr. of avoided electricity supply charges for this upcoming power year. It is worth noting two days later, on July 1 there were extremely close ISONE loads to June 28 and CES advised clients that they could curtail like a peak day again if they pleased. July 1 turned out to be slightly lower loads or “stress” versus June 29 likely due to cloud cover entering the region in early afternoon.

Summer 2021 was a noteworthy peak considering how early it was in the summer relative to the last 15 years – in addition to the closely projected ISONE loads for three consecutive days (June 29- July 1). This tight three-day span was anticipated the week prior by way of CES’ Self-Help Demand Response program and corroborated by notices from the local utility on upcoming curtailment events. This coalescence of signals boosted confidence for the customer and allowed them to not only gain revenue from the formal utility program, but to also avoid high electric supply capacity charges for the following power year (June 2022- June 2023) by way of a lower capacity tag.

Again, your capacity tag represents your individual contribution to the grid during the ISONE system peak, also known as the most stressful hour of the year. As a ratepayer, you financially support your contribution to the grid’s stress by way of capacity charges that can either be baked into your $/kWh supply rate or separated out as a fixed line-item charge on your electric supply bill. Evaluating your ability to both actively and reliably avoid this stressful peak hour in the summer, or even future summers is key to exploring more electricity supply options.

Another interesting caveat with June 29, 2021, was that the summer’s peak hour was adjusted forward to 4:00 p.m. - 5:00 p.m. from 5:00 - 6:00 p.m. when official results were posted by ISONE in February 2022. ISONE always waits until the following spring to post official results, but often CES can identify the hour by late September when average daily loads subside well below peak summer loads. This allows customers to better understand electric costs over the next 18 months that were otherwise unknown. This possibility of official adjustments from ISONE is why CES always stresses a multi-hour response outlined in our CES Self-Help Demand Response notices. When it comes to peak hour and capacity tag avoidance, an extra hour or two can mean a six-figure boom or bust to your next electricity budget. If you’re interested in signing up for the CES Self-Help Demand Response program, please contact Nina Callanan, Managing Director of Marketing & Communications at In addition, you may also elect to receive the CES Self-Help Demand Response text message alerts by filling out this form.

As you consider your actions for this summer and beyond, reach out to your local Energy Services Advisor to learn more and participate.


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