This particular power outage was due to a “Load shed event”, which is a last-resort controlled power outage ordered by SPP, the regional grid operator, in order to prevent larger, uncontrolled blackouts. It’s a way to balance supply and demand for our power grid. This event occurred because the temperature was higher than usual (89 degrees was the reported high in Shreveport that day), during a time when planned generation and transmission maintenance was underway. Load shed events are often associated with extreme weather, like Hurricane Laura in 2020 and Winter Storm Uri in 2021.
In this case it was the Southwest Power Pool, or SPP. The Southwest Power Pool (SPP) is a regional grid operator responsible for maintaining electric reliability in a 14-state area, which includes the SWEPCO service territory in Northwest Louisiana affected by this load shed event. The majority of Louisiana is within the grid operator footprint of another regional transmission operator, MISO.
SPP coordinates with their members to maintain grid reliability and plan maintenance outages. SPP members include investor-owned utilities, electric cooperatives, independent power producers, large industrial customers, and others. On April 26, SPP detected instability on the grid in Bossier and Caddo parishes, and alerted SWEPCO to reduce its electricity use by 140 MW in order to avoid a larger outage of 2,000 MW, which could have resulted in power outages for over 100,000 people.
There’s a lot we still don’t know, but what we do know about the load shed event in Caddo and Bossier parishes is that in the days leading up to the load shed, some of SWEPCO’s transmission and generation assets were offline. That means one or more power plants were offline for scheduled maintenance, and transmission lines were down to allow for upgrades. We’ll know more soon, SPP and SWEPCO will conduct an analysis to get more details.
Typically, maintenance events like this are scheduled well in advance, and take place in the fall and spring when there is usually less power demand. However, the weather was warmer than predicted, which means customers were using more power than usual as they cooled their homes and businesses. In this case, SPP’s forecasts did not identify the need for SWEPCO’s power plant and transmission infrastructure to reconnect to the grid in order to avoid the load shedding.
Load shed events can have significant financial and community impacts, in the form of spoiled groceries, loss of access to power dependent medical devices, missed sales opportunities for small businesses, lost wages, and more.
There are still more details to come about exactly what facilities and transmission lines were offline, and why SPP did not previously detect a possible grid instability. As we wait for more details, it’s a good time to take stock of what we do know. We know that there are methods to reduce the risks of these kinds of events from happening in the future. Expanding transmission capacity, increasing distributed battery storage capacity, and establishing energy efficiency programs can all help to reduce the likelihood and severity of future load shed events. For example, expanding transmission capacity would allow for more power to flow to population centers. If we think of our electric grid as a highway system for power, adding more transmission capacity is like adding more lanes, or adding new highways altogether, alleviating congestion and allowing people or in this instance, power, to arrive at its end destination quicker and without as much congestion. Incorporating energy efficiency programs is similar to reducing the number of cars on the road. By having more energy efficient homes and buildings, we reduce the demand for power.
Power outages are challenging for communities, which is why grid operators and utilities must use all the tools available to reduce their likelihood. The Alliance will continue to advocate for expanded transmission capacity and energy efficiency programs so that future load shed events will not be so deeply felt by our neighbors.
