Ames residents see the massive structure at the end of Main Street and most recognize it as the Ames Municipal Power Plant, part of Ames Electric Services. It’s been there in some form since 1896, reliably providing power for Ames residents and businesses.

But the plant is now experiencing a generational transformation. The Ames Voice recently toured the plant with Director of Electric Services Donald Kom to learn more about it and its future.

Kom’s department includes 80 employees. Of those, 41 people work inside the plant. The citizens of Ames own the plant that serves 28,000 customers — as measured by the number of electric meters. Most of those customers are within city limits.

No property tax dollars are used to fund the plant, which generates revenue primarily from energy sales to customers and selling excess power to other utilities.

The power plant’s current projects

A project expected to cost up to $192 million will replace an aging electricity generator with three modern generators and create some capacity for load growth. The city will build it at the abandoned coal yard site, adjacent to the current plant.

If the existing units fail before replacements are ready, Ames could face energy costs in the millions of dollars per season.

The plant’s two boiler generating units, Units 7 and 8, each had a 30-year life expectancy. Unit 7 became operational in 1967, while Unit 8 started in 1982. Together, they produce 98 megawatts of electricity when operating.

While both units can burn a mixture of garbage and natural gas, Unit 7 is the primary generating unit. Unit 8 operates when the regional grid operator needs it, usually during peak-demand periods. Both units are aging and unreliable, Kom said.

Moving forward with the updates

City staff recommended building new generators because of the long-term capacity, cost stability, energy price certainty, greater system reliability and the advantage of keeping local control of the city’s power supply.

The replacements will be reciprocating internal combustion engines (known as RICE units), Kom said.

Three RICE units will be installed in the first phase. The site is designed to eventually hold six units, replacing the full 98-megawatt capacity of the old boilers and then some. RICE units start in minutes rather than hours, burn fuel more efficiently than steam boilers and emit less carbon for the same amount of electricity produced.

How much electricity is generated locally?

Currently, about 50% of the electricity generated by the plant is produced locally. Once the plant’s updates are complete in 2027, the local percentage is projected to drop by half.

Where does the rest of the generation come from?

Whenever the cost of purchasing rather than producing electricity is lower, the plant buys it “off the grid” from MISO (the Midcontinent Independent System Operator), the electric grid operator for the central U.S.

If it’s cheaper to buy power from MISO, why don’t we buy it exclusively there?

Grid prices are extremely volatile and change every 5 minutes. These prices are dependent on the regional generation operating at the time, the day of the week, the time of the day, the season, and of course, the weather.

When will the first three RICE units go online?

The first three units are expected to become operational in the spring of 2030.

Once all six RICE units are online, what will happen to the current building?

Kom said he hopes Unit 8 can be used until 2040. After that, the future of the current building, including its cooling towers, will be up to the Ames City Council.