Load Management

Load management is a tool used to help balance the demand for electricity with the ability to generate and economically purchase electricity. Dairyland and its member cooperatives save money by delaying the need to construct additional power plants and reducing the need to purchase expensive power during periods of high demand.

Dairyland is a member of the Midwest Independent Transmission System Operator (MISO). MISO ensures reliable power and equal access to electric generation and transmission in 15 U.S. states and in Manitoba, Canada. Consequently, Dairyland’s use of load management may also be affected by the energy demands and weather patterns of the larger MISO region.

Load management saves energy and money. PPCS is one of 25 distribution cooperatives whose members have reduced Dairyland’s wholesale power system peaks by as much as 70 MW in the summer and 140 MW in the winter through the load management program… the equivalent size of a small power plant. It does so by reducing the system’s total demand during peak use hours—generally between 2 to 6 p.m. in the summer (May-Oct.) and 5 to 9 p.m. in winter (Nov.-April). During the hot days of summer, we request members shift any flexible use of electric appliances and electronics to earlier (before 11 a.m.) or later (after 7 p.m.) in the day to reduce our peak energy use. Extremely warm or cold weather also creates a high demand on the energy system, with the increase in air conditioner or furnace use. 

Load management can involve such techniques as interrupting water heaters or air conditioners for short periods of time, and controlling when irrigation pumps or grain drying systems run. Most residential customers experience a seamless shift, with members' thermal storage hot water and dual fuel heating systems accommodating the interruption. Commercial and industrial facilities may use generators or simply reduce load for a special rate

Electric water heating: All electric water heaters are intended to operate under PPCS’ load management program. Load management of electric water heaters can occur at any time, but during the winter months they are typically interrupted between 6-10 a.m. and 5-9 p.m. In the summer, water heaters are interrupted between 6:00 p.m. and 12:00 a.m., depending on the water heater size. PPCS encourages larger capacity water heaters to accommodate the longer load management durations.

Actual times may vary slightly.

Central air conditioning: Air conditioning units connected to our load management system are cycled on 15 minutes and off 15 minutes during peak demand periods, typically between 2:00 p.m. and  6:15 p.m. during the summer months.

Actual times may vary slightly.

Electric heating: Electric heating systems that operate under PPCS’ load management program are subject to load management, typically during periods of extreme cold weather in the winter months.

Please refer to the wiring diagram which illustrates the correct installation of the current transformer (CT) sub-metering of off-peak electric. PPCS Wiring Diagram

The load management receiver is a small radio receiver that is connected to the electric water heater circuit or the off-peak electric heating equipment. During times of peak load, the receiver picks up a radio signal to interrupt power to the electric water heater, the electric heating equipment and/or the central air conditioning unit. The lights in the small window of the load management receiver indicate how the receiver is functioning.

• Green Light. The green test light will be on most of the time. This light indicates there is a proper power supply and radio signal to the receiver.
• Red Light. The electric water heater is being interrupted.
• Upper Left Red/Lower Left Amber. If you are a participant in PPCS’ dual-fuel program, a red light in the upper left corner or amber light in the lower left corner will appear in the receiver window when your electric heat is being interrupted. Absence of an amber or red light indicates normal operation of your electric heat. Another sign that load management has been initiated is that your backup source of heat will be operating.
• Cold Load Pickup. When power is restored after an outage, all load management receivers go into a 7-10 minute shutdown mode and all lights will be on. Following this phase, your system should again be operating normally.