Reminiscing on the summer’s heat waves... so far

As anticipated in our Summer 2024 Demand Expectations, it has indeed been a Cruel Summer so far. Heat waves have dominated ISOs in North America, leading to record-breaking temperatures in numerous cities and even a landfalling hurricane that caused week-long power outages. The energy grid has been put to the test, with summer demand already exceeding expectations in some regions. But summer is not over yet. With a short break from the heat, thanks to recent milder temperatures, let’s take a look at what we’ve seen so far.  

CAISO

It has been a scorching summer for CAISO. The heat began intensely in mid-June and has remained consistent throughout July. The heat is widespread throughout the state, with inland cities experiencing the most extreme temperatures exceeding 100 degrees for days on end. Temperature records have been broken in cities throughout the West.  

• Palm Springs recorded its hottest temperature ever at 124 degrees.

• Death Valley reached 128 degrees on July 6^th, breaking the record for that day.

• Las Vegas, a CAISO neighbor, saw its hottest temperature on record at 120 degrees on July 7^th. The city also experienced three consecutive days with temperatures above 118 degrees and seven days in the first week of July where daily high temperature records were tied or broken.

Excessive heat warnings have been continuously issued by the National Weather Service due to temperatures reaching over 110 degrees and nighttime lows above 80. The heatwaves have heightened the risk of wildfires, as seen with the destructive Park Fire currently ablaze in California.

This month, CAISO has seen its highest demand peaks of the summer so far. In 2023, demand peaked on August 16^th at 44.5 GW, which has already been surpassed this year.

• Early July: Peak demand was 43.7 GW

• July 23rd: Peak demand was 44.6 GW

• July 24th: Peak demand was 44.8 GW

In this extreme heat, Amperon consistently outperformed CAISO’s demand forecast. For example, Amperon’s forecast for July 23^rd was 1.52 times better than CAISO’s forecast with an Absolute Percentage Error (APE) of 2.22% at the peak demand hour. These are the highest demand peaks of the summer so far, with more time to reach CAISO’s forecasted July peak of 46,244 GW.

Despite the heat, CAISO has not issued any Flex Alerts this summer during these triple-digit heat waves. In the past two years, CAISO has added 11 GW of clean energy to their grid, with a significant amount being battery storage. These additions have ensured sufficient supply to meet power demand during scorching days, with battery dispatch reaching approximately 7.5 GW at peak demand on July 24^th, likely setting a new dispatch record. As of July 10^th, CAISO has 9 GW of battery storage connected to the grid, nearly 4.5 GW more than this time last year. Batteries are added to the grid to help ensure supply stability at volatile times, and we are seeing these succeed firsthand in CAISO this summer.  

Temperatures are expected to soar once again in the first week of August, with predictions well above normal for this time of year. Anticipate more high demand in CAISO and potential grid stress, especially when renewable generation is weak.

Northeast

Mid-June and July have been exceptionally steamy in NYISO and ISONE. As a Bostonian, if this heat is the new summer normal, more houses and apartments need central AC installed.  

More records were broken during the mid-June heat wave.  

• Bangor, Maine reached 96 degrees on June 20^th, a temperature not seen in nearly 100 years.

• Boston, Massachusetts tied for the hottest summer ever. High temperatures stayed in the mid to high 90s for days. On June 19^th, the city recorded its highest temperature ever for that date at 98 degrees.

The NYISO forecasted demand peak for the summer is 31,541 MW. The highest demand peak so far was around 29 GW on July 8^th. Although, this settled higher than both Amperon and NYISO’s forecast, Amperon’s peak demand forecast still outperformed NYISO’s, being 1.07 times more accurate. The ISONE forecasted demand peak for the summer is 24,553 MW. On July 16^th, demand peaked around 24.2 GW. Amperon’s APE at this peak demand hour was 0.51% which was 2.06 times better than ISONE’s forecast.  

The sustained high temperatures caused typical grid stress and elevated energy prices across the evening peak in several zones. With another heat wave expected going into the first week of August, both regions still have time to reach their expected summer peaks.

PJM and MISO

Three words: Hot weather alert!!! PJM issues these alerts when temperatures are expected to surpass 90 degrees, preparing transmission and generation facilities for increased electricity demand.  

• Mid-June: Saw the first of the PJM heat waves. Friday, June 21^st, was the hottest day of this five-day stretch, with demand peaking at 147.5 GW. Amperon’s APE at this hour was 0.82%, which was 1.46 times better than PJM’s forecast at this maximum demand hour.

• Mid-July: Demand reached new heights. On July 15^th and 16^th, peak demand exceeded PJM’s summer demand outlook of 151 GW. Amperon’s forecast outperformed PJM’s demand forecast, with APE of 1.09% on the 15th and 1.45% on the 16th at the peak demand hours. Amperon’s average MAPE (Mean Absolute Percentage Error) for these days was 1.88%, beating PJM’s MAPE.  

The National Weather Service issued excessive heat warnings for these events since high temperatures were expected to be in the high 90s or even above 100 degrees in certain regions. Washington DC experienced a record-breaking three-day stretch of temperatures 101 degrees or higher July 14-16, which has not been seen since 1930!

Additionally, MISO has also faced significant heat waves throughout the summer. MISO’s summer demand forecast peak is 123 GW, with even more generation available to meet this high demand. So far, MISO reached a peak of approximately 117.6 GW on July 15^th. At this time, Amperon’s APE was 0.14% for the peak demand hour, HE17. The next two weeks are expected to be much hotter than normal for the central US, meaning there is still time for MISO demand to climb even higher.  

AESO

Wildfires have been a persistent issue during the past few summers in Alberta. Last year, the sky in NYC turned orange from the wildfire smoke traveling all the way from Alberta. This year, wildfires are once again causing problems, combined with the intense summer heat waves—a double whammy. The pattern continues with record breaking heat throughout AESO.

• Edmonton experienced the longest heat wave on record, with seven consecutive days of high temperatures above 30 degrees Celsius in mid-July.  

• Calgary endured eight consecutive days where high temperatures above 30 degrees Celsius.  

To put this into perspective, both cities usually average fewer than four to five days a year where high temperatures reach 30 degrees Celsius. This summer, both Edmonton and Calgary have seen temperatures well above this threshold for days on end.

On the hottest day, July 22^nd, Amperon's APE at the peak demand hour (HE17) was just 0.03%, significantly outperforming AESO’s forecast for that day. On July 17th, which saw the second highest demand of this period, Amperon’s peak demand forecast was approximately 1.08% more accurate than AESO’s.

The heatwave season is far from over. While the grid enjoyed a bit of relief this past week with cooler temperatures, the forecast predicts a return to intense heat for much of the country this week. Regions across the country must brace for continued high demand and potential grid stress. Amperon's forecasts are crucial in navigating the extreme heat ahead, ensuring that grids can manage peak loads and maintain stability during the hottest periods.