Tech Briefs

S&P: U.S. hydro asset transactions experiencing renaissance

A report from S&P Global Ratings says hydro assets in the U.S. seem to be experiencing a renaissance, with recent transactions commanding substantial EBITDA (earnings before interest, taxes, depreciation and amortization) multiples.

“Hydropower Projects 101: How S&P Global Ratings Views the Risk of Hydro” says that although America’s hydro fleet of about 80 GW has remained largely flat since the 1970s, there is a resurgence in financing hydro assets. Factors cited are:

  • These assets continue to provide one major advantage to ratepayers: insulation against commodity price
  • Increasing decarbonization of North America makes hydro assets very valuable
  • The low power pricing environment that has weakened merchant generators’ fortunes during the past two years makes the case for maintaining hydro assets.
  • Incumbent plants retain significant value and are a scarce resource
  • With variable generation sources coming online, the ability of hydro facilities to adjust their production relatively quickly and offer load following services is becoming more valuable

The report says more than $6 billion of capital has been spent on hydro assets between 2005 and 2013 in the U.S. Key takeaways from this report, per S&P, are:

  • Despite hydrological and financial complexities, hydro fleets can be rated according to their resource risk, the risk of non-performance and liquidity features
  • A deluge of hydro closures is unlikely. Instead, these assets’ relative resilience and ability to renew via capital investments mean they are likely to play a significant role in the U.S.’ energy plans
  • Despite substantial proliferation of hydropower in the Pacific Northwest, it is possible that hydro imports from Canada could increase, given the favorable economic benefits of hydropower

A section on the Clean Power Plan says, “… we still believe that even if the new composition of the Supreme Court does not uphold the rule, there is likely to be some form of carbon regulation in the U.S. longer term, and, if so, the maintenance of hydro assets is likely to play a significant role in reducing carbon emissions.”

Pumped storage, conventional technologies get DOE funding

The U.S. Department of Energy has awarded $9.8 million in funding toward pumped-storage and hydroelectric power conversion technologies as part of its HydroNEXT program.The initiative is being administered by DOE’s Office of Energy Efficiency and Renewable Energy and seeks to make hydro development easier by advancing modular, cost-efficient innovations.

Selected for the pumped-storage sector were:

  • National Renewable Energy Laboratory will couple a ternary pumped-storage unit with “sophisticated” transmission monitoring and control equipment in a proof-of-concept for improving pumped-storage components’ integration into other renewable projects;
  • Obermeyer Hydro is developing reversible pump-turbines with submersible permanent magnet motor-generators. DOE said the scalability and versatility of this design makes it applicable for a number of storage projects; and
  • Shell Energy North America is investigating the feasibility of building a 5-MW closed-loop project that will include an artificial upper reservoir, a floating barge housing generating equipment, and a submerged, bag-like lower reservoir.

Selected to advance technologies for adding generation to non-powered dams were:

  • Canyon Hydro will further optimize the design of Archimedes screws for use in low-head, high-flow sites, while also looking to reduce manufacturing and transportation costs through modular designs;
  • Natel Energy will test a lab-scale version of its “hydroEngine” turbine, which it describes as a “linear Pelton”; and
  • Rickly Hydrological will design and lab test powertrain, modular infrastructure components and software designed to simplify small hydro development at non-powered dams.

Canada offers online aquatic species at risk maps

The Department of Fisheries and Oceans in Canada offers aquatic species at risk maps on its website, intended to help hydro developers determine if an aquatic species at risk or its critical habitat may occur in or near the zone of impact of a particular proposed hydroelectric project.

Users can find an area of interest by zooming in and clicking on a map grid. They can then use the resulting map page and species table to gain the desired information.

For example, clicking on the Pacific Ocean Map 1 grid reveals 32 aquatic species at risk in that region, from the basking shark to the yelloweye rockfish. Clicking on the leatherback sea turtle, an endangered species, reveals more detailed information, including action plans, order and recovery strategy implementation progress.


EPA releases fact sheet on aquatic life and hydrologic alteration

The U.S. Environmental Protection Agency and U.S. Geological Survey have released a fact sheet – Final EPA-USGS Technical Report: Protecting Aquatic Life from Effects of Hydrologic Alteration.

Hydrologic alteration is a change to an aquatic system and can include an increase or decrease in water volume, seasonal pulse flow disruption, dramatic variation in water temperature, and other factors. Sources of flow alteration cited in the report are:

Stresses on aquatic life associated with hydrologic alteration may be further intensified through climate change, which may change the frequency and duration of extreme weather events, EPA says.

The report presents a literature review of the natural flow system and a description of the potential effects of flow alteration on aquatic life; examples of narrative water quality criteria some states have developed to support natural flow and maintain healthy aquatic biota; and a flexible framework that can be used by states, tribes and territories to quantify targets for flow regime components that are protective of aquatic life.

The report is at


The third edition of Hydro Wheels: A Guide to Maintaining and Improving Hydro Units, by 30-year hydropower veteran Thomas Spicher, provides information to help operators diagnose and remedy common problems. The expanded version adds a chapter, “New and Upgraded Hydro Turbines,” which provides guidance in establishing long-term, highly-reliable service from turbines through procurement and specification improvements. Buy the book for US$41.30 at


Tech Briefs

Report released: Case studies on the benefits of dam removal

Headwater Economics released a research paper, Dam Removal: Case Studies on the Fiscal, Economic, Social and Environmental Benefits of Dam Removal.

In this 36-page report, the authors say: “While some dams continue to serve useful purposes, others have outlived their original function. For these obsolete dams, the benefits to the public of removing them outweighs the costs. It is appropriate to evaluate individual dams to determine whether their ongoing costs and effects on rivers and people justifies the services they provide.”

The report describes the methods used to measure the benefits of dam removal when compared with costs. It also includes five case studies ranging from small former mill sites to large western hydropower dam.

The report indicates that, for the Elwha and Glines Canyon dams, for example, the estimated cost of removal was $324.7 million but the estimated benefits were $5.38 billion: $5.3 million annually from increased commercial fishing, $33 million in personal income associated with dam removal, $43.8 million from 500,000 more visitor days annually, and $5.3 billion of improved well-being for the American public.

Schneider Electric named Clean Energy Company of the Year

Schneider Electric has been named Clean Energy Company of the Year by the Northeast Clean Energy Council. The award recognizes Schneider Electric for its leadership and contributions to the region’s clean energy economy, unwavering commitment to provide innovative business models, connected technologies and solutions, and significant deployment of clean energy in the Northeast region, a press release says.

“We believe that access to energy is a fundamental, basic human right. At the same time, we are also convinced that the current way of managing, consuming and producing energy is unsustainable,” said Kevin Self, Senior Vice President, Strategy, Business Development and Government Affairs, Schneider Electric. “At Schneider Electric we are energy optimists — we believe the solution is possible by using the technologies of today to help our customers manage their energy better.”

Schneider Electric specializes in energy management and automation and has more than 160,000 employees.

Technology tip: Dealing with threaded fasteners

Many nuances are overlooked in the application of threaded fasteners. With large shafts, often the most critical component is fastener integrity. Great effort is given to tightening and measurement of the elongation to assure the proper pre-load. But too often the locking mechanism is ignored. Direct welding of either bolt or nut will relax that pretension and provide a stress riser that will be a source of fatigue failure. Using a block to engage a flat of a hex nut is generally the best way to prevent rotation.

Smaller fasteners with 12-point heads can be fitted with matching arcs having 12-point configuration that can be welded without compromising the pretension. Socket wrenches can be sectioned to provide such arcs, or carbon steel heavy wall tubes may be broached to provide that match. Spring-lock washers are generally not suitable for locking high-strength materials. Locktite is a proven material for limiting rotation of an installed male threaded fastener with a tapped installation. Vibration is the reason threaded fastener loosen, so every effort should be made to limit the amplitude and frequency of vibration the element will be subjected to. Where nuts are used, non-metallic locking elements such as nylon insert ESNA (elastic stop nut) lock nuts work well.

Where stainless steel components are joined — such as the cone of a Francis runner or the blades, housing or trunnions of a Kaplan unit — the fastener should have adequate strength and resist galling. Nitronic 60 stainless steel provides both high strength and galling resistance and can be used as a nut, male threaded fastener or both.

— By Thomas Spicher, Hydro YES

OpEx Corner: Improper rope technique causes fall, injury

A survey crew was inspecting rock anchors on a dam structure. Improper rope techniques were used while descending, resuting in a fall and injury to the employee.

Review and incorporate the corrective actions and recommendations related to this event into your own procedures in order to prevent a reoccurrence.

Visit the National Hydropower Assocation’s OpEx database at to learn more and join more than 100 companies that are exchanging critical hydropower information in a secure environment.