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New WPU system should lessen costs

WORTHINGTON -- Residents may notice lower utility bills during the coming years, but what they should not notice is any drastic temperature change when Worthington Public Utilities begins regulating their air conditioning units.

The utility is implementing a load management system for its more than 3,500 customers with central air conditioning. The system requires the installation of Demand Response Units, small boxes that will be mounted to the side of a customer's home near his air conditioning unit.

The DRUs provide WPU with the ability to control air conditioning by disengaging the unit's compressor, but residents shouldn't note any difference, said WPU Manager Scott Hain.

"Inside your house, your fan is still running and there's still air coming out of the vents," he said. "We do not want our customer to be uncomfortable or inconvenienced."

Similar systems have been used in Luverne and Marshall for more than 20 years.

In Worthington, air conditioning units will be regulated for a few hours a day, two or three days per month. During that time, the compressor will shut off for 8-15 minutes each hour, and Hain said residents should not notice a change of more than three degrees in their homes.

Only 250 DRUs will be placed this summer, and customers will be notified in advance of installation.

Installation will continue into the fall and is slated for completion in summer 2012. Residents may opt out of the system for a fee.

System benefits

DRUs save the utility money by allowing it to reduce its peak electricity usage, which determines power cost.

"If we can just cut off the peak of that mountain a little bit, it's one less power plant they'll have to build," said Pat Demuth, electric superintendent. "If we can put off construction of another power plant for five to 10 years, it's ultimately a conservation tool."

Hain estimated the system would also save as much as $450,000 in 2011, allowing the utility to pass its cost savings onto the customer.

"Purchase power and transmission costs have increased dramatically, and that has resulted in a fairly significant retail rate increase," he explained, saying the two factors account for 90 percent of the WPU's operation and maintenance budget. Use of DRUs could trim as much as 40 percent from those costs. "The quicker we can get these installed, the quicker we can start saving money," he said.

Local electricians began installing DRUs in the homes of city staff and city council members last week; it is hoped a test run will allow WPU to work out any bugs before bringing the system to the general public. Demuth said DRUs do not damage AC units and may actually protect them from overheating in the event of an electrical problem.

Hain said the DRUs could allow the utility to better use its backup generator in a power outage by diverting power from air conditioning units to provide electricity to the rest of the home.

That way, "at least you got light and your sump pump will work so your basement won't flood," Hain said.

'Smart meters'

The utility is also deploying a community-wide Advanced Metering Infrastructure/Automated Meter Reading system this summer. All residents' electric meters will be replaced with "smart meters" and other equipment that allows for two-way communication between WPU and each electric meter.

All meter readings used for billing purposes will be collected in a single day. It will eliminate the need to dispatch personnel throughout the month to perform unscheduled readings at locations where customers are moving in or out.

"We'll be able to give people a final read on their electricity and generate a final bill while we're standing right there," said Hain of those moving from the community. "They can pay their last bill and they're done."

As technology develops, the system also will allow WPU to send information to its customers that pinpoints their energy use on an hour-by-hour basis and permits them greater control over usage.

"They can say, 'I don't want the washer or drying to be able to run if cost is above 15 cents a kilowatt hour,"' Hain explained.

Eventually, water meters will operate the same way.

"If they use a lot of water on one night an alarm will go off in our office that says 'high usage,'" explained Customer Service Manager Vida Iten. It would allow WPU employees to monitor potential problems like a burst water pipe and inform those vacationing or wintering out of town.

The full-time employee who did meter readings will be able to use his time elsewhere and the elimination of two contracted readers will create cost savings.

Total cost for the AMI, AMR and DRU projects is $1.66 million; there is no equipment or installation charge to customers.

Contact Worthington Public Utilities at 372-8680 for more information.