|Cofferdam construction at Cannelton was completed by Kiewit Traylor Construction in June. All photos courtesy AMP.|
By Lindsay Morris, Associate Editor
While renewable energy advocates have been pushing for solar and wind over the last few years, American Municipal Power Inc. (AMP), based in Columbus, Ohio, has chosen hydropower as its paramount renewable. AMP, a nonprofit electric cooperative, is moving forward with four developments along the Ohio River that will total more than 300 MW of generation for its member communities.
|AMP CEO Marc Gerken said that hydropower been “largely ignored” in recent discussions about alternative energy. “Hydro is not a new, shiny, sexy technology,” he said. “But it doesn’t have to be.”|
|Marc Gerken, CEO of AMP.|
It’s true, hydropower is not new. Hydroelectric generation comprised approximately 40 percent of generation in the early 1900s, but that was over a century ago. In 2011, hydroelectricity accounted for 7 percent of all generation, according to the National Hydropower Association (NHA).
But hydropower is anything but tapped out. About 130,000 sites in the U.S. could be used to produce another 30,000 MW of hydropower, according to the Department of Energy (DOE). A study by the Electric Power Research Institute found at least 23,000 MW of additional capacity, including hydrokinetic and wave energy that could be brought on line by 2025. Under a best-case scenario, the study estimated possible maximum development of 95,000 MW.
Gerken said AMP and its partners turned to hydroelectric partially because of how reliable the resource is. “I know what I’m going to get out of these units tomorrow. I can’t do that with wind or solar.”
Currently, 67 percent of domestic renewable generation comes from hydropower, according to NHA. In recent years, environmental groups have criticized hydro projects that require the construction of new dams. But all of AMP’s hydro projects are being sited on existing U.S. Army Corps of Engineers locks and dams. In fact, the Corps’ original intention was for run-of-river projects to be installed at the dams where AMP is now building, Gerken said.
AMP’s run of river approach—generating power from the natural flow and elevation of a river without a large impoundment of water—achieves capacity factors of 55 to 60 percent. That percent is high in comparison to other renewable forms of energy. Wind in the Midwest has a capacity factor in the 20 to 30 percent range. And the capacity factor of solar is in the 15 to 18 percent range, Gerken said.
In 2006, AMP commissioned a study by MWH of 10 undeveloped projects along the Ohio River. Based on the results of the study, AMP sought and gained licenses from the Federal Energy Regulatory Commission for three projects: Cannelton Locks and Dam, Smithland Locks and Dam and Willow Island Locks and Dam. AMP also has a co-license with its partner community of Hamilton, Ky. for a fourth project at Captain Anthony Meldahl Locks and Dam.
These four are not the first of AMP’s hydro developments. AMP commissioned its first hydro project along the Ohio River in 1999: the 42-MW Belleville hydro plant. Since that time, AMP has completed two other member-owned hydro plants along the Ohio River at Greenup and Hannibal.
All four projects currently under construction are expected to be completed in 2014 or 2015.
The 84-MW Cannelton project, located in Hawesville, Ky., was the first of the four projects to break ground on Aug. 5, 2009. Project costs are projected at $416 million. Cannelton is expected to be the first project finished, with completion aimed at spring of 2014.
The Cannelton project will divert water from the existing Cannelton Locks and Dam through bulb turbines to generate an average gross annual output of approximately 458 million kilowatt-hours. The site will include an intake approach channel, a reinforced concrete powerhouse and a tailrace channel. The powerhouse will house three horizontal 29.3-MW bulb type turbine and generating units at a gross head of 25 feet. A 1,000-ft-long 138-kV transmission line interconnection is planned to connect to MISO.
Kiewit Traylor Construction was awarded the contract for the design-build cofferdam and excavation, which was completed in June of 2010. Walsh Construction Group was awarded a $192 million contract for the general construction of the powerhouse and appurtenances. The Walsh contract also includes the construction of the three-unit bulb turbine type powerhouse adjacent to the existing Cannelton Locks and Dam. Walsh has mobilized to the site, completed erecting its batch plant for concrete operations and placed over 1,000 yards of the nearly 100,000 yards of concrete needed for the plant. Walsh has also continued with pre-erection of the mechanical equipment for the plant.
Other contracts have been awarded to MWH (design and engineering services), Mueser Rutledge Consulting Engineers (civil engineering services), Oregon Iron Works (gates and trashrack equipment), Iljin/Pan American Supply (main power transformers), Morgan Engineering (crane equipment) and Vectren (transmission interconnection within the powerhouse).
Voith Hydro is supplying turbines and generators for Cannelton as well as the three other run-of-river facilities under a $420 million contract.
The 72 MW Smithland project in Smithland, Ky. will divert water from the existing Smithland Locks and Dam through bulb turbines to generate an average gross annual output of approximately 379 million kWh. The site will include an intake approach channel, a reinforced concrete powerhouse and a tailrace channel. The powerhouse will house three horizontal 25.3 MW bulb type turbine and generating units at a gross head of 22 feet. A two-mile-long 161-kV transmission line interconnection is planned to connect to MISO.
|Smithland project cofferdam after the river returned to its normal level.|
The Smithland project experienced some construction delays in May 2011 when continuous rains and backwater effect from the Mississippi River caused the flood forecast and the rate of rise to near the crest of the cofferdam. Elevation at that part of the river had not reached such levels since 1937. The floodway structure in the cofferdam is used to channel the flow of the river into the dam and allow flooding to occur in a controlled manner. This helps prevent serious damage to the structure of the cofferdam during significant events.
Due to high water on the Ohio River, the U.S. Army Corps of Engineers directed AMP to flood the cofferdam on May 2. Fortunately, not much damage was caused to the structure itself or the side walls, or slopes, Gerken said. However, the flooding caused construction to fall behind by 40 to 50 days.
|Smithland project cofferdam construction slowed in May due to high water. Here the river level is at a high.|
Despite the flooding, the cofferdam was expected to be completed in October 2011. A design-build construction and excavation contract for the cofferdam is in place with CJ Mahan Construction. The Smithland project is expected to be completed in early 2015.
Located in Pleasants County, W. Va., the 35 MW Willow Island Project started construction in June 2011. The project will divert water from the existing Willow Island Locks and Dam through bulb turbines and generate an average annual output of approximately 239 million kWh. The site will include an intake approach channel, a reinforced concrete powerhouse and a tailrace channel. The powerhouse will house two horizontal 22 MW bulb-type turbine and generating units at a gross head of 20 feet. A 1.6-mile-long 138 kV transmission line interconnection is planned to connect to PJM.
Ruhlin Construction Co., through its subcontractor, Mueser Rutledge, is designing the cofferdam. The powerhouse contractor has not yet been chosen. The Willow Island project is scheduled to be completed in the spring of 2015.
Largest of the four projects, the Captain Anthony Meldahl project, will have a capacity of 105 MW once completed in the summer of 2014. The project began construction in April 2010.
The project will divert water from the existing Captain Anthony Meldahl Locks and Dam through bulb turbines and generate an average annual output of approximately 239 million kWh. The powerhouse will house three horizontal 35 MW bulb type turbines at a gross head of 30 feet. If interconnected to MISO, an eight-mile-long 138 kV transmission line planned. If interconnected to PJM, a five-mile-long 345 kV transmission line is planned.
The $473 million facility is located near Hamilton, Ohio. A contract is being completed with the AMP member community of Hamilton, meaning the city will maintain 51 percent ownership of the project.
Angelo Iafrate Construction has been chosen as the contractor for the Meldahl cofferdam. Alberici/Baker was awarded the contract for the powerhouse.
Beyond the Quad
In addition to the four projects that already have permits, AMP and its member community Wadsworth, Ohio are also pursuing the development license for a 48 MW project at the Robert C. Byrd Locks and Dam on the Ohio River. A sixth Ohio River development is proposed at Pike Island with AMP member community Oberlin, near Cleveland.
Gerken said these two projects will trail behind the other four by about three years. “We need to go through more permitting and licensing.”
Many developers have avoided investing in hydroelectric generation in the past due delays in permitting and high capital investment. Gerken said that despite the delays, hydropower is worth installing because it is a zero carbon footprint alternative with inherent reliability. On average, a hydroelectric project costs about the same per kilowatt hour as a nuclear project, but entails less construction risk and no fuel costs, Gerken said.
But will hydropower be used to fill some of the generation gap that is expected as a result of coal-fired retirements in coming years? Over the short term, Gerken said he predicts natural gas generation will be used to fill the gap. Run-of-river hydropower, however, could play more of a role in terms of long-term generation.
“If the environment became such that we had clear regulations that provided adequate time to capture and recover costs, I think hydro would be far superior to coal or even nuclear.”
For the near future, hydropower will likely continue to take a back seat to other forms of generation. But for AMP and its member communities, it will take center stage on the Ohio River.
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