Balancing the supply and demand of electricity

By: Marshal Albright, Cass County Electric Cooperative president & CEO

The power grid is like a heartbeat; it needs to remain in sync or rhythm to keep the power flowing. If either gets out of sync or arrhythmia, help is needed ASAP.

During the recent cold snap in February, the Texas power grid was out of sync because demand exceeded supply. Every grid performs a balancing act - all the electricity supplying the grid must equal the amount coming off it. When the balance of supply and demand is out of sync, the power grid’s frequency, generally at 60 cycles per second, will get compromised.

Let’s say the frequency falls below a certain level, perhaps 59.4 hertz. That may not sound much different than 60 hertz, but if the frequency stayed under that threshold for several minutes, it could trigger a grid’s cascading failure, cause power plants to trip off-line, and damage equipment. During the Texas event, within minutes, the frequency fell from 59.4 to about 59.3 hertz, according to ERCOT (Electric Reliability Council of Texas). To raise the frequency, either electric load had to be disconnected or more power generation needed to come on. In Texas, power generation was limited due to cold weather issues at their power plants, so their only option to keep the frequency at 60 hertz and avoid a grid collapse was to initiate rolling blackouts. One report stated that during the event, the entire grid was within minutes of failure. The grid operator (ERCOT) took the necessary steps to keep the grid powered.

There is much more to this story than I can cover in one page, but two questions come to mind. Could the event in Texas be prevented, and could this happen to us?

The rolling blackouts in Texas should not have happened. In the future, lawmakers, regulators, politicians, and the public will demand their electricity generation is more resilient to weather and that fuel supplies will need to be more reliable, especially the flow and supply of natural gas.

In our part of the world, we are not isolated from such an event. Utilities are being forced away from traditional baseload generation like coal and nuclear to more intermittent and unpredictable sources like wind and solar, increasing the risk of such an event.

In January 2019, our region was on the cusp of rolling blackouts during the polar vortex. Primarily, natural gas supplies were falling short of demand, and numerous wind turbines were off-line because it was too cold. Fortunately, the tri-state area cut back on natural gas use for home heating, so more natural gas for power production became available. The grid operator, MISO (Midcontinent Independent System Operator), called for all power generation sources to operate, including all diesel generation, and asked utilities to initiate demand response to keep the grid operational.

As a nation, we must acknowledge what happened in Texas to ensure we have reliable electricity; it is a matter of national security, safety, and well-being. As we plan for our future, we must consider power generation sources that supply reliable power and remain in sync with the demand for electricity at all times.