Corncob test burn at Willmar Municipal Utilities power plant goes well, general manager says
WILLMAR -- A preliminary test burn of corncobs in a coal-fired boiler at the Willmar Municipal Utilities power plant went well, says Bruce Gomm, utility general manager.
The utility bought 450 tons of cobs from area farmers last fall and burned from 10 to 12 tons two weeks ago in unit No. 3, which normally burns coal. A full test burn will be June 17. The utility will use the results to determine if cobs will help the utility comply with a state mandate that requires all utilities by 2025 to obtain at least 25 percent of energy needs from renewable resources.
It's part of state and national efforts to produce more electricity from renewable sources such as biofuel and wind.
Gomm told the Municipal Utilities Commission on Monday the cobs were burned before the boiler received annual maintenance to determine if any complications would arise with the test burn and the temporary equipment installed to feed the cobs into the boiler.
No. 3 is the plant's main boiler and was designated for the corncob burn. The cobs were blown into the side of the boiler through the view port and it worked better than expected, Gomm reported.
"It all performed very well,'' Gomm said. "There was a time period of about two hours where between 30 percent and 40 percent of fuel by BTU going through the boiler was cob. We need to do a little bit of tweaking on our auger system, but other than that it works well.''
The big test will come once the unit is returned to service in four to five weeks. Gomm said a continuous burn-type application is planned to test and check stack emissions.
"We did get some preliminary data with our monitoring equipment and it performed pretty much like we expected as what the engineers told us should happen,'' Gomm said. He said a testing company will perform detailed results for the permanent application from the Minnesota Pollution Control Agency.
"As they say at conferences, we had some green electrons running around town,'' Gomm said.
Also Monday, the commission approved the low bid of $1,025,896 from Power Generation Services of Anoka to repair the turbine for No. 2 boiler. A higher bid of $1,617,000 was received from General Electric.
The turbine was taken to Power Generation for repair, but repair was more extensive than anticipated and exceeded the $250,000 budget. Power Generation has made other repairs at the Willmar power plant, said Gomm.
In related business, the commission approved a recommendation by Gomm to transfer $800,000 from the utility improvement replacement fund to the general fund to pay for the turbine repair. Gomm said the fund will be replenished during the next several budgets.
Jeff Kimpling, manager of electric services, reported on discussions that he and other utility staff had with the city Public Works Department on potential use of LED lights for street lighting. Kimpling said he'd keep the City Council's Public Works/Safety Committee informed on the latest LED developments.
The city has almost 3,100 street lights equipped with high-pressure sodium bulbs. LEDs use less power and are said to last longer, but cost significantly more and cannot be serviced by utility staff, according to Kimpling.
Also, the LED light pattern is directional compared with a broader pattern produced by high-pressure sodium, explained Kimpling.
LEDs are successfully used, however, in city traffic signals and operate at one-third of the cost of other bulbs.