Officials of Willmar Municipal Utilities are continuing to study replacing high-pressure sodium streetlights with costlier but energy-efficient LED streetlights. LED stands for light-emitting diode.
The utility this year bought three Phillips-brand LED units and placed one at each of three residential locations. Also, the utility received a sample GE-brand LED unit that was placed near a Phillips unit on 23rd Street Southeast for comparison purposes Sept. 26.
Jeff Kimpling, manager of electric services, told the Municipal Utilities Commission on Monday that the GE unit's "on-the-street'' light pattern was as good or better than the Phillips unit.
Also, Kimpling said the GE unit cuts off the light pattern at the curb line. He said some people want their front yard lit up while others complain about too much light for sleeping.
Following this review, Kimpling said he ordered the purchase of three GE units for a one-year test program.
Kimpling said the utility is finally getting LED testing information from sales people after nine months of requests. He said the utility will be receiving sample units from four other LED manufacturers for testing.
Kimpling said he hopes to have a dozen lights up by the end of the year.
"We'll have purchased six of them now,'' he said. "We would like to do a section of a longer street and get 6 or 7 of them up in a row. We've got a couple of possible streets targeted for that.''
Kimpling said prices remain in the range of $400 to $450.
Wesley Hompe, general manager, said LED technology is advancing relatively rapidly.
"A couple of years ago when people are asking us about LEDs, we honestly could say they were not ready for prime time,'' Hompe said. "They're getting close to ready for us to do except the price point is still relatively high compared to what we can get existing lights and that's why we're doing this test and looking at all the different patterns.''
Hompe asks commissioners, City Council members and utility customers to report what they think about the LED units. The light produced by an LED is whiter compared with the light from a high-pressure sodium, which has a brownish tint.
"Once you get to a certain point, I'm sure we're going to have people ask us are you ready to do this as a program and replace high-pressure sodiums with LEDs. One day that might be. We're moving a lot more in that direction lately because they've gotten better,'' said Hompe.
Kimpling said the utility will consider a number of factors if switching to LEDs. LEDs are said to last from 50,000 to 100,000 hours compared with high-pressure sodium that lasts about 15,000 hours. A streetlight is used about 3,500 hours per year.
Also, a high-pressure sodium bulb stops emitting light when it burns out compared with the light from an LED that gradually dims with use. However, an LED uses about 45 percent of the energy of a high-pressure sodium, explained Kimpling.
Kimpling said the city has about 2,500 street lights. Replacing all high-pressure sodium lights with LEDs would cost a couple million dollars.
"We're not going to jump with both feet on the LED right now,'' Kimpling said. "The utility is diligently checking them out and trying to find if it's acceptable to use right now.''
In other business, the commissioners traveled by bus to observe unloading coal at the power plant; visited two of three substations, which convert incoming high-voltage power to useable lower voltage power; the northeast water treatment plant; service center; and power plant switching yard power transformer.
