If anyone is going to get hydro power out of Falls Lake Dam, it’s going to be the City of Raleigh. And if Raleigh can’t do it, they don’t want anyone else to, either.
City officials are researching the feasibility of installing a hydroelectric facility in the Falls Lake Dam. Similar to a project at Jordan Lake, turbines installed at the intake tower would be powered by the flow of water through the dam, generating electricity.
The city would either sell the power to a utility company, such as Progress Energy, or use it to offset the power needs of one of its own facilities, like the sewage treatment plant.
If built, the facility would generate enough electricity to power about 350 homes.
The dam is owned and operated by the Army Corps of Engineers. Ken Waldroup, the city’s assistant director if public utilities, said the city would not interfere with the normal operations of the dam and that generating power would not be a top priority.
Setting Priorities
Falls Lake provides the city residents with about 67 million gallons of water a day, so city officials have a vested interest in making sure the supply isn’t compromised.
Waldroup explained that if there is a higher level of water than necessary to meet water supply and quality standards, the Corps can opt to release that water quickly over the course of a few days or more slowly. By releasing the water more slowly, there is more water available in case of drought.
Because the top priority is water supply, the city would be perfectly fine with keeping an emergency reserve. But, city staff said they don’t believe that a private company would have water supply in mind.
The city is concerned that a private company might try to pressure the Corps to release that extra water more quickly, spinning the turbines faster and resulting in higher profits.
“Personally, I don’t think it’s a concern,” said Thomas Freeman, the operations project manager at the dam. “We’re not Congressionally authorized to discharge water for hydro power. It’s whatever is available to turn those turbines—that’s what you get.”
For the city, the best case scenario would be that it could build a hydroelectric facility and reap the financial and environmental benefits that would result from a renewable energy source.
But Waldroup said if the project couldn’t be built and it kept a private entity from building its own facility, that would be a good result, too.
The Dam Background
The Falls Lake Dam has five Congressionally-regulated uses: fish and wildlife, recreation, water supply, water quality and flood damage reduction.
The Corps regulates the flow of water though the dam according to these priorities, none of which include hydro power.
About 42 percent of the water behind the dam is allocated for Raleigh’s drinking water, while about 58 percent keeps the Neuse River flowing properly.
The city became interested in hydro power back in 2009 when Community Hydro LLC, a private power company, filed an application with the Federal Energy Regulatory Commission, or FERC, to research the possibility of a hydroelectric facility.
While the Corps owns and operates the dam, FERC is the governing body that would give the OK to install the project.
This threw up a red flag for the city. Waldroup said city officials were highly opposed to having a private company anywhere near the city’s water.
In October 2009, the city filed a competing application, which was approved by FERC in November 2010.
The city is now is working through the licensing process, which includes meeting with stakeholder groups and the community, and preparing draft engineering plans. The draft feasibility report is expected to be completed in July.
The final license application would be submitted to FERC in November 2013. If given the green light, construction would begin in 2017 and could be completed about a year later.
The city has already shelled out $140,000 for the first phase of the application process and is looking to spend about $235,000 for the second phase, which will include everything up to that final license application. If the project is deemed unfeasible at any point along the way, the research costs stop there.
If approved, the total cost of the project, from start to finish, will be between $7 million and $10 million. The funding for the project would come from increased water and sewer rates, along with federal and state grants for renewable energy projects.
Electric Eels?
Since the flow of the water leaving the dam has a direct impact on the fish that call the Neuse River home, how that flow is changed for hydro power could be a concern for fish lovers.
Joseph Hightower, a biologist for the U.S. Geological Survey and professor at North Carolina State University, said that from a fish’s perspective, changing the flow of the water could limit its ability to move upstream.
But, Hightower said that if the dam is operated in the same way that it is today, which means taking fish migration into consideration, he doesn’t think there would be any adverse affects caused by the facility.
While the fish downstream may not see an impact, Waldroup said that fish passage through the facility wouldn’t be an option because of the cost. Adding fish passage through the dam would cost between $3 million and $5 million.
At a Jan. 23 public meeting, Fritz Rohde, a biologist at the National Oceanic and Atmospheric Administration, said there is evidence that eels are passing through the Milburnie Dam and making their way to Falls Lake.
“Based on that presence of eels, we are strongly considering prescribing fish passage for eels for this project,” he said.
“That’s OK,” Waldroup responded. “That would end the project.”
Waldroup explained that the city would respect the organization’s decision if fish passage was mandatory, so long as the same request would be made for any other entity that was interested in building its own facility.
He went on to say that he believed that the renewable energy garnered from the project would be a benefit to the environment and those net benefits should be taken into consideration when the organization is crafting its recommendation.
Safety Rating
Currently, the Falls Lake Dam’s Dam Safety Action Classification, or DSAC (pronounced Dee- Sac) stands at a 3.
Thomas Freeman, the dam’s operations project manager, explained that the DSAC ranges from 1 to 5, with 1 being completely unsafe and 5 being so safe it can only be found in a fairy tale. Falls Lake’s DSAC rating is not because of its structural integrity, but because of the communities that line the river, like Smithfield and Goldsboro.
If there was a complete failure of the dam, Freeman said, there could be a significant loss of life and property.
Freeman said about five years ago the Corps studied various scenarios for dam failure, including operator error, terrorism and natural disaster, and “the widest array of things that could go bad and if it goes bad, what it would take to fix it.”
Back when they did the evaluation, the hydro power conversation wasn’t happening, so it was not considered as part of that study. The Corps is now speaking with FERC about that process and its findings.
“I’m not inferring that a hydro power [facility] would affect the safety one way or another, but it’s something to look at,” Freeman said. “We’re going to make sure that we don’t take anything for granted.”
Once the city comes up with a conceptual design for the project, the Corps will study the potential failure modes of the project.
Waldroup said the city will complete a thorough review to make sure that the project would not decrease the dam’s safety rating.
“It is our hope that the design we’re proposing would not in any form add to or otherwise contribute to unsafe conditions that might currently exist as defined by this act,” he said.
