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HU looks to instrumentation to reduce start-up noise
Hastings Utilities electric production staff members are looking into ways to minimize the noise during the start-up of North Denver Station No. 4 and No. 5 electrical generation units.
The Southwest Power Pool has called Units 4&5 into service more frequently this summer than the recent past to bolster electric production reliability on a nationwide basis. The Southwest Power Pool is a Regional Transmission Organization based in Little Rock, Arkansas that exists to provide reliable power and competitive electricity prices throughout their Midwest footprint.
It is up to the Southwest Power Pool when the plants operate.
NDS 4 and NDS 5 operated continuously from their respective completion dates in 1957 and 1967 until WEC 1 was operational in 1981. The NDS units have been in intermittent and reserve status since then. Because NDS 4 requires a 48-hour notice to being called online and NDS 5 has a 72-hour notice, Hastings Utilities has had to begin the start-up process at times that have been inconvenient to neighbors, including Sunday afternoons.
Noises can come from the operation of the plants at various times throughout start-ups and normal operation. The main source of noise in plant operation is caused by the release of pressurized steam that expands when it reaches an area of lower pressure.
Proper plant operation requires venting and draining from high-pressure steam lines throughout the operation to maintain chemistry and remove solids and air from the various systems. The noises during start-up occur when we vent and drain our high-pressure steam lines for extended periods as the unit warms.
Currently, the steam venting and draining process is longer because new instrumentation is not in place at NDS to help monitor start-up temperatures.
Without that, electric production employees err on the side of caution and incorporate a longer warming period for boiler protection.
That new instrumentation is ordered and is scheduled for installation during the upcoming winter. The instrumentation should shorten the time and intensity of the noise emitted.
Once the new instrumentation is in place, Hastings Utilities will have a better idea of how much noise to expect to emit during operation.
Further noise reduction options will continue to be explored to help mitigate disruption to neighbors. Hastings Utilities is also looking into ways to notify residents when Units 4&5 will be called into service.
“We are continuing to review procedures to ensure operations are efficient, safe and causing as little disturbance as possible as we move forward,” said Derek Zeisler, HU Director of Energy Production and Supply.
Published Date: 09/ 1/2023