DL's jet turbine nearly ready to fly
Public Utilities officials were pleased with a recent test of Detroit Lakes' newly-repaired jet turbine.
The turbine, which has provided backup power for the City of Detroit Lakes for nearly 40 years, ran very well and sounded better than it has in a long time, said Utilities Superintendent Curt Punt.
"The engine operated flawlessly during this run," Punt said in a memo to the Utilities Commission, which met Tuesday.
Repairs were done in Windsor Locks, Conn., and cost about $190,000. The Detroit Lakes utilities department spent another $25,000 to upgrade the small building on Highway 10 that holds the turbine.
The turbine was operated for just under two hours on April 21, for the benefit of workers with Professional Power Products, Inc., who will replace the unit's control system.
The city will spend an estimated $294,000 on a new control system for the turbine.
The purpose of the run was for PPPI "to document operating characteristics of the unit to be used in programming of the new controls and to aid in troubleshooting the start-up," Punt said.
The turbine was taken from a jet aircraft, completely refurbished and installed in Detroit Lakes in 1968.
During the test run, the turbine saw loading slightly over 10 megawatts -- better than normal -- and produced 10,700 kilowatts of electricity for the energy grid.
In all, the utilities department expects to pay between $510,000 and $560,000 for the entire project. The city expects to have the new control system completed next month, and have the turbine fully operational by late June or early July.
The city will lease the turbine to Missouri River Energy Systems, one of its power suppliers, for about $2 million over 12 years.
Missouri River uses the turbine occasionally to keep electricity flowing during times of peak power usage.
After paying for insurance, the No. 1 fuel oil that powers the turbine, the repair project, and other expenses, the city will clear at least $1 million, and probably more, over 12 years.
The project will pay for itself in about five years, if the turbine remains in good running condition, Punt estimated.
The turbine is capable of producing 9-10 megawatts of electricity per day, enough to power key parts of the city in an emergency, but not enough to keep the entire city supplied -- that requires 25-26 megawatts on an average day.
Peak load for the city is about 33 megawatts, Punt said.
The repair project involved replacing blades that had been damaged by chips of paint, pieces of metal and other debris over the years. The turbine was still running well, but risk was that a blade would come loose and cause major damage to the engine.
A new turbine would provide about 40 megawatts per day and cost $10 million to $12 million, Punt said.
Work on the building will include welding, cleaning and painting. The turbine sucks in a lot of air, and so the building has a large air intake vent, which will be cleaned and painted.