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Load management glitch cuts the cooling

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news Worthington, 56187
Daily Globe
(507) 376-5202 customer support
Worthington Minnesota 300 11th Street / P.O. Box 639 56187

WORTHINGTON -- Shortly after 5:30 p.m. Tuesday, Barb Fuerstenberg had sent the last of her daycare charges home and was starting to make supper when she noticed it had gotten quite warm in the house.

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"I was just sweating," she said about the indoor climate. "(Husband) Steve came home and said, 'Why is it so hot in here?' We looked at the thermostat, and it was 79 degrees inside."

The fan was still running on their home's cooling system, but it wasn't cool air that was blowing around. They called a repairman and were told that there had been a lot of such calls, and the earliest an appointment could be scheduled was Friday afternoon.

But the problem wasn't with the Fuerstenbergs' air conditioning unit. The malfunction they experienced on one of the hottest days so far this year was with the load management system implemented by Worthington Public Utilities. Many air conditioners across the town were intentionally disabled for a much longer period than is the norm for the system.

"What I can tell you --and we're still digging into it --is there was a glitch in the software. The system did not work the way it was supposed to," said Worthington Public Utilities Manager Scott Hain. "The system, if it works properly, people don't even know their system is being controlled. It went unnoticed for a while, but once we realized the issue existed, we stopped the control scheme altogether."

The utility load management system is being implemented across the community, and currently about 1,800 homes in the city-- including the Fuerstenbergs' -- have the control system on the air conditioning unit. By controlling the load on days of peak usage, the utility hopes to save customers money in the long run, and the goal is to eventually have every eligible home in town participate in the load management program.

"With these deployments, WPU staff go out and identify the eligible homes that have external disconnect on their air conditioning systems," Hain explained. "They hang a brochure on the door that explains the program, why we're doing this, states the policy. It's a condition of service, but the customer can opt out by completing a form, and there is an opt-out charge, which is essentially what it costs the utility overall by not being able to control that unit."

The opt-out charge is what it costs to produce one kilowatt of summer demand and one kilowatt of transmission, which is currently $27.73 per month.

"The reason we implemented the plan this way with the opt-out charge is through a reduction in our purchase power and transmission costs, we're going to incorporate savings into our retail rate," Hain said. "If I'm participating in the plan and you're not, and I'm saving the utility $27.73 for that month, that savings is going to be calculated into the retail rate, but you're going to pay the $27.73 we didn't save that month because your unit wasn't controlled.

"The whole reason behind it is to keep rates down. That's why we did it," Hain continued. "Our wholesale costs have increased dramatically over the years, and actually on a wholesale basis they've gone to seasonal rates, so our demand in the summer is significantly higher than in winter. I saw this coming three or four years ago and started looking into this. We could have sat back and done nothing and just passed the increases along. But as a utility we wanted to be proactive, so we wanted to implement a program and start saving money on the wholesale side so we can keep rates down."

Until the problem that occurred Tuesday is rectified, Hain said the load management system will not be activated.

"Typically, we will only control two or three days a month, depending on the weather pattern," he said. "All we're trying to do is avoid that peak day of the month. Our control time is typically going to be starting at noon and running until 6 or 7 at night. The intention is when an air conditioning unit goes under control, it disables the condenser from running. The furnace fan continues to run so the air continues to circulate, just not creating the cool air, but you still have cool air in the vents. The off cycle is intended to be short enough where, by the time the air starts to warm, the compressor is able to cool the air again."

With a lot of warm weather yet to come this summer, Hain is hopeful the problem will be quickly rectified and the system can go back to doing what it was intended to do --save people money on their utility bills.

"We're going to get it corrected," Hain said. "We certainly apologize for any convenience."

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Beth Rickers
Beth Rickers is the veteran in the newspaper staff with 25 years as the Daily Globe's Features Editor. Interests include cooking, traveling and beer tasting and making with her home-brewing husband, Bryan. She writes an Area Voices blog called Lagniappe, which is a Creole term that means "a little something extra." It can be found at http://lagniappe.areavoices.com/.  
(507) 376-7327
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