A hydroelectric plant under construction for nearly seven years next to the Cannelton Locks and Dam is almost finished and is expected to begin generating electricity for customers in March, according to a company official. American Municipal Power began building the 84-megawatt, triple-unit plant on the Ohio River in 2009 at a cost then estimated at $416 million. One of the plant's three units is already making power, the AMP official said. "It is not finished, but it will be in operation the first quarter of this year," said Kent Carson, senior director of media relations and communications programs at AMP.  "Unit 1 is in the testing phase and it has been generating electricity. We're coming along. We did have hold-ups with high river levels the last few weeks. ... High water has been an issue. The facilities are designed to be overtopped, but you can't generate electricity when that happens."

The plant, which includes three rotors deep in the river channel that are turned by the flow of water to power generators, is huge, Carson said. "It is essentially like a 10-story building, with nine stories underground," he said. "You do see the top of the power house." The hydroelectric plant was built next to the Cannelton Dam, Carson said, and some water is diverted through the plant. Before the water reaches the plant's rotor blades, it runs through tube channels that gets narrower as the water gets closer to the rotors, increasing the water pressure and turning the rotors, which resemble propellers on a ship. Each rotor is about 25 feet in diameter, Carson said. That is larger than the propellers on the Titanic. The power from the Cannelton plant will eventually be distributed to 79 municipal utilities in four states, with a portion going to Paducah and Princeton. None goes to the open wholesale market, Carson said. The Cannelton plant is in the commissioning phase and nine operators have been hired, Carson said. "We're ready to go full commercial," he said. "We've had a few delays lately, but we're very pleased." AMP is currently building four hydroelectric plants on the Ohio River.

The other three are in Smithland; Willow Island, West Virginia, near Parkersburg; and one at Cincinnati to supply power exclusively to Hamilton, Ohio. The Cannelton plant is behind schedule. It was originally scheduled to be finished more than a year ago, but Carson said high river levels contributed to delays. In AMP website describes the plant this way: "The Cannelton Project will divert water from the existing Army Corps of Engineers Cannelton Dam through bulb turbines to generate an average gross annual output of about 458 million kilowatt-hours (kWh). The site will include an intake approach channel, a reinforced concrete powerhouse and a tailrace channel. The powerhouse will house three horizontal 28-MW bulb-type turbine and generating units with an estimated total rated capacity of 84 MW at a gross head of 25 feet." Hydroelectric plants are often operational for at least 80 to 100 years. AMP was founded in 1971, according to its website, "when a group of municipally-owned electric systems joined forces to lower costs and increase the reliability of their power supply to benefit their consumer-owners."