Utilities avoid a grid meltdown despite scorching heat

On June 24 and 25 consumers required more generating capacity than was available in Illinois. Utilities scrambled to purchase power from out of state, implement load management systems and prepare for possible rotating blackouts.

The heat wave that was widespread from the Rockies to the East Coast contributed to the large air-conditioning demand served by our neighboring utilities to the east and west of Illinois. These utilities were using all their capacity resources to serve their own consumers. The electric utility industry peak demands are usually established after three or more days of very high temperatures, with little nighttime relief, and during weekdays when commercial and industrial users are operating. If only a single region experiences high demand for electricity, utilities in other parts of the country can supply generation capacity, if transmission lines have the capacity to carry the power into the region with a shortage.

Carl D. Dufner, P.E.

In addition to the heat, several power plants in the state and region were not operating. Illinois Power Company's Clinton Power Station and Havana Station Units 1-5 were out of service. Commonwealth Edison's LaSalle Generating Station Units 1 and 2 were also out of service. During the same two-day period, storms damaged transmission lines in Minnesota and Iowa, and a large Ohio power plant was also taken out of service on the evening of June 24.

All of these factors made it necessary for Illinois utilities to ask consumers to conserve energy. Utilities also asked consumers with interruptible rates to curtail operations. Some utilities began voltage reductions to reduce system loads. These measures kept the utilities from calling for rotating blackouts. These small, short and controlled outages might have been necessary to prevent an uncontrolled regional blackout.

During this period Illinois electric cooperatives also participated by reducing their demand through voluntary conservation measures as well as curtailing service to consumers receiving service on an interruptible basis. Electric co-ops in Illinois operate their own power plants and have secured additional electrical generation to meet their members' needs. Of course, under conditions such as experienced this summer none of us are immune to electricity shortages.

Why can't we just buy more power? There are really two parts to the answer. If generating capacity is available, it can be purchased. The question becomes one of price. During the recent shortages, a single kilowatt-hour purchased on the open market was priced between $5 and $7 per kilowatt-hour. This is more than 100 times the usual contract price for energy bought on an hourly basis.

Utilities work together to keep the lights on during a power crisis like this summer's. For example, electric cooperatives and other utilities in Illinois are members of the Mid-America Interconnected Network, Inc. (MAIN). MAIN is a regional power pool under the North American Electric Reliability Council (NERC). NERC reviews the past for lessons learned, monitors the present for compliance, and assesses the future reliability of bulk electric systems. The Illinois Commerce Commission is also evaluating the conditions that brought about the shortages we saw this summer and may suggest changes in the operating methods of each of these Illinois systems.

Will deregulation bring an end to power supply capacity shortages? Deregulation is bringing increased competition to our industry, which means market based prices. New generating plants will not be built unless the price for electricity covers the debt and risk of investing in new power plants. Instead of regulators requiring utilities to build new generation and then setting the prices for the energy, the marketplace will establish the price. I just hope that the price is not beyond reach of the residential and small business consumer.

Carl D. Dufner is director of the Engineering Department for the Association of Illinois Electric Cooperatives. He began his professional career as a staff engineer with the Illinois Commerce Commission. He has a bachelor of science degree in electrical engineering from the University of Missouri-Rolla and is a registered professional engineer in Illinois and Missouri.

ILLINOIS COUNTRY LIVING SEPTEMBER 1998