Unlocking hydro potential

20 August 2012

Hydropower still has enormous unfulfilled potential in the US. Recent reports suggest that the country’s conventional hydro fleet could be expanded by 15% - without the construction of a single new dam. But can hydro find the right key to unlock such growth potential? Although the Department of Energy has been applauded for its research efforts into energising non-powered dams, the US Army Corps of Engineers has also been criticised for excluding hydro from recent proposals. Suzanne Pritchard reports.

“It is yet another demonstration that our country’s existing infrastructure holds tremendous potential for expanded hydropower production,” Linda Church Ciocci, Executive Director of the US’ national-hydropower-association (nha), said in response to a recent Department of Energy (DOE) report. Entitled An Assessment of Energy Potential at Non-Powered Dams in the US, the report estimates that 12GW of hydropower potential exists at over 54,000 non-powered dams across the states.

“DOE’s new study clearly shows the tremendous potential for growth in America’s hydropower industry, without the need to build a single new dam,” Church Ciocci said. “By adding power stations to existing dam infrastructure we can provide clean, affordable power to 3.9M more American homes.”

Carried out under the auspices of the DOE’s Wind and Water Power Programme, research for the report was undertaken by the Oak Ridge National Laboratory, along with input from the Idaho National Laboratory. Together the two labs quantified the potential capacity and generation available from adding power production capability to non-powered dams in the US.

Approximately 2500 dams currently provide 78GW of conventional and 22GW of pumped storage hydropower across the country. However, the US also has more than 80,000 non-powered dams (NPDs) that do not produce electricity but perform other functions such as water supply and inland navigation. But why are these dams now considered to be highly attractive for expanding renewable energy supply?

“Importantly,” the DOE report states, “many of the monetary costs and environmental impacts of dam construction have already been incurred at NPDs, so adding power to the existing dam structure can often be achieved at lower cost, with less risk, and in a shorter time frame than development requiring new dam construction.” Indeed it is the abundance, cost, and environmental favourability of NPDs, combined with hydropower’s reliable and predictable nature, which makes these dams so attractive.

Of more than 80,000 NPDs found across the US, 54,391 were analysed for the DOE report which was published in April 2012. Average monthly flows for these structures ranged from 0.03m3/sec to 1940m3/sec. Dams which were eliminated from consideration either had erroneous geographic information or erroneous flow or drainage area attributes that could not be resolved and corrected through independent investigation of maps and records. However, the report suggests that these dams are likely to be relatively small or have low hydro potential. With this in mind dams less than 1.5m in height were also excluded from analysis. To ensure that the remaining dams were analysed and characterised as accurately as possible a thorough quality control and review process was carried out.

Preliminary hydropower potential for the 54,000 NPDs only considers approximations of site characteristics (eg dam height) and hydrologic variability. Electric generating capabilities were calculated using the assumption that all water passing a facility would be available for conversion into power and that the hydraulic head would remain constant. Further assessment of site feasibility, environmental impact and economic benefit was not taken into account.

Therefore, the report states, at this current phase of assessment the total potential capacity and annual generation is estimated to be 12GW and 45TWh/yr. This is around 15% of the existing US conventional hydropower total. It must also be borne in mind that current economic limitations on project size will produce designs with less capacity then indicated in the research.

Although thousands of NPDs were assessed in this study most of the energy potential is found in a relatively small subset of dams. The top 597 NPD sites, each with a potential capacity greater than 1MW, contribute nearly 90% of the estimated additional national capacity from NPDs. Furthermore, 40% of the national total is from the top 25 NPD sites only, while the top ten sites alone could add up to 3GW of new hydropower.

According to the DOE report most of the potential sites are found in the northeastern US, Ohio river basin and upper and lower Mississippi river basins. High potential was also found for many US Army Corp of Engineers’ locks and dams (87 sites with a total potential of 6.9GW). The interesting point here is that as locks and dams were built mainly for navigation purposes instead of municipal water supply and irrigation, there may be less concern about impacts regarding other competing water usage. Approximately 260MW of additional capacity could also be gained from US Bureau of Reclamation NPDs. Indeed the bureau is carrying out its own detailed evaluation into this (see shaded panel).

Other interesting points highlighted by the DOE study are that new NPD development can help diversify the spatial distribution of national hydropower investment. As although hydro is already a significant source of electricity in the Pacific Northwest and California regions, the best potential for new development at NPDs is at locations with less existing hydropower usage. Furthermore, the DOE states that by overlaying the potential NPD sites with National Renewable Energy Laboratory estimates of wind and solar power potential, ‘it can be seen how the development of hydropower at NPDs may complement the development of other renewable technologies and augment the national portfolio’.

DOE acknowledges that further refinement of the research methodology used in this report will be of future benefit. For example refined site development models, along with enhanced modelling of water availability through collaboration with US Geological Survey research efforts, would provide more robust estimates. However, this current assessment does still provide very useful preliminary information for stakeholders (such as developers, municipal planners and policy makers) who can evaluate the potential to increase hydropower production at NPD sites. Further detailed studies of site specific costs and impacts will obviously be required by potential developers.

“It is crucial that we now work together to unlock hydropower’s potential for growth,” Linda Church Ciocci from the NHA said. “The industry stands ready to work with all related federal agencies to maximise the potential at these sites. Doing so will bring more affordable, reliable and sustainable electricity to America’s households and businesses, and expand economic opportunity for supply chain companies across the country.”

Supply chain snapshot

It was with the hydro supply chain in mind that the NHA released the first-ever US Hydropower Supply Chain Snapshot in April 2012. Described as an interactive online map, it shows the breadth and diversity of the industry’s supply chain across the country, including regions not traditionally associated with renewable energy. Based on a representative sampling of the NHA’s membership, the snapshot allows users to search nearly 2000 companies such as:

• Project developers.

• Construction companies.

• Architecture and engineering firms.

• Electricians, biologists and manufacturers that supply the hydropower industry.

Users can view companies’ locations state-by-state, and each map point links to the company’s website, providing a clear sense of the businesses and products connected to the industry.

“The US Hydropower Supply Chain Snapshot shows a vibrant industry that benefits communities around the country,” Church Ciocci said. “And it is supporting jobs in a wide range of businesses from coast to coast.”

Of the 1924 companies included in the Snapshot’s map 415 are based in the south, 544 in the west, 505 in the Midwest and 460 are in the northeast.

The rust belt states of Illinois, Indiana, Michigan, Ohio and Pennsylvania alone account for 583 of the Snapshot’s companies, demonstrating hydro’s role in supporting traditional US manufacturing states.

Weschler Instruments is a Cleveland, Ohio-based manufacturer and distributor of power and process instrumentation, and is one of the hydro supply chain companies included in the Snapshot. The company has been headquartered in Cleveland since its founding in 1941 and currently sells products to the hydro industry worldwide.

“Weschler Instruments has been involved with the hydro industry for many years, and we offer specialised products tailored to the needs of hydro facilities,” said Gerald Lucak, the company’s Vice President. “Weschler's digital instrumentation is used in new facilities and plant upgrades to help hydro providers increase their power output and improve efficiencies. We’re glad to be a part of the Snapshot, and we hope it helps people see just how significant a role hydropower plays for local manufacturing firms like ours.”

The Snapshot also helps dispel preconceptions about the hydro industry, according to Carol Goolsby, Vice President of Duke Energy’s regulated hydro fleet. “Some don’t immediately think of the south as home to renewable energy,” she said, “but the hydropower Snapshot clearly dispels that myth.

“Duke Energy has a significant hydroelectric portfolio in the south, including capacity increases to our Jocassee and Bridgewater hydropower stations last year. We are supported by a strong network of southern manufacturers, mechanical and electrical contractors, and other small local businesses. We’re pleased that the Snapshot can tell the story of our regional hydro industry so clearly.”

Tax credits

The success of regional industry players has also helped to stimulate significant hydro growth nationwide over the past decade. In 2010, hydropower accounted for 65.9% of the US’s renewable electricity generation and 7% of total electricity generation, according to the US Energy Information Administration. Areas of development and growth included the modernisation of existing facilities, converting non-powered dams, and the deployment of hydrokinetic and conduit technologies.

Such development has also been supported by targeted federal policies like the federal Production Tax Credit (PTC), which has provided certainty to the industry and helped accelerate investment and project development. Unfortunately the hydropower PTC is set to expire at the end of 2013 but the NHA is currently working hard to extend this. However, the expiration date is already creating uncertainty among hydro investors and developers, who are beginning to reduce or cancel planned construction.

“The Snapshot puts a face on the companies and communities that will likely be hurt if the Production Tax Credit is not extended this year,” said Church Ciocci. “That’s true in the southeastern US, where hundreds of hydro supply chain companies are based, just as it is in the Rust Belt and the Pacific Northwest. All of these companies rely on the long-term certainty provided by the PTC.”

Disappointing news

Looking to the long term the NHA has also expressed its disappointment with a draft request for proposal (RFP) issued by the US Army Corps of Engineers in February 2012. Called Large Scale Renewable Energy Production for Federal Installations, the RFP calls for US$7B in shared capacity contracts to procure reliable, locally generated, renewable and alternative energy through power purchase agreements or other contractual equivalents. The energy would be purchased over a period of 30 years or less from renewable plants that are constructed and operated by contractors using private sector financing.

“This could potentially be the largest contract ever awarded by Huntsville Centre,” said Col Nello Tortora, commander of the US Army Engineering and Support Centre at Huntsville. “Under this contract, we will be buying energy produced, rather than the equipment to produce it. It will complement the suite of contracts we currently have that allow us to award energy projects and will go a long way towards helping the army meet its required energy reduction and energy security goals.”

“Huntsville Centre will award contracts to both large and small businesses according to four different renewable energy technologies: solar, wind, geothermal and biomass,” said Sarah Tierney, the project’s contracting specialist.

In submitting NHA’s comments on the draft RFP, Linda Church Ciocci stated: “The NHA is greatly disappointed that the draft RFP does not recognise hydropower (conventional hydropower, pumped storage and marine and hydrokinetic) as a renewable energy technology eligible to participate in the Large Scale Renewable Energy RFP. This is particularly surprising,’ she added, ‘considering that the US Army Corps of Engineers is the largest operator of renewable hydropower in the US, responsible for 24% of total US hydropower capacity.”

The NHA recommends that the draft RFP includes hydro as an eligibly technology. “This oversight sends the message to the hydropower industry, even if unintended, that the Department of Defence (DOD) is not interested in producing or procuring hydropower as part of its 25% renewable goal,” Church Ciocci said.

Church Ciocci continued further to add that hydro currently provides almost two-thirds of the US’ renewable electricity, serving as a base load renewable resource for decades to come. In addition pumped storage facilities currently provide regional and grid-scale energy storage and other ancillary services that are needed both for the integration of variable energy resources and for overall grid reliability. NHA cautions that that the need for these benefits will only grow in the future as the army seeks to increase its renewable energy portfolio and the uptake of variable energy resources, including wind and solar.

“Considering the size of the hydropower industry, its potential growth, reliability and flexibility, amending the draft RFP to include hydropower is warranted,” Church Ciocci re-iterated. “NHA believes that achieving the DOD’s renewable energy goal will lie in a holistic renewable energy approach, including the full suite of waterpower resources. This diversity is instrumental in providing the DOD and army with reliable, affordable and sustainable electricity. As such, we hope the final RFP is amended to include and encourage hydropower applications.”

No dates have as yet been set in relation to the RFP. As IWP&DC went to press the USACE was still processing industry input and was unable to give any comment. However, the Huntsville Centre said it will use industry feedback to develop the final version, which may vary from the original draft when issued.

Experienced veteran

Unparalleled commitment from industry members in helping to redress the balance for hydropower may well be one of the keys to unlocking hydro’s potential in the US. Newly elected NHA president and CEO David Moller is described as an experienced industry veteran keen on getting hydro’s powerful message out there.

Director of Power Generation for Pacific Gas and Electric Company, a Californian utility which operates the largest privately-owned hydropower system in the US, Moller has more than 35 years of industry experience. He has been involved in licensing, and the development and operation of hydropower projects ranging in size from 1MW to the 1212MW Helms pumped storage project.

“Last year we focused on getting out hydropower’s message as an essential tool in the clean energy toolbox – one that also helps integrate wind and solar into the grid and can provide large-scale energy storage,” said Moller. “This coming year is all about execution. Our country’s largest clean energy technology hydropower is poised for sustained, environmentally responsible growth.”

The NHA introduced its new officers and board members at the association’s annual conference in Washington, DC during April 2012. These also included:

• Vice President – Cherise Oram, Stoel Rives.

• Treasurer – Eric Van Duren, Mead & Hunt.

• Secretary – Suzanne Grassell, Chelan County Public Utility District.

“The incoming leadership team is composed of strategically-minded professionals with an ambitious vision for the association’s future,” said NHA Executive Director Linda Church Ciocci. “There is much to be done in the coming year to advance hydropower’s role as America’s premier clean energy technology. This talented group makes me certain of our continuing success.”

Tacoma Power's story: new hydro without new dams

Steve Fischer from Tacoma Power in Washington state, recently told delegates at the Northwest Hydroelectric Associationâ€â„¢s conference how the utility has developed its hydro capacity over the past 20 years. The following examples were achieved without the construction of any new dams.
â€Â¢ Hood Street hydro plant (1989): A 700kW Pelton turbine unit utilised hydro potential on a water supply pipeline.
â€Â¢ Wynoochee hydro plant (1994): Tacoma Power created the 12.4MW Wynoochee hydroelectric project by adding a hydroelectric facility to the US Army Corps of Engineers' Wynoochee river dam. The dam, located in the foothills of the Olympic Mountains in Grays Harbour County, was built in 1972 to provide flood control, industrial water storage and irrigation. It also supports the river's fishery. The scheme produces about 30GWh/yr, enough to serve 2100 northwest homes with power.
â€Â¢ LaGrande dam (2002): Prompted by the energy crisis in 2000, Tacoma Power installed a 432kW unit on an existing minimum flow release at LaGrande dam on the Nisqually river.
â€Â¢ North Fork Skokomish powerhouse (2012): New minimum flow release started in 2008 and, under a 2009 Cushman Settlement Agreement, approval was given for a new combined powerhouse/upstream fish collection system. FERC issued its approval in July 2010 and construction started in March 2011. Completion is scheduled for November 2012 with 2x1.8MW units set to generate 23.5GWh/yr.

USBR investigates hydro potential of conduits

In March 2011 the US Bureau of Reclamation (USBR) published a report called Hydropower Resource Assessment at Existing Reclamation Facilities. If all 191 identified sites with technical potential were developed, USBR estimated that approximately 268MW and 1.2MWh of energy could be produced annually. However, this did not take into account the hydropower potential of all its conduits. Further research was required and a phase two study (Site Inventory and Hydropower Energy assessment of Reclamation Owned Conduits) was published in March 2012. USBR worked with Idaho National Laboratory"™s Water Energy programme to produce the report.
Although USBR reserves the right to develop hydropower at its non-powered sites, the report hopes to aid irrigation districts, cities, municipalities, cooperatives and other non profit organisations in their decision making process to determine whether further analysis of a site"™s hydropower potential may be warranted.
Hydropower sites on conduits consist of elevation drops in canals, pipelines and tunnels where head can be captured to generate power; or at a turnout or siphon used to move water from a larger canal into laterals or smaller canals for delivery. Since USBR owns approximately 76,179km of canals, laterals, drains, pipelines and tunnels, many of them with little head or flow, it was determined that the first step was to create feasibility guidelines on hydropower potential. Based on discussions with low-head turbine manufacturers, hydropower developers, and USBR staff a reasonable minimum head for a technically feasible micro hydropower project was determined to be 1.5m. Additionally, it was determined that only sites with at least four months of operations per year that could produce 50kW of capacity based on gross head and the maximum flow capacity of the canal (design flow) would be identified in the report.
To locate and identify potential drops on these conduits, USBR staff researched project drawings, aerial imagery, utilised expertise from local area officials, and in some cases physically visited the canals. USBR and irrigation district personnel also provided seasonal, monthly or daily flow information when available to identify the available flows at each site.
The results show that approximately 103.6MW of potential capacity and 365GWh of potential generation are available at 373 identified sites on USBR canals. Although sites were identified in every of the bureau"™s regions, the highest energy generation potential is in the Great Plains, Upper Colorado and Pacific Northwest areas.


Energy and capacity by US state

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