Peak Demand

What is electrical peak demand?

Electrical peak demand is the greatest amount of electricity that a utility provider must supply to all its customers at any given time, in any one month. Prices go up exponentially per kilowatt-hour during peak demand periods compared to lower electrical load periods. Additionally, utility providers need to rely on older, less environmentally friendly power generating facilities to meet peak demand need, meaning the environmental costs go up exponentially, as well. Peak demand periods allow for less flexibility to respond to challenges to the U's electrical system, making it less sound.

What is at risk?

  • Operations - Unexpected mechanical malfunctions, which can lead to electrical outages, are more common in peak load conditions driven primarily by heat and humidity. The U's electrical system loses its flexibility to respond to system challenges as usage increases, creating a less sound system.
  • Environment - In order to meet system demand, Xcel Energy either makes energy or buys it. The more electricity customer consume, the more energy Xcel has to purchase from outside vendors. When Xcel Energy purchases its energy, they have less control over how clean it is. So, the closer customers come to peak demand, the dirtier and more costly the energy becomes. As a large key Xcel Energy customer, we take every opportunity we can to to help our partner provide clean energy.
  • Cost - The portion of the university's electrical utility cost due to peak power demand is determined each month by the one 15 minute period of the month with the highest electrical use. So, if we use 50 megawatts at 4pm on July 15 and that is the highest recorded power demand all month, then we are charged as if we had that same demand every day of the month. If the university can anticipate when electricity use is going to be high (due to a rise in outside temperatures) and ask the campus community to reduce it's use on those days, it could help avoid a higher electricity bill at the end of the month. Each megawatt of electrical use avoided during a peak period saves the U $11,290 on its monthly electrical bill.

How do you know when a peak demand period begins?

Peak demand periods are forecasted by analyzing anticipated unusually high or low temperatures, the current weather, average hourly industrial and residential usages, and known constant demands. When the University of Minnesota determines that a possible peak demand period is approaching, University Services Vice President Pamela Wheelock will alert the campus community via e-mail so that students, faculty and staff can help reduce electrical demand. During some months, unpredictable weather may prompt several peak demand period alerts.

What can you do?

The U's Energy Management group monitors the weather for potential spikes in temperatures and humidity that could lead to peak demand periods, and makes adjustments to how energy is delivered to campus that could reduce demand. Individuals and departments can help reduce electricity use during peak demand periods by closing shades or blinds that allow direct sunlight in, turning off unnecessary lights and unplugging non-essential equipment (i.e. radios, fans, water coolers, coffee pots, cell phone chargers, etc.).

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Efforts by the campus community in July 2013 helped reduce the university's electrical peak demand by 6.6 percent compared to July 2012, and helped avoid approximately $53,000 in purchased electric demand.