Greater hydro potential at non-power dams?
Letter to the Editor:
After reading the article “Stimulating New Hydro in the U.S.,” in the Hydro Review 2008 Industry Sourcebook (pages 10-16), I offer the following comments concerning power at non-power dams:
The article states that the energy potential at non-power dams is “about 5,000 MW, … which is only 30 percent of the total potential that could be developed within the next 20 years.” The article also states that, with favorable economic conditions, such as full production tax credits (PTCs) and renewable portfolio standard (RPS) credits comparable to those offered for wind and solar projects, this figure could range as high as 10,000 MW.
However, previous figures and studies I have seen indicate a much larger energy potential for generation at existing dams. For example:
1) EPRI Bulletin BR-112038, published in 1999, states, in reference to hydropower, that “…nearly 20,300 MW of new capacity could be developed without building new dams.” (from page 11);
2) A U.S. Department of Energy Interagency Hydropower Resource Assessment Team, established in 2000 to determine the country’s “true” hydropower potential, arrived at a conservative figure of 30,000 MW for both new hydro schemes and installation of hydropower at existing dams. The team included representatives from the U.S. Department of the Interior’s Bureau of Reclamation, the U.S. Army Corps of Engineers, the Bonneville Power Administration, the Federal Energy Regulatory Commission, the Alaska Power Administration, Oak Ridge National Laboratory, and the Idaho National Engineering and Environmental Laboratory. This study assessed environmental, legal, and institutional constraints related to developing both new and existing dams for generation. The study assessed 2,527 existing dam sites without power generation and 2,761 undeveloped sites, which implies that the amount of generation is about equally split.
3) The Hydro Review article “Renewable Energy in the U.S.: Achieving 25% by 2025?” (August 2007, pages 12-16) states that, according to a National Hydropower Association (NHA) report, “…23,000 MW of identified potential can be developed immediately with no new dams … NHA says that with the right policy support the 23,000 MW of potential could more than double.”
I think the larger numbers cited above have been around longer, and appear to have input from more agencies and sources. They probably represent the total possible generation value at non-power dams, not necessarily the “economically” viable number based upon present PTCs and RPSs. As we all know, tax credits are quite variable dependent upon the need for “renewable” energy sources; consequently, the “economically” feasible generation number can be quite variable.
In summary, I believe the “feasible” numbers of 20,300 MW, or 23,000 MW (and I prefer the latter) should be used to identify the potential for power generation at non-power dams. If you start downsizing the “possible” generation at non-power dams, you enter into an economic morass of RPS/PTC credits which change frequently and can thereby increase or decrease the number of megawatts that can be developed. The fact that you could reasonably develop 23,000 MW of electrical power without building new dams versus 5,000 MW is a significant consideration when discussing government assistance to develop these projects. The larger number (23,000 MW) would eliminate the construction of 23 nuclear power plants or 23,000 wind generators, and is a very strong argument for the development of hydroelectric power at existing dam sites.
– David M. Clemen, Senior Electrical Engineer (Retired)
Contractor hired to rebuild Missouri’s 408-MW Taum Sauk
Missouri utility AmerenUE hired joint venture Ozark Constructors LLC to rebuild the breached upper reservoir of the 408-MW Taum Sauk pumped- storage project.
Taum Sauk has not operated since the reservoir’s ring dam breached Dec. 14, 2005, releasing 1.4 billion gallons of water down the Black River, injuring nine people, and damaging property.
AmerenUE said Ozark Constructors is a joint venture of Colorado-based heavy civil contractor ASI Constructors Inc. and St. Louis-based Fred Weber Inc., which works in mining, aggregate processing, and heavy civil construction.
The utility said it also selected Paul Rizzo Associates Inc. as engineer of record and project manager. Rizzo designed a roller-compacted-concrete replacement dam approved by the Federal Energy Regulatory Commission.
AmerenUE expects the plant to remain out of service through at least the fall of 2009. It said insurance should cover substantially all of the cost to rebuild the project.
The reservoir was overtopped when pumps failed to shut off. Once overtopping began, erosion undercut the rockfill dam and soon formed a breach about 656 feet wide at the top of the dam and 496 feet at the base. The reservoir was emptied within 25 minutes.
A Missouri Public Service Commission staff report blamed utility management for the failure.
Alstom Hydro to modernize 48-MW Lake Chelan
Chelan County Public Utility District (PUD) awarded a $29.7 million contract to Alstom Hydro U.S. Inc. to design, manufacture, and install two turbines, two generators, and governors for a hydro modernization project at 48-MW Lake Chelan in Washington.
The project involves replacement of equipment that has been in operation since 1928. Design began immediately after the contract was signed. A model test of a new unit is scheduled for fall 2008 to evaluate improved efficiency.
Following analysis of the test results, installation is scheduled to start in spring 2009. Each unit is expected to take a year to install, the district said.
Chelan County PUD said it initiated negotiation with Alstom Hydro U.S., Littleton, Colo., and a second company after it received no bids in response to a 2006 solicitation. The contract price is capped at $29,647,170.
The Lake Chelan project includes a 55-mile-long natural glacial lake that was raised 21 feet by construction of a 40-foot-tall dam; a 14-foot-diameter, 2.2-mile power tunnel; a powerhouse containing two vertical Francis turbine- generators; and a tailrace adjacent to the confluence of the Chelan and Columbia rivers.
Financing plans in place for Ohio River projects
American Municipal Power-Ohio reports it secured financing to construct the 72-MW Smithland and 84-MW Cannelton hydroelectric projects, both on the Ohio River in Kentucky.
AMP-Ohio informed the Federal Energy Regulatory Commission (FERC) it has access to a $150 million revolving line of credit for each project with a syndicate of bankers led by JP Morgan Chase Bank. The line of credit can be increased to $250 million for each project at any time before terms expire in December 2010, it said.
AMP-Ohio also reported it secured Clean Renewable Energy Bonds totaling $2.1 million for the Smithland project, and a commitment of $1 million from its members for the development phase of that project.
As for Cannelton, AMP-Ohio reported it was in the process of securing Clean Renewable Energy Bond funding for the project. It already had a commitment of $1 million from its members for the development phase of the project.
Licenses for both projects required that financing plans be filed with FERC 90 days prior to the start of land clearing activities. The licenses also stipulated financing plans must be approved before the licensee could begin civil works construction, or ground-disturbing activities, other than those required for subsurface site exploration.
AMP-Ohio represents 119 municipal utilities in five states. MWH, the owner’s engineer, is providing engineering design services for both projects.
Pennsylvania awards grant to develop 2.6-MW Beltzville
The state of Pennsylvania awarded a $750,000 grant to the borough of Leighton to support development of a 2.6-MW hydroelectric project at Beltzville Dam.
The Beltzville project would be built at a 175-foot-tall U.S. Army Corps of Engineers dam on Pohopoco Creek in Leighton. It would feature a powerhouse with a 1.7-MW unit and a 900-kW unit. The project would be expected annually to produce nearly 9,500 megawatt-hours and offset 9,600 tons of carbon dioxide.
The borough submitted an application to the Federal Energy Regulatory Commission (FERC) in December 2006, seeking an original license to build and operate the project. In August 2007, FERC issued notice that it had accepted the application.
The Beltzville project grant is one of 24 Pennsylvania Energy Development Authority (PEDA) grants totaling $11.2 million announced in October 2007. In releasing names of the recipients, Gov. Edward Rendell said the grants would attract nearly $122 million in new private economic growth.
Applicants for PEDA financing can seek grant assistance for capital costs for a variety of energy projects, including “low-impact” hydropower.
Colorado town endorses 1.05-MW Castle Creek project
Aspen voters approved two ballot questions supporting redevelopment of a small hydroelectric project on Castle Creek that has been idle for nearly half a century.
The 1.05-MW Castle Creek project would use existing water rights, headgates, and water storage components of the original Castle Creek hydroelectric plant, which met all of Aspen’s electricity needs from 1892 through 1958. Restoring generating capacity will require construction of a new powerhouse and a penstock from a water plant to the powerhouse, installation of two turbines and generators, and related electric system work.
In a November 2007 election, a referendum passed 576-228 that allows the city to issue general obligation bonds for building and equipping the new hydro plant. The measure allows the city to increase its debt by up to $5.5 million, with a maximum repayment cost of $10.78 million by the issuance of general obligation bonds.
The expected $5.1 million improvement cost is to be partially financed through appropriations of $780,000, and through a grant of $400,000, leaving $3.92 million to be financed through bond sales. Assuming a 20-year amortization period, the expected capital cost of the facility would be offset by savings in power now purchased from the Municipal Energy Agency of Nebraska.
Voters also approved, 616-182, a referendum authorizing the city to change the use of property at the proposed site to allow for building the power plant.
Switching from mostly coal-fired energy purchases from the Municipal Energy Agency of Nebraska to the production of power at the proposed hydroelectric project would eliminate an estimated 5,167 tons of carbon dioxide emissions annually, Public Works Director Phil Overeynder said.
The new facility would increase electricity production by 5,500 megawatt-hours annually. It also would increase the city electric utility’s renewable energy supplies by 8 percent.
On-line report: 7.6-MW Gross Reservoir
Denver Water reports its new 7.598-MW Gross Reservoir hydroelectric project, on South Boulder Creek in Boulder County, Colo., is expected to generate 25,000 megawatt-hours of electricity each year.
Denver’s Board of Water Commissioners holds the Federal Energy Regulatory Commission (FERC) license for the project, which entered full operation in August 2007.
The new plant uses water impounded by a 340-foot-tall, 1,050-foot-long concrete gravity arch dam built in 1954. The dam forms Gross Reservoir, which stores 41,000 acre-feet of water and is a major component of Denver’s municipal water supply system.
Releases from the reservoir are made through low-level outlet works consisting of an intake slide gate, a tunnel, conduits, and a valve house. To supply water to the new powerhouse, which is about 400 feet downstream of the valve house, Denver Water installed a 66-inch-diameter penstock.
The original FERC license for the dam and reservoir, issued in 1951, included a provision for an 8-MW hydropower plant. Denver Water initially chose not to build the power plant, concluding that generating electricity would not be economical due to a scarcity of water in the region.
However, in seeking a relicense for the project in 2001, it revisited the potential for hydroelectric power at the site. Denver Water negotiated a 20-year power purchase agreement with Xcel Energy and redesigned the penstock configuration to make civil construction less expensive.
In 2004, FERC amended the license to include authorization for the hydroelectric plant. The powerhouse features two horizontal Francis turbines manufactured by Alstom Canada, designed for a rated output of 3.799 MW each, and synchronous generators manufactured by General Electric, rated at 4,500 kVa, and associated mechanical and electrical equipment.
Denver Water designed the project and managed construction. Construction costs totaled $14.1 million and included a $10.6 million contract to Western Summit Constructors Inc. of Denver, general contractor.
Corps cites multiple factors in 100-MW Detroit Dam fire
The U.S. Army Corps of Engineers reports inadequate components, apparent gaps in a protective relay system, and operator error contributed to fire damage at the 100-MW Detroit Dam powerhouse on Oregon’s North Santiam River.
The Corps previously determined the cause of the electrical fire to be phase-to-phase arcing in Unit 2 bus works, ancillary equipment used for the electrical connection from the generator to the step-up transformer.
A Corps board investigating the June 19, 2007, fire added that a contractor installed surge arrestors different than those approved and used under-rated cable. The Corps’ quality control and quality assurance process did not discover the situation before the fire.
Additionally, there was no ability to trip equipment quickly. The power to a critical protective relay was tagged out, removing a level of protection. There also appeared to be gaps in the plant relay protection system, the board said. Drawings were inaccurate and could have contributed to confusion and a lack of understanding.
As for operator error, a breaker was closed manually without proper diagnosis of a problem, the board said.
Corps estimates repairs could total $9 million
At one time, the Corps estimated costs to replace damaged equipment could total more than $4 million. However, the Corps now says estimates for returning the project to service, including clean up, interim repairs, and capital improvements to switchgear, range from $7 million to $9 million.
In-house Corps teams made interim repairs. The Corps said contractors named to return the project to service include Shaw Inc., for clean up, and National Electric Coil, which is to rewind Unit 2. The government also awarded a contract to Olssen Electric to perform reliability upgrades.
The Corps said it planned to return Unit 1 to service in February 2008. Unit 2 will be returned to service sometime during summer 2008, after the rewind.
Corps returns 20-MW Big Cliff to service
The Corps returned the 20-MW Big Cliff powerhouse to service in mid- September 2007 on the North Santiam about 3 miles downstream from the Detroit powerhouse.
Although Big Cliff was not damaged in the fire, its systems are connected to the Detroit powerhouse, which in turn is connected to a Bonneville Power Administration substation.
Alcoa wins additional power from two Washington projects
Hydro operator Chelan County Public Utility District (PUD) approved a 17-year power sales agreement with Alcoa, increasing the previous supply of hydropower and enabling the aluminum company to open a third potline at the Alcoa Wenatchee Smelter.
The agreement, approved in December 2007, secures about 267 MW for Alcoa from the 1,236.6-MW Rocky Reach and 623.2-MW Rock Island hydroelectric projects on the Columbia River in Washington.
Alcoa said that increase of about 84 MW over its current contract will enable it to expand production, add about 60 jobs, and assure the smelter’s long-term survival.
The agreement is to take effect Nov. 1, 2011, when the current contract expires, and run through October 2028. The deal will provide Alcoa about 25 percent of the renewable hydropower produced by the two projects.
The additional power will enable Alcoa to increase production by 42,000 metric tons per year to a total 142,000 metric tons annually.
Chelan has another large supply contract with Puget Sound Energy, providing the utility another 25 percent of the power from Rocky Reach and Rock Island. The PUD has been seeking Clean Renewable Energy Bonds, under the Energy Policy Act of 2005, to finance modernization of Rocky Reach, Rock Island, and its other hydro facilities.
NYPA reaches refurbishment milestone at St. Lawrence-FDR
The New York Power Authority (NYPA) has passed the halfway point in a $281 million, 16-unit life extension and modernization program at its 912-MW St. Lawrence-Franklin D. Roosevelt Power Project.
NYPA returned the ninth turbine-generator to service on Oct. 31, 2007. Work on the refurbished unit included replacement of an Allis Chalmers turbine with a new turbine. NYPA previously overhauled eight turbine-generators, each of those with turbines originally manufactured by Baldwin Lima Hamilton, the other company that provided turbines to the project.