While both American Electric Power and the Southwest Power Pool made mistakes that led to a blackout under good weather conditions in northwest Louisiana, the most prominent reason should serve as a warning going forward to state policy-makers.
AEP’s subsidiary Southwestern Electric Power last month had to cut power to around 30,000 people, most in Bossier Parish, for a few hours despite no damage from weather or other sources. It had to at the behest of SPP, because there wasn’t enough power available in SWEPCO’s service area. Trying to draw too much from outside wouldn’t have helped, and more from within would have been as likely to cause cascading failures within the service area.
SWEPCO came up short because it had taken offline temporarily some generation locations for maintenance. This act had been planned months in advance with the expectation that mild spring weather would place low demand on electricity, thus the reduced capacity still could serve all demand. However, unexpectedly high temperatures in the SWEPCO service abrogated that plan and forced the blackout.