AEI has added a feature to its AEI ISO Alerts web page to better assist subscribers looking to avoid avoiding coincident peaks with the systems like PJM that use multiple peak hours when calculating their PLC or ICAP tags.
The tables of annual peak values below each chart on the main AEI ISO Alerts page now has clickable orange buttons for each year that expand an area to reveal two new tables. The first of the two tables shows the Top 10 Peak Hours in the current year (starting on June 1st). The second table is nearly the same except that any given day can only appear once in the table. This is the PJM method for determining the "Top 5 Hours" in the year. To be more exact, PJM normalizes for weather at the end of the year, but that's not applicable for our purposes during our mid-year reporting.
In the specific case of PJM, August 19th was a good example of why this new feature might be helpful. The AEI ISO Alert morning report on that day rated it a low risk for PJM to hit a new annual peak hour. This was technically correct, but the peak load on that day did end up as the 5th highest load for the year so far (shown with green highlight in the accompanying image) even though it was almost 7% lower than the reigning annual peak. That 5th place load could have an effect on the ultimate coincident peak hour calculations that PJM will make at the end of the year because they use the Top 5 peak hours for their PLC calculation, unlike most other grid operators that only use the single peak hour.
AEI hopes that this new work will help its subscribers to better react to those borderline peaks that make their way into a PJM calculation. Work is already underway to have these loads incorporated into the morning report so that customers will know with the appropriate urgency when a Top 5 or Top 10 peak is in the forecast. AEI expects to have this variant of the morning report ready by early September.
Visit AEI ISO Alerts to learn more, to see the new Top 10 Peak Hours in action and to sign-up for this free service.