The ‘Perfect’ Winter Storm at Grand Lake – February 2021 – What Happened?

The ‘Perfect’ winter storm of February 2021 left a lasting legacy in the Grand Lake area.

It was a difficult time around Grand Lake with a barrage of winter storms, ice, snow, historical sub-freezing temperatures, power interruptions and the need to vary lake levels.

Many have wondered how this all happened. The fact is that we have all suffered through what has been the perfect conditions of winter storms that brought all of these factors together to impact our lives.

Over the course of three consecutive days, we found the Southwest Power Pool footprint in an Energy Emergency Alert status.

Untill then, most people outside the electrical community had never even heard of the, but we learned real quickly how the SPP has control over the electric balancing market for 14 central states in the US, including Oklahoma.

So, what exactly is the role of the SPP?

They are the “air-traffic controllers” of the electric power grid to ensure the power gets to customers and to eliminate power shortages.

SPP monitors power flow throughout their footprint and coordinates regional response in emergency situations or blackouts.

Much like the Corp of Engineers must balance the lake levels and releases to ensure adequate water levels and control flooding, the SPP must do the same with the flow of electricity to member states.

SPP has never faced an Energy Emergency Alert Level 3 before, which is the highest alert level that SPP uses in a situation of energy shortage, and GRDA has never before been required to perform load shedding resulting in intentional controlled service interruptions under the circumstances as happened on two occasions during the cold.

So the big question was, why were the electric service interruptions needed?

These were controlled service interruptions that reduced the amount of draw on the electrical grid.

Had these controlled interruptions not been implemented, the electric systems under SPP control could have suffered from catastrophic, uncontrolled failures of the system.

The process acts as an electrical circuit breaker that turns a small area of electricity off when the system is overloaded in an effort to save the entire electric grid.

Some have wondered if GRDA must follow the SPP directives to shed load and participate in the coordinated interruptions.

All electrical power generation owners such as GRDA that are in the SPP are required to participate in the reductions, even if they have sufficient resources to meet their own demand.

The EEA 3 level indicates that the resource margins that normally exist had been exhausted.

When maximum generation capacity is less than the demand, the demand on the electric system must be reduced to match the generation capacity to keep the grid stable.

This controlled reduction allows the system to stay in balance and to ensure that service can be restored at a predictable time.

Without the controlled and coordinated interruptions, a cascading series of blackouts could occur that disrupt the grid, much like an ice storm, which creates uncertainty as to when service can be restored.

This is what our neighbors in Texas suffered, with millions of electrical customers being impacted by uncontrolled electric blackouts.

The question that has been asked by many has been, how did we get to this condition of coordinated interruption of service (load shedding)?

We were literally faced with the circumstances of the perfect storm that resulted in negative impacts on our electrical system.

Record cold temperatures are very hard on equipment and delivery systems.

Gas producers were unable to gather gas into delivery systems because of frozen equipment and compressing stations.

With limited supply, even GRDA was restricted in our ability to operate our natural gas-powered generator at full load because of the lack of enough fuel.

Plus, natural gas that was available was trading at approximately 100x of the usual prices.

The wind generators that electric companies rely on were not providing sufficient generation to help meet demand.

Extremely cold temperatures created high demands for energy with record winter peak demands.

The impacts of this situation were seen across the entire SPP footprint.

Why doesn’t this happen during peak periods in the summer?

Again, the perfect storm analogy works because you have record high demands on the electric system, such as we see during peak summer months, but we also had the extremely high demand on the natural gas system for home heating that we don’t have in the summer combined with the failure in gas delivery systems caused by extreme cold temperatures.

Limited availability of production means that generation and heating load create a demand that exceeds supply.

How does an electric company such as GRDA determine the power to be reduced and how long does it last?

GRDA is required to file a plan for load shedding with the National Energy Regulatory Commission as a mitigation strategy.

The predetermined plan places our customers in groups and the transmission system operators work down the list to match the reduction requirements with the load on individual delivery points within that load shed group.

A rotating pattern is continued throughout the emergency reduction period.

The goal was to keep the interruptions to one hour or less and then go to the next group until a directive is received from SPP to restore all interrupted loads. 

With lake levels being normal on Grand Lake last week, why did GRDA open floodgates resulting in a drop of lake levels?

The simple answer was to increase lake levels on Lake Hudson, which was below normal levels, to increase the pool level on that lake.

At one point, 21 floodgates were open at Pensacola Dam’s spillways.

This allowed GRDA to increase generation of electricity through hydro-electric generators on Grand, Hudson, and Holway lakes at a time when the needs for electricity were so high in the region.

While the reduction of reservoir elevations could have an impact on boat docks and increased hazards due to lower lake levels, this action was taken to provide for additional electric generation in the SPP footprint during a time of extreme and ongoing winter weather conditions.

It has not been since 2011 that we have had a winter storm that made the impact on our area that we faced in February 2021.

It will be one to be remembered.

As we look forward to warmer temperatures and better weather, we appreciate the fact that our local communities and state agencies have risen to the challenge to ensure the negative impacts of these events were as minimal as possible.

Grand River Dam Authority

Leave a Reply

Your email address will not be published. Required fields are marked *