Lessons Learned? - ORIGINAL CONTENT

The past two years have provided unpleasant lessons for several electric utilities and their customers. The challenge remains for those utilities and the utility industry to learn from those lessons and take actions to prevent their recurrence. Because of the nature of the electric utility industry, these lessons must also be learned by state and federal utility regulators who largely control the utilities' actions.

California utilities are dealing with aggressive state efforts to transition the state utility grid from fossil and nuclear generation to wind and solar generation with energy storage. However, the state has pushed for rapid shutdown of natural gas and nuclear generators before storage was available to replace the output of those generators during periods when wind and/or solar generator output was reduced. The result has been insufficient conventional capacity to replace the output of wind and solar generators, particularly during periods of peak demand.

Texas utilities experienced a very cold period in early 2022. The cold caused freezing of water in gas lines supplying gas turbine generators, freezing of coal piles at coal generating stations and icing on the blades of a significant portion of the state’s wind generation capacity. The combination of these effects resulted in a significant grid failure which took several days to resolve. The issues with the gas and coal plants are relatively easily resolvable with improved maintenance and insulation, but preventing icing of the wind turbine blades would require a major refitting with blades which could be heated.

The US Southeast experienced extremely cold weather on Christmas Eve, 2022. Duke Power in North Carolina was forced to institute rolling blackouts to keep the grid from failure. The shortage of generating capacity was the result of control failures at two natural gas plants and one coal plant, aggravated by the fact that the coldest period occurred in the very early morning, before sunrise, so no solar generator output was available. Again, the issues at the fossil fuel plants are relatively easily resolvable. However, dealing with the solar issue would require significant storage. Duke’s problem was exacerbated by the failure of neighboring utilities to provide power for which Duke had contracted, since those utilities were also affected by the extreme cold.

TVA also experienced problems during that very cold period with both coal and natural gas generators. TVA experienced demand approximately 35% higher than on a typical winter day, its highest demand ever. This forced rolling blackouts by some of the utilities TVA serves at wholesale. Again, the issues with the fossil fuel plants are relatively easily resolvable with improved maintenance and insulation.

Each of these situations highlights the necessity for high level maintenance of utility infrastructure, particularly during periods of expected peak demand. The California, Texas and North Carolina experiences also highlight the importance of backup generation during periods of low/no wind and solar generation availability. As intermittent renewable generation capacity increases, it will be necessary to develop new contract arrangements to assure that natural gas is available in sufficient quantities for the natural gas generators.