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Time-of-Use Program Pays for Irrigators by Dave Wilkins, Staff Writer Capital Press - May 31, 2002

BOISE -- Some Idaho Power Co. irrigation customers have found that it pays to do most of their pumping at night.

Participants in a time-of-use pilot program reduced their collective electricity bills by $100,724 during the 2001 irrigation season, the company reported recently.

Irrigators accomplished the savings by shifting more of their energy use from peak demand period during the day to off-peak hours at night.

The pilot program, now entering its second year, provides irrigation customers varying electricity rates depending on the time of day that they operate their pumps.

In its first year the program's base rate during off-peak hours -- from 9 p.m. to 9 a.m. -- was about half that of standard irrigation power rates.

"It's actually been a pretty useful program," said Lynn Taming, executive director of the Idaho Irrigation Pumpers Association.

"The amount that's being charged during off-peak hours is so much better than the regular irrigation rate," Tominaga said. "There just isn't as much demand for the power, so you can buy it at a cheaper rate."

The pilot program has demonstrated the benefits of pricing based on time-of-use rates, the company said in a status report to the Idaho Public Utilities Commission.

It encourages participants to shift more of their irrigation power usage to nighttime, off-peak hours.

Idaho Power irrigation customers typically use about 49 percent of their total energy load during off-peak hours, but participants boosted that to 60 percent during the 2001 irrigation season.

"It works for (participants)," Tominaga said. "It saves them money and helps the power company shift its energy load."

Still, the program probably isn't for every farm because it requires putting on the same amount of water over a shorter period of time, Tominaga said.

"Your infiltration rate will determine some of your ability to do this," he said. "You're basically going to be limited to sandy soil or a sandy loam."

While participants get a substantial cost savings for irrigating during off-peak hours, they pay a premium for irrigating during on-peak hours, from 1 p.m. to 9 p.m.

The pilot program was designed to help customers reduce their power bills while at the same time helping Idaho Power to reduce power purchase costs.

The program reduced the company's power purchasing costs by an estimated $48,689 during the 2001 irrigation season, but reduced its revenue by $100,724 -- the same amount that customers saved.

"As the second year of the pilot program gets under way, the company will continue to monitor participant's usage patterns as well as the impacts of the program on the company's revenues and purchase power costs," Idaho Power said in its report.

During the first year of the pilot program, about 30 percent of Idaho Power's irrigation load was ineligible to participate because of the power buy-back program.

In addition, open-market power prices became less volatile during the summer of 2001 than they were during the summer of 2000.

"The impact of these two changes on the pilot program results will be of particular interest during the upcoming irrigation season," the company said.

Rates under the program vary this year from 2.8 cents per kilowatt hour for off-peak usage to 6.3 cents for on-peak usage. Mid peak usage -- from 9 a.m. to 1 p.m. -- will be billed at 4.2 cents per kilowatt hour.

Enrollment in the program is limited to 300 metered service points. About 180 metered service points were enrolled the first year.

The pilot program is scheduled to end on Oct. 1, 2002, and the company won't accept new participants after that date. however, customers enrolled on Oct. 1 may continue to participate until Oct. 1, 2007, if they choose.

Idaho power will be in a better position to evaluate the pilot program once results from the 2002 irrigation season are available, the company said.