Independence Day proved to be more than just hot, with NPPD's customers setting an all-time energy usage peak of an estimated 3,036 megawatts (MW) Wednesday.
The new all-time peak bettered a previous record of 2,851 megawatts reached the day before, July 3. Prior to this, NPPD's last all-time peak was 2,671 megawatts set on July 30, 2006.
"NPPD utilized the diversity of all its power plants and resources, generating power with nearly every type of fuel available (nuclear, coal, wind, natural gas and water) to meet our customers' needs," said NPPD Energy Manager Ron Thompson. "We also purchased power from the energy market when necessary."
While operational programs are in place to reduce the amount of power NPPD may need to generate for customers or curtail customers' loads with their permission, NPPD did not make any voluntary load reduction requests yesterday and was able to cover customers' needs with its own power plant resources or energy market purchases.
Yet, such a great amount of electricity carried across Nebraska's transmission system, along with the possibility of fluctuating voltages on the transmission lines, can tax system transformers, substations, and other equipment associated with power delivery.
Brief outages can occur if power lines become overloaded, and NPPD urges customers to conserve energy when possible.
Because high temperatures are expected through the rest of this week and weekend, customers are encouraged to conserve electricity, especially between 3 and 8 p.m. when energy use is at its highest. Some of the easiest ways to conserve energy are to:
"Collectively, every little bit can help," Thompson said. "Imagine if the nearly 1 million Nebraskans ultimately connected to NPPD's electrical grid turned up their thermostats one or two degrees or ran their electrical appliances like washers, dryers, dishwashers, etc. after 8 p.m. or before 8 a.m., we would likely see reduced demand on the system as a whole."
NPPD's system operators manage much of Nebraska's electric grid outside of the Omaha and Lincoln areas. NPPD works in close partnership with the public power utilities that purchase NPPD's generation and deliver it to their customers.
Together, the utilities monitor the electrical load needed by each utility and try to mitigate or adjust the load on the lines to handle the varying customer demands as efficiently and effectively as possible.
"We are constantly assessing what is driving our load," NPPD System Control Manager Ron Gunderson said. "Irrigation demands in one area of the state, coupled with air conditioning loads in nearby communities, can put great demand on the system. However, good rainfall can reduce the need for irrigation and slightly reduced temperatures in another area of the state can decrease the demand from air conditions and, in turn, reduce load on the system overall."
Wednesday, transmission lines in both the north central part of the state and around the area of Gothenburg were heavily loaded. NPPD saw a number of transformers and sub-transmission lines approaching their limits, but in most cases, such as with Dawson Public Power District and Southern Public Power District, NPPD was able to work with its wholesale partners to move load to keep the loading within limits.
There were a couple of outages related to sub-transmission lines exceeding their capability, which resulted in customer outages. Load was transferred to other sources to permit the customers service to be restored.
"Considering the extremely high loads that were experienced, the system performed remarkably well," Gunderson said. "NPPD and its wholesale partners' personnel did an excellent job of managing the transmission and distribution system during this difficult period."