(click image to enlarge 84k .jpg) Scott Tonderum shows off Graettinger's new standby diesel generator. The 1,860-kW generator will ensure the reliability of the Iowa town's electric utility system. It will also provide peaking power.

Graettinger, Iowa, ensures reliability with new diesel standby generator

Like many municipal utilities, Graettinger, Iowa, wants to ensure its system's reliability in these uncertain times.

Toward that end, the city bought a 1,860-kilowatt diesel fuel Cummins Onan generator to help keep the power flowing no matter what happens. "We'll use it for peaking," said Scott Tonderum, Graettinger Municipal Utilities manager. "But it's also for protection. It's backup for the town. It will provide generation if we lose our interconnection."

This ability will fill a gap in Graettinger's system, which has been operating with less than full standby capacity. According to Tonderum, "We had two old generators for standby and peak demand. When there was an outage, it would take 30 to 45 minutes to start them up and bring them on line. Also, we were unable to generate our own peak load, so when we had an outage, we would generate what we could, and then start rotating our feeder lines," he said. In other words, the utility would use rolling blackouts.

The new system starts four seconds after a power disruption, reducing down time to under a minute and avoiding lengthy outages.

"The system starts four seconds after a power disruption, reducing down time to under a minute."

"The system is all microprocessor-controlled for starting and running the engine. The engine will start automatically if our interconnection is disrupted. That will mean a shorter period of disruption for our customers."

The Onan generator's PowerCommand control package was a major selling point, according to Tonderum. It also allows Tonderum to monitor system operations from his office. Generator reports go directly to his PC, eliminating the need to walk through the plant and monitor engine operations.

This is helpful for another reason, too. The Graettinger Power Plant doesn't have a large staff.

"With only two employees, there are times when we're both out of town," Tonderum explained. When an outage occurs, the employees must first return to town and then address the problem. In the past, this led to outages lasting up to three hours. The automatic startup function will solve this problem.

The system is the first of its kind installed at a municipal utility in the United States, making Graettinger a pioneer. While this caused some initial apprehension, the town now feels comfortable with the added reliability the generator offers.

The generator was installed and began operating in spring 2001. So far, the city hasn't experienced any emergencies. "We used it one time for peaking this summer," said Tonderum. "It ran for a nine-hour stretch one day. We ran it other times for testing and training."

While the city may not need to call on this backup system frequently, it ensures Graettinger and his customers will have energy available when it's needed.

"The biggest advantage of having this system is protection for our town and our ultimate customers, which include two manufacturers, a grain elevator, and a senior care facility. Before, we couldn't even carry our load during peak. Now we can generate all the electricity we need and push the excess out on the grid. We've eliminated rolling blackouts."