On any given day last week, it would’ve taken less than 10 seconds going out the door to be reminded why the media were calling PJM. The wall of heat that smothered those who ventured outside of air conditioning served as a brutal reminder that everyone wanted the same thing: to get cooler and know reliable power was going to be there.
Each day, as PJM saw temperatures rise, the peak power use increased in lock-step, culminating in a new record peak use on Thursday, July 21, when PJM’s 58 million consumers used 158,450 megawatts (MW) of power. (In one hour, people in the PJM region used roughly the amount of power that Switzerland uses in a typical day. One megawatt can power about 1,000 U.S. homes.)
Although demand and temperatures were high the next day, Friday, PJM did not set another new record peak demand. Friday’s peak demand was 151,562 MW at 3 p.m. (eastern).
PJM called for some load management (demand response) on Friday in several transmission zones in the Mid-Atlantic region. PJM used load management to deal with local transmission/generation issues and to ensure sufficient reserves over the peak hour. Under the load management program, PJM members sign up their own customers that, in return for payment, voluntarily agree to reduce electricity use when needed.
As a result of those efforts, the grid held up well.
PJM issues its daily load forecast for peak power use through Twitter at http://Twitter.com/pjminterconnect.