Flooding problems delay breathing new life into defunct city hydro-electric generators

Water leaking into an aging and shuttered city hydro-electric generating facility at the O'Shaughnessy Dam , near the Columbus Zoo and Aquarium and other construction issues have put a city project to rehabilitate two small-scale generators behind schedule.

The city initially had hoped to have the project completed by mid-2023 but ran into unanticipated issues, including the need for "dewatering" an equipment chamber that was flooding due to leaks.

Stacked logs that are used to hold back water in the "tailraces," the chutes where the water is sent back into the Scioto River below the dam, were leaking and needed to be reconstructed and resealed to protect equipment from water damage. Also, rocks that had accumulated there had to be removed to create a safe space for divers inspecting the work, said George Zonders, a spokesman for the Columbus Department of Public Utilities, which serves more than 17,000 residential and business electric customers.

The leaking "was more than dewatering pumps could remove," Zonders said in an email. "...There was quite a bit of rock since the hydro unit hasn’t operated since ‘17."

Also, work crews are still "now working to assess damages that occurred when water entered the powerhouse in April," Zonders said. "We don’t yet know the extent of that damage, but we can say completion of the project will likely be delayed beyond the previous expected finish date of September."

But with those issues now largely resolved, the city Department of Utilities hopes to have two former water turbines up and running by the end of 2024.

5 megawatt hydro-power capacity

The hydro-generators, which began producing power in 1987 as part of a federal grant program to reduce reliance on foreign oil, have a combined 5-megawatt capacity — enough to potentially power several thousand homes when at full throttle.

Being at full power is dependent on the amount of water the Scioto can feed the units throughout the year. Given a high enough river, the operation will produce a maximum of 120 megawatt hours of power a day. But if dry weather means the river can't keep sufficient water flowing, generation could drop to zero at times, officials have said.

It's unclear how big of a dent the hydro units could put in the city Division of Power's carbon footprint.

The city purchases wholesale power from American Municipal Power, or AMP, a Columbus-based conglomeration of municipalities that operate a public electric system mostly in Ohio and Pennsylvania. Some of its members own and operate facilities that generate power.

The city couldn't provide its total fuel mix breakdown, but AMP's 2022 "Sustainability Report" says that 21% of its generation is from hydro, solar and wind, another 44% is from coal and natural gas facilities, and 35% is "purchased" wholesale, without listing the fuel source.

Michele Lemmon, an AMP spokeswoman, said in an email that the power purchased wholesale by AMP is provided by "PJM," the regional transmission organization for 13 states and the District of Columbia. Last week, PJM was showing in real time most of its generation - around 60% - was coming from coal, natural gas and oil, and about 30% was nuclear.

This spring, the division started for the first time getting power from new solar facilities on the South Side. Zonders said two of three new solar facilities on city land recently started producing partial power. When completed, those facilities will eventually provide about 10% of the Division of Power's current generation needs .

The city of Columbus used to be a major producer of electricity after fighting for the legal "home rule" right to do so in the early 1900s to help save its residents money. But it shuttered its aging Columbus Municipal Light Plant, whose shell still stands near Lower.com Field, in 1977.

The city experimented with its "trash-burning power plant," which opened several years later, but it turned into a costly environmental debacle by emitting cancer-causing dioxins over the South Side. It had to be shuttered in 1995, with the city stuck paying back hundreds of millions in bonds.

That left only the two O'Shaughnessy generators, which were aging, leaking and in general disrepair — and eventually abandoned in February 2017. When they went dark, the city ceased its in-house power generation program and began purchasing all its power to resell.

Bringing hydro power back in 2020

The Columbus City Council breathed new life into the generation program in 2020 by approving $15.3 million in bond money to repair and reopen the hydro operation.

Aside from leaks, the project also ran into issues with delays in obtaining generator parts, and a broken construction crane, Zonders said.

The two hydro-generators themselves, one a 3.5-megawatt capacity unit and the other a smaller 1.5 megawatts were dismantled and shipped to the Ideal Electric Company's Ohio Works in Mansfield for inspection, cleaning and minor repairs.

"The generators were found to be in good condition," Zonders said.

The power sold directly by the city's Division of Power is not to be confused with the city's much larger electric "municipal aggregation" program, Clean Energy Columbus , whose sole supplier is AEP Energy.

wbush@gannett.com

@ReporterBush

This article originally appeared on The Columbus Dispatch: Flooding problems delay breathing new life into defunct city hydro-electric generators