Mark Christian - University of Tennessee
Mark is enrolled in the Energy Science and Engineering Ph.D. program at the University of Tennessee, an interdisciplinary degree program allowing students to attend classes at UT while performing research at Oak Ridge National Lab. Mark Christian’s primary research interest is in flow modeling and greater integration of alternate energy technologies into the national infrastructure. Mark is currently working with the Energy-Water-Ecosystem Engineering Group at Oak Ridge National Lab on creating a value analysis method for advancements in flow measurement accuracy. Advancements in flow measurement technologies have the potential to allow hydroelectric plant to operate more accurately on their efficiency curves and more effective allocation of water reserves.
He received his undergraduate degree in Ocean Engineering from Florida Institute of Technology, an interdisciplinary degree that addresses all aspect of engineering in respect the environmental challenges that are presented by the ocean. For his Senior Design Project Mark lead a research team to design, construct and deploy Wing Wave, a full- scale alternate energy device based on the motion of ocean waves.
Research- Development and Demonstration of Value Analysis Methodology for Hydropower Flow Measurement Enhancement
The hydropower industry is a well-established field with significant existing infrastructure and highly evolved practices for operation. This allows for consistent operation with little risk; however the risk aversion that is appropriate for facility operators also acts as a barrier to the deployment of enhancements in flow measurement (FM) technology within the field. The addition of new technology represents a significant investment to the infrastructure and without quantifiable benefits the hydroelectric industry is understandably reluctant to adopt it. The research will address this knowledge gap by developing a methodology to assess the value of enhancing FM accuracy through hydroelectric turbines. This methodology will be applicable to all hydroelectric facilities and will catalog the physical requirements, quantify costs, and quantify potential benefits of utilizing multiple flow measurement technologies. An additional goal of my project is to analyze the incremental value of corresponding incremental improvements in FM accuracy. This will enable the hydropower industry to evaluate individual facilities and technologies and select from a range of technology investment options to maximize value with available resources.
This research will review the existing standards and methods of FM and determine the turbine type and hydropower plant geometry that best suited to each method. The methodologies will be classified by: level of accuracy; support instrumentation; data analysis required; implementation cost; maintenance cost and schedule; and restrictions on use.
Additionally the research will assess of the rage of accuracy in FM that exists within the Hydropower industry. This will be done through a series of case studies on several sizes of hydroelectric plants utilizing a variety of turbine types. Further research in this area will be performed to understand potential for energy revenue gains; ability of FM to detect performance and infrastructure degradation; justification of upgrades; enhanced control of the facility; and retention of stored water resulting from increased FM accuracy. This information will then be used to quantify the values and feasibility of FM enhancement as a function of hydroelectric plant size, type, and operating history. This method will be compiled into a technical report that accounts for the various levels of production that exist throughout the hydropower industry and will recommend specific improvements tailored to each one. The paper will serve as both a comprehensive assessment of FM technology and also a method to allow the hydropower industry to make informed decisions on the method of FM that is best suited for specific applications.
Lisa Dilley - Washington State University
Lisa Dilley is a dairy farmer from western Washington State and earned a bachelor’s degree in physics from Centre College in 1996. She discovered her interest in watershed planning and local water and land use policy making through her membership in the Chehalis Basin Partnership and Washington Farm Bureau and enjoys local politics, building things, and outdoor recreation. To further her professional interest in water resource management, Lisa began studies in civil engineering at Saint Martin’s University in 2007. While studying at SMU, she served as a water resource engineering intern and helped advance ideas regarding flood mitigation and storage in the Chehalis Basin. Now at Washington State University, Lisa is studying basin management and riverine hydraulics.
Research- Economic Feasibility of Pumped Storage Hydropower in Systems with Seasonally Low Flows
This project will develop an optimization model for pumped storage hydropower as a multi-purpose water resource and demonstrate the regional economic potential for its development using the Columbia River as a case study. This model will serve as a tool for hydro development in the western U.S. and elsewhere, where seasonal low flows are prevalent, water demands and fish and wildlife provisions are putting additional stress on hydropower systems, alternative supplies are being evaluated, and the task of managing the water resources of the basin falls not only to federal U.S. agencies, but to local, regional, and international entities.
This pumped storage model will demonstrate the feasibility of developing pumped storage on a local and regional scale by determining the size and characteristics of suitable pumped storage reservoirs and taking into account the economic conditions under which the reservoir will be developed. Hydraulic capacity and power generation capacity – as firm capacity and as peak-leveling capacity – will be modeled in the context of the potential for providing water downstream for in-stream flows, municipal or commercial use, or to support additional groundwater withdrawals.
This model will serve as a tool for identifying sites that could be developed for pumped storage as well as for identifying the water resource partnerships that will make construction of new pumped storage cost-effective. It will also demonstrate the ability of proposed developments to serve the diverse objectives prescribed by regional power planning agencies, local renewable energy laws, and federal mandates. Furthermore, the implementation of this model into decision support tools will aid in the integration of power, economic and ecological objectives as concurrent goals rather than competing goals that result in win-lose decision making.
Using optimization software in Mathematica, the model will be optimized for size and flow requirements, construction costs, O&M and pumping costs, hydro generation, and water demand and marketability downstream. A case study will be developed for the Columbia River power system, using the system of dams on the main stem Columbia between Grand Coulee Reservoir and the confluence of the Snake River. This area is characterized by large agricultural withdrawals, high dependence on hydropower, significant wind-power penetration, and low summer flows in July and August. In addition, downstream of the study site, new water rights are in demand in parts of Grant, Adams, and Franklin counties, and water availability downstream could also affect the cities of Pasco, Richmond and Kennewick.
Stanley Dittrick - Washington State University
Stan Dittrick is pursuing his doctoral degree in Materials Science and Engineering at Washington State University, Pullman, WA. Prior to joining WSU, Stan worked at industry for many years. He became a journeyman electrician through Independent Electrical Contractors of Washington. He received an associate’s degree in energy technology from Centralia Community College. His undergrad work in chemistry was done at Western Washington University at Bellingham, WA. In 2011 he received his master’s degree in Materials Science and Engineering from WSU. Stan has published two journal papers and two more are being prepared for submission. He is hoping to be an expert to provide real world solutions utilizing novel materials in the energy sector.
Research- Novel Materials and Coatings for Reduced Erosion and Cavitation Damage of Turbine Surfaces
In the low temperature regime in which hydraulic turbines operate, the toughest materials are going to be those with the smallest grain size and hence reduced slip plane motion. The extreme condition of smallest grain size is no grains at all, in other words amorphous materials. Unfortunately metals readily form highly ordered crystalline structures and until recently had to be cooled from liquid temperatures to room temperature in micro seconds to form amorphous materials. This only allowed for very thin coatings and required extreme processing conditions to achieve amorphous coatings. More recently, research results have shown that the introduction of a large number of metals with different atomic radii significantly increases the time required for an alloy to crystalize.
Such compositions make it easier to cool the material fast enough to freeze the amorphous or glassy structure in place. One processing method which can create the high temperature gradients required to cool the material fast enough is freeform fabrication utilizing localized laser heating. Most of the part remains near room temperature only a small melt pool is allowed to reach high temperatures. The cool part dissipates the heat of these new alloys quickly enough to avoid crystallization of the metal.
Currently application of bulk amorphous alloy coatings on metallic structures to improve their wear resistance to minimize damage related to erosion and cavitation in turbines or other applications is being researched. In the work, there is an iron based “nanosteel” composition with a laser based freeform fabrication device to manufacture a wear resistant coating for turbine blades being used.
Coatings strength and adhesion are affected by energy input. Laser power and scan speeds are adjusted to make samples processed with different amounts of energy. These samples are tested and compared to a steel sample to determine how much improvements are made. Wear properties are determined using a computer controlled tribological testing in which samples can be placed in a controlled environment. Microscopic analysis is done using a scanning electron microscope (SEM) to understand structure-property correlation for these coatings. Once composition and processing parameters are established, such coatings can be formed using other commercial manufacturing methods such as plasma spray coating for large turbines.
Hosein Foroutan– The Pennsylvania State University
Hosein Foroutan is pursuing his doctoral degree in Mechanical Engineering The Pennsylvania State University. Prior to that, he received his Master’s and Bachelor’s degrees in Mechanical Engineering both as first-in-class (highest GPA) from Iran University of Science and Technology in Tehran, Iran. Hosein’s areas of interest include Fluid Mechanics, Turbulent Flows, CFD, and Turbomachinery. He is also very interested in teaching. He believes that hydropower has the greatest potential among renewable energy sources, and wants to contribute to this field through background and interest in Fluid Mechanics. After completing his PhD studies, Hosein plans to seek a faculty position and perform teaching and research activities. His long-term goal is to help developing more efficient Renewable Energy sources, as well as increasing the general awareness of this topic.
Research- Simulation, Analysis and Prevention of Vortex Rope Formation in Hydraulic Turbine Draft Tubes
The variable demand on the electricity market, as well as the limited energy storage capabilities, requires a great flexibility in operating hydraulic turbines. As a result, turbines tend to be operated over an extended range of conditions quite far from the design point (the best efficiency point). Hydraulic turbines operating at part-load conditions have a high level of residual swirl at the draft tube inlet. The decelerated swirling flow in the draft tube cone may lead to flow instabilities resulting in the formation of a helical vortex called the “vortex rope”. The vortex rope is now recognized as the main cause of severe flow instabilities, efficiency reduction, power swing phenomena, pressure fluctuations and vibrations experienced by a Francis turbine operating at part-load conditions. This becomes more important considering the fact that the shape of the efficiency hill chart of a low head turbine is governed by the performance curve of the draft tube; while the runner and vanes losses very smoothly over the wide range of operating conditions, the head loss of the draft tube increases dramatically moving away from the best efficiency point.
Given the strong effects that vortex rope can have, analysis and investigation of its formation as well as control or elimination of its effects are necessary for improving hydropower plant efficiency over a wide range of operating conditions, and preventing structural vibrations. This will be addressed in this research study. Therefore, the present study is directly related to the improvement of conventional and/or pumped storage hydropower technologies and operations.
Turbulent swirling flow in draft tube is currently being investigated numerically using a systematic, step-by-step approach starting from the simplest and advancing towards the most complicated flow structure. It is found that Unsteady Reynolds-Averaged Navier-Stokes (URANS) models cannot capture the self-induced nature of the vortex rope and result in steady solutions. By applying hybrid URANS/LES models detailed unsteady features of the flow can be captured sufficiently. Therefore, it is concluded that choosing the correct turbulence model is essential in modeling draft tube vortex rope. Studies at Penn State University also confirmed that the vortex rope forms due to the shear layer at the interface of an inner low velocity region (stagnant region) and a highly swirling outer flow. Therefore, a control technique including water jet injection from the runner crown cone downstream into the draft tube to mitigate the vortex rope is considered and investigated. The main idea is to increase the momentum of the stagnant flow in the centerline of the draft tube and to eliminate the high velocity gradients, which results in formation of the shear layer and helical vortex rope.
The research plan is to continue simulating flow in a real, elbow draft tube with vortex rope using CFD codes ANSYS-FLUENT and OpenFOAM. Simulations using DES (RANS near the wall and LES in the center) will continue. It turns out that RANS models cannot capture the enhanced production and diffusion of turbulent kinetic energy in the free shear layer created by the vortex rope. These models which cannot predict the vortex rope will be modified to fit this complex flow so that they could be used by designers to design draft tubes. This saves a lot of time in industrial practice where DES and LES computations take large amounts of time and storage, and are mostly suitable at this stage for academic research. Performance parameters of the draft tube will be calculated as a function of flow parameters such as discharge and head coefficients. Pressure fluctuations will be obtained and the effect of these on the draft tube structure will be studied.
Prevention of vortex rope formation by using water injection through the crown cone will be numerically investigated and its effects on the draft tube performance and pressure fluctuations will be obtained at various operating points on a hill chart. Water jet control of the vortex rope shows promising results for the cases studied within the preliminary steps of this research. However, further investigation of this technique for several operating points is needed. In addition, modification and optimization of the jet (flow rate, radius, and velocity profiles) will be considered.
Mohammad Hajit - University of Minnesota
Mohammad received his undergraduate degree in Civil-with a scholarship to KNT University of Technology. His undergraduate curriculum introduced him to a wide range of subjects, laying a strong foundation in Civil Engineering. During his studies he found a curiosity in the field of computational fluid dynamics which particularly captured his interest, which led him to pursue a masters’ degree in Hydraulic Engineering, at Sharif University of Technology.
After graduation, he worked in a private company performing numerical simulations of fluid flow and heat transfer for marine diffusers and open channels in the form of cascades in an effort to alleviate the adverse effects of high temperature plumes on marine biota. In 2009 he began pursuing a PhD at the University of Minnesota. His professional target is to become a research scientist and use his scientific achievements for the benefit of Civil/Environmental Engineering Programs and its relevant fields. He has chosen this stream as it satisfies his desire to create and to innovate. He believes this is the way he can, ultimately, benefit people. For career aspirations, he hopes to become a faculty member at a prestigious university or a professional researcher at a corporation.
Research- Hydroturbine Aeration Design Software for Mitigating Adverse Environmental Impacts and Increasing Hydropower Capacity
Decreased water quality ranks among the most notable environmental risks, in the form of depleted dissolved oxygen concentrations in the discharged water to the downstream environment. The impoundments necessary for creating sufficient hydraulic head to operate conventional hydroturbines lead to long residence times of upstream waters. Longer residence times allow processes such as fish and plant respiration to decrease the dissolved oxygen (DO) concentration, especially at greater depths in the reservoir. Water discharged downstream of the dam needs to have adequate levels of DO (5mg/L) to support the aquatic communities (ORNL 2010). Aerating turbines designed to increase DO are currently developed without sufficient experimental understanding of the sizes and breakup processes of bubbles that are generated by the entrainment. More specifically, the size and dynamics of the generated bubbles is guesswork that is not well understood. With well-verified software the turbine industry will be able to investigate different aerating turbine designs with CFD programs, thereby avoiding multiple cumbersome and expensive model turbine tests. Optimization of turbine configurations and operating conditions can be done prior to physical model testing and installation, therefore drastically reducing the installation and maintenance costs associated with conventional hydropower.
This research program seeks to develop a powerful computational tool for advancing the development and implementation of aerating turbines at U.S. hydropower facilities. It will also help reduce the adverse environmental impacts from, for example, the low tailrace DO common to hydropower facilities. Through improved efficiencies and decreased environmental impacts, this research effort will advance the capacities and reduce the cost of energy resulting from conventional hydropower technologies.
The proposed research is designed to develop advanced, efficient computational routines and software tools that can simulate conventional hydropower turbine aeration problems for advanced hydropower development. For this purpose, large eddy simulation (LES) of high-resolution fully turbulent bubbly two-phase flow based on purely Eulerian (two-fluid approach) and Eulerian/Lagrangian (bubble tracking techniques) algorithm will be developed. Large eddy simulation is achieved through the filtering operation to the governing equations of two-phase flows. Briefly, in this operation, we remove the noise/frequencies higher than the Nyquist frequency. Through this process, the microscopic governing equations are converted to macroscopic equations via spatial averaging of solution variables. This allows treating the phases as interpenetrating phases over the whole problem domain.
The next step is solving the governing equations numerically. The governing equations, i.e. momentum and mass transfer for each phase, constitute system of four partial differential equations solved in a coupled mode. The research will develop a code written in parallel C++ that allows the researcher to run the code by massively large parallel computations. To gain more flexibility on the geometry of the domain, curvilinear coordinate transformation form of the governing equations on which the equations are discretized and solved will be deployed. The equations are solved by efficient and popular “Krylov” subspace methods, e.g. GMRES. Different computational schemes and evaluate their accuracy and robustness for the advective, diffusive, pressure gradient, temporal and interfacial forces terms will be tested.
The validation for each solver has been conducted and validated for laminar two-phase flow. To tackle real scale problems, we will develop the turbulence model to be used for the LES formulation of the gas and liquid phases. This will allow the researcher to perform simulations of practical turbulent bubbly flows. The code would then be validated with a comparison of our results with experimental data. Finally, the component to account for the mass transfer (DO) from bubble plumes, released from turbine blades, to the water will be added. The procedure is similar for Eulerian/Lagrangian formulation except that tracking of every single bubble or pack of bubbles, and define some criteria to allow bubble breakup and coalescence will be done.
Andrew Hamann - Carnegie Mellon University
Andrew Hamann is currently pursuing his PhD in Engineering and Public Policy at Carnegie Mellon University in Pittsburgh, Pennsylvania. Andrew graduated from the University of Texas at Austin in May 2012 with a BS in Electrical Engineering. While an undergraduate, he interned for 15 months in the market strategy group at the Lower Colorado River Authority, an electric and water utility based in Austin, Texas. His experience there motivated him to attend graduate school to study and research the engineering and policy aspects of power systems.
His research interests are centered on how electric utilities can more efficiently use existing generation and infrastructure, for example by designing a more efficient control scheme for a hydropower cascade. Andrew enjoys basketball, walking, barbecuing, and the Texas Longhorns.
Research- Coordinated Predictive Control of a Hydropower Cascade
Over the past decade, there has been a sustained push to supplement and replace conventional power plants with renewable sources of electricity. Since renewables like wind and solar are inherently intermittent, their output must be augmented by other generation in order to maintain system reliability. This is typically done by ramping coal and gas power plants for small variations in output power, or by turning on quick-start combustion turbines if online reserves are insufficient or incapable of responding. This method is not ideal as it diminishes the environmental and economic benefits of renewable energy. Hence, balancing renewable intermittency through storage devices, demand response, and/or smarter grid management is the subject of significant research.
Luckily, a mature, cheap, and green source of energy already exists to balance these power fluctuations: hydropower. With fast ramping capabilities, immense storage volumes, and high levels of grid penetration, hydropower is ideal. The research question is: can cascaded hydropower plants be used to integrate and balance intermittent renewable generation resources by improving their control scheme? If so, what is the advantage of using hydropower over other storage mechanisms for this goal? How much renewable penetration can be achieved before system performance begins to degrade?
While there has been significant research studying this very problem, my objective is to model the hydrothermal power system with greater temporal and spatial resolution, enabling us to more confidently answer these questions.
The project will have three stages. In the first half, development and testing a coordinated predictive control framework for a hydropower cascade, which will fully harness the water energy stored in the cascade. This research utilizes an optimal control method known as Model Predictive Control (MPC) to anticipate the reaction of the cascade to a given control sequence. Using MPC and the system model, determine the optimal control sequence over a time horizon and apply the first control step in that sequence will be done. This control technique is analogous to thinking several moves ahead in chess and developing a forward-looking strategy instead of making a move that looks good in the short term but places you in a sub-optimal position later in the game. In this case, gains in operational efficiency will be accomplished both by reducing the amount of water that is spilled through flood gates when turbines are operating at full capacity and by retaining a larger hydraulic head behind the each dam.
The second half of the project will look at how disparities between electricity supply and demand can be balanced using a hydropower cascade. One of the advantages of MPC is its ability to incorporate predictions of system demand and generation variability to more optimally schedule system capacity. The research will robustly integrate forecast uncertainty by accounting for minute-to-minute variability in wind output and electricity demand, with the goal of realistically simulating the real-time operation and coordination of the hydropower cascade. If we can effectively shift the power regulation burden from conventional to hydropower generation, the economic and environmental benefits of renewable energy can be fully realized. The last part of the research will begin exploring how an MPC control scheme might be applied in a decentralized and/or deregulated market environment, with a special emphasis on supplying ancillary services.
Jordan Kern-University of North Carolina
Jordan Kern grew up in the Piedmont of North Carolina. As an undergraduate, he attended the University of North Carolina at Chapel Hill (UNC-CH), where he studied physical geography, GIS and remote sensing while working as a research assistant on a project studying the ecological effects of dam removal. Jordan earned a B.S. in Environmental Science in May 2007 and received a Phillips Scholarship in summer 2007 to study geothermal resources and regional effects of global warming in Iceland. Upon his return, Jordan worked for a consulting firm in the Washington, DC area, where he provided technical and administrative support to the US Department of Energy’s Hydrogen and Fuel Cells program. In spring 2009 Jordan enrolled in the UNC-CH Department of Environmental Science and Engineering as a M.S. student, where he is a Progress Energy Fellow. He currently works with Professors Greg Characklis (Environmental Sciences and Engineering) and Martin Doyle (Geography) on economic and environmental trade-offs between water resource management and the energy industry in the Roanoke River basin of North Carolina and Virginia. After receiving his M.S. degree in July 2010, Jordan will continue work at UNC-CH towards a Ph.D. with the support of the Hydropower Research Foundation.
Research- Dynamic hydrologic-economic modeling of tradeoffs in hydroelectric systems
In the Southeastern U.S., competition for water is becoming increasingly contentious due to rapid growth in demand. As state and regional managers seek to balance the water needs of humans and the environment, the timing of steamflows—in addition to their quality and quantity—is an important concern, and one that can be significantly impacted by hydropower generation. In de-regulated electricity markets, where the price of energy and grid reliability services change throughout the day, generators may have financial incentives to alter generation schedules, sometimes on a real-time basis, in order to increase revenues. Hydroelectric dams’ ability to respond to changes in electricity demand more rapidly and at lower cost than thermal generators (i.e., coal, nuclear and natural gas) makes them well suited to take advantage of short-term changes in market prices. However, the hydropower release schedules that result may lead to flow regimes that differ significantly from natural patterns.
My M.S. research at the University of North Carolina at Chapel Hill began to explore the potential for electricity market dynamics to impact flow regimes downstream from hydroelectric dams. Three dam sites in the Roanoke River Basin (North Carolina and Virginia) were modeled under several different operating scenarios. Flow regime statistics that reflect five environmentally critical components of river flow (magnitude, timing, frequency, rate-of-change and duration) were used to quantify the impact of different operational scenarios on downstream flows. Results yielded some insight into the complicated relationship between hydropower revenues and downstream deviation from the ‘natural flow regime’.
The Hydropower Research Foundation fellowship will be vital to my continued investigation of the relationship between electricity markets and flow regime downstream from hydroelectric dams. My Ph.D. project proposal involves the generation of stochastic hydrologic and market inputs, coupled with a probabilistic decision making algorithm on the part of the modeled hydropower utility, in order to set up a true revenue maximization problem. This enhanced model will also allow me to incorporate potential future impacts of climate change, increased reliance on more intermittent renewable energy sources (wind and solar), and changes in regional water demand from municipalities, industry and agricultural users. In order to gauge downstream environmental quality, a new set of flow regime statistics, ones that reflect potential hourly flow regime changes resulting from participation in dynamic electricity markets, will be developed and incorporated in our method for identifying a robust, Pareto-optimal solution for managing the hydrological assets of an entire river basin.
Kelcy Lajoie – Oregon State University
Kelcey Lajoie was born and raised in Eugene, Oregon. Growing up in the Pacific Northwest, she developed an appreciation for the natural resources around her. She attended the University of Portland as an undergraduate, where she received her BSEE in 2012, graduating magna cum laude. She has worked for Bonneville Power Administration since 2010 as a student intern, and through this experience has learned about the complex nature of the power system in the Northwest. Her passion to understand this intricate system fueled her decision to pursue a Master’s Degree. She is currently a graduate student at Oregon State University, pursuing her MS in Electrical and Computer Engineering, with a focus on Energy Systems. She hopes her research, in partnership with the Hydro Research Foundation, will help the engineering community better understand the complex relationship between hydropower and wind power in the Northwest.
Research- Advanced Study of Wind Power Variability on the Federal Columbia River Power System (FCRPS)
The Federal Columbia River Power System (FCRPS) is an incredibly valuable, but aging resource for residents and industry of the Pacific Northwest. Wind power in the PNW has increased at a nearly exponential rate, now reaching over 4,500 MW. Wind power adds variability to grid operation. In the Pacific Northwest, load and generation variability is handled largely with the regulation, following, and imbalance reserves provided by the FCRPS. However, preliminary studies by Oregon State University researchers have determined that the impact of wind on the hydropower system is less expected. Therefore, a greater in-depth analysis is required.
Hydropower’s characteristics make it an excellent partner for wind power, but to a limit. So far the FCRPS has been able to accommodate the large amount of wind power in the BPA balancing area, and as initial research has shown, with apparently surprisingly little impact on hydro unit life and operation. However, wind power is expected to grow rapidly with some estimates placing the maximum installed capacity reaching 8,000 MW. That is approaching the peak Bonneville Power Administration area load. There are indicators that a critical point n wind penetration may already be close at hand as evidenced by the occasional but significant wind power curtailment events in the last few years.
Researchers at Oregon State University have attempted to formulate a real-time damage incurrence (RDI) model for hydro turbines and energy storage systems based on data provided by Bonneville Power Administration and the US Army Corps of Engineers for the hydro units on the FCRPS. This model is to be used in creating a control algorithm that reduces the strain on the hydro turbines using a Life Extending Control (LEC) algorithm. The preliminary correlation between wind ramp events and hydro turbine ramping for the current levels of wind penetration in the Pacific Northwest. In fact, several hydro units appear to not be affected by wind ramp events at all. These results have been supported by similar studies conducted by interested parties at Bonneville Power Administration.
The proposed research will advance the study on exactly what wind power’s impact on the hydro-system is, and at what penetration levels it becomes significant. This research will also address how much of the wind power variability is effectively exported to neighboring balancing areas. The results of these studies will then be used to update the RDI model and cost functions used in the LEC algorithm currently being developed by Oregon State University researchers.
Daniel Leonard- The Pennsylvania State University
Daniel Leonard was born and raised in Philadelphia, PA. After graduating with honors from Central High School, Daniel attended Penn State University, where he developed an interest in fluid mechanics, obtained a B.S. in Aerospace Engineering in 2007, and a M.S. in Aerospace Engineering in 2010. Daniel chose to remain at Penn State in 2010 and pursue his doctorate in Engineering Science and Mechanics by studying computational fluid dynamics. At this point, he began working on his dissertation research by simulating cavitating flow in hydroturbines, under the guidance of Dr. Jay Lindau. Over the past few years he was a member of the Penn State hydropower research group, which conducts multidisciplinary research on many aspects of hydropower, where he gained a great deal of experience and interest in the industry. Daniel hopes that his research can make significant contributions to hydropower.
Research- Computation of Cavitating Flow in Hyrdroturbines
Cavitation occurs in hydroturbines when the flow conditions are such that the pressure on some mass of fluid drops to vapor pressure for a sufficient duration. If this condition occurs, a vapor cavity will form in the liquid. In hydroturbines, as in pumps and marine propulsors, cavitation can cause a sharp decrease in efficiency, as well as erosion from collapsing vapor clouds, resulting in premature wear and large component repair costs. Furthermore, it is the present trend in the hydro industry to attempt to extract more power from current and future installations over a wider operating range. Consequently there is more current and expected operation at off-design conditions, where cavitation is likely to occur. Thus detailed analyses to understand and improve runner cavitation characteristics are expected to be beneficial. Based on success with Computational Fluid Dynamics (CFD) modeling of other cavitating turbomachinery flow, it is fair to say that tools currently in use are capable of cavitating flow analysis through hydroturbines. Results of this analysis may be straightforwardly used to obtain accurate installed performance predictions as well as indications of potential cavitation damage and how it might be avoided.
This research effort will result in computational solutions of cavitating flow in an actual hydroturbine geometry. Steady solutions of cavitating flow will be obtained through periodic simulations of a single turbine blade coupled with a single guide vane. Additionally, to capture the temporal dynamics and the full coupling between stationary and rotating components, unsteady cavitation simulations of the guide vanes, runner blades, and draft tube will be performed using Unsteady Reynolds Averaged Navier-Stokes (URANS) methods, as well as Detached Eddy Simulations (DES). The unsteady, averaged unsteady, and steady computations will be compared to experimental data. The computed results will provide insight into unsteady and average cavitating hydroturbine operation, and extend the state-of-the-art in cavitation modeling. Furthermore, a better understanding of the dynamics of cavitation in hydroturbines will allow the hydroelectric power industry to operate more efficiently, not just as an energy source, but as a business.
Keith Martin - The Pennsylvania State University
Keith Martin grew up near Lancaster, Pennsylvania. He completed his undergraduate study at The Pennsylvania State University. In the summer of 2010, he participated in a hydropower research group where he learned to apply computational fluid dynamics (CFD) to turbomachines. He graduated with a BS degree in mechanical engineering in May 2011. Keith is currently enrolled in the graduate program in mechanical engineering at Penn State. His academic interests include fluid mechanics, turbomachinery, and CFD. Keith believes that hydropower is exciting field that is poised for growth and wants to contribute to the field through research on pump-turbines that can be found in pumped storage facilities.
Research- Analysis of the Effects of Pre-Swirl on the Efficiency and Operating Range of Hydro Pumps used in Pumped Storage Facilities
HInterest in wind and solar as alternative energy sources is growing. Although nuclear, hydro, and thermal plants carry a bulk of base load capacity, energy from sources such as wind and solar strain the electrical grid because they provide irregular levels of power. For example, photovoltaic cells only produce electricity when the sun shines, and wind turbines generate up to 70 percent of their power over nighttime when the demand for power is low. Various methods have been proposed to manage the electric grid, but hydro pumped storage plants are one of the most effective regulation systems available today.
Pump-turbines are turbomachines that extract energy from a fluid in turbine mode and add energy to a fluid in pumping mode. Pumped storage plants regulate the electrical grid by generating electricity at times of peak demand for electricity and storing energy by pumping water into elevated reservoirs at times of low demand. Pumped storage is one of the most economical energy storage methods, and plants operate at approximately 80 percent cycle efficiencies. Pumped storage also allows grid operators to quickly switch between power generation in turbine mode and energy storage in pump mode.
Fluctuations in the demand and generation of electricity can cause situations where power companies must buy excess energy. Pumped storage plants can store this excess power by pumping water to an elevated reservoir. In unique cases, operators may run a few pump-turbines units in pump mode while simultaneously running others in generating mode. This practice can result in poor flow conditions and decreased efficiencies.
Alternatively, the amount of power stored can be managed with variable speed pumps. Pumps traditionally operate at a constant speed at their peak efficiency point. Even though variable speed motors allow operators to vary pump capacity, changing pump speeds shifts the operating point away from optimum efficiency. One possible method of expanding the efficient operating rage is to adjust the amount of prewhirl at the inlet of pumps.
The proposed research focuses on the effects of pre-swirl on the operating range of pumps used in pumped-storage hydropower and renewable energy storage facilities. The goal of the research is to show that adjustable prewhirl can be used to expand the practical operating ranges of variable speed pump-turbines in pump mode without adversely affecting efficiency in generating mode. In turbines, wicket gates are used at the inlet to redirect flow and increase efficiency. In a similar manner, prewhirl in pumps can be achieved by adding directional vanes at the inlet of pumps to cause water to swirl as it enters the pump. Computational fluid dynamic (CFD) software will be used to predict operating conditions of a model pump at various inlet flow conditions. A case study will be conducted to determine the effects of pre-swirl on the efficiency and operating range of turbomachines in pumped storage facilities.
Tresha Melong - Worcester Polytechnic Institute
Tresha Melong is currently a graduating senior of the Class of 2012 in Environmental Engineering at Worcester Polytechnic Institute (WPI). She has had multiple opportunities to gain work experience, including as an internship at Pepsi-Cola Jamaica Ltd, in a teaching assistantship at the Ministry of Education in Jamaica and as a Health Supervisor for three consecutive summers with the WPI Summer Programs Office. These experiences have built her professionalism and work ethic and have allowed her to develop a clear set of career goals.
In addition to Tresha’s work experience, she also has participated in team activities. She was a member of the WPI dance team for two consecutive years, and a Peer Mentor for the WPI National Society of Black Engineers (NSBE). Tresha completed the Major Qualifying Project in collaboration with the Panama Canal Authority during their expansion project and her sophomore Interdisciplinary Qualifying Project was completed in conjunction with the City of Boston.
Research- Design of Hydropower Projects to allow for the Downstream Passage of the American Eel
The installation of dams or tidal and wave projects to harness hydropower energy has caused significant impacts on the life cycle of many marine species. Among these marine species are the American eels, where their downstream passage has become an increasing issue due to the significant decline in their population. This has resulted in the American eel being currently considered by the U.S. Fish and Wildlife Service to be listed as an Endangered Specie. The life cycle of this specie has been vastly affected by the construction of dams, which obstruct their migration corridors and subsequently results in the decline in its proliferation.
Some methods suggested for improving fish passage and protection at hydropower dams involve modifications and additions to engineered structures, which include the occasional use of sensory stimuli such as light, sound, turbulence, or electric fields to influence fish distribution. Other measures include spillways, bypass chutes or fish ladders at dams to provide non-turbine passage. However, the overall consensus to solving this problem would not only be to improve the design but to also focus on the water management (hydraulics and hydrology) aspects of the passage to ensure survival.
The aim of this research is, therefore, to find suitable intake flow and strategies to keep the eels out of the turbine with the use of sorting measures such as bar racks. From the environmental engineering point of view, a background in hydraulics and hydrology will allow for flow calculations such as the impact of the differences in head from upstream to downstream and designs to be made where marine life passage would not affect the hydropower generated by the dam.
The necessary literature review of downstream passage studies done for American and European eels will be completed, along with interviews with operators or staff at hydropower facilities that have incorporated fish passage designs. Evaluation of the designs used at the facilities that accommodate downstream passage of marine life will be completed using Computational Fluid Dynamics (CFD) software to study the hydraulic performance of each facility’s design. Laboratory study will be completed in collaboration with the Alden Research Laboratory (ARL) in order to validate models and test developed fish passage designs (different bar rack sizes) for hydraulic performance. Recommendations for bar rack fish passage designs will be developed according to the results of these evaluations.
Eliot Meyer- University of North Carolina-Chapel Hill
Eliot Meyer was born and raised in Houston, TX, with a six year interlude in Melbourne, Australia. He attended The University of Texas at Austin, where he received a B.S. in Civil Engineering and a B.A. in Plan II, an interdisciplinary liberal arts honors program, in 2009. While attending the University of Texas, he interned at the Federal Energy Regulatory Commission, and researched the nexus of water and energy in several capacities. Upon graduation, he interned with a nonprofit engineering firm focused on projects in the developing world. After receiving his M.S.E.E. degree from The University of North Carolina at Chapel Hill in December of 2012, Eliot began Ph.D. research under Greg Characklis (Environmental Sciences and Engineering), studying financial risk and water scarcity in a variety of contexts, including hydropower.
Research- Mitigating Hydropower Generators' Financial Risk from Climate Variability in Multi-Purpose Water Management Systems
The research will explore ways for hydropower producers to hedge against the financial risk of variable hydrologic conditions, especially on the Great Lakes. Variability in the hydrologic cycle has significant impacts on water storage and, by extension, on hydropower production and the revenues it generates. As such, this variability has important financial implications for hydropower producers, and concerns over even greater variability arising from climate change provide an increased sense of urgency.
The Great Lakes represent the largest freshwater storage system in the world, and includes significant hydropower resources. Great Lakes water levels are, however, highly variable on both annual and decadal timescales, with variability likely to increase as a result of climate change. Lower lake levels often lead to reduced hydropower generation, particularly when releases are also constrained by consideration of other uses. This reduction in power output must be compensated for through other, typically more expensive, sources or through purchases on the electricity market, creating a combination of lower revenues and/or higher costs that can prove very disruptive. Lake level management strategies must, as with many other storage facilities, balance many competing factors. These strategies may significantly impact the financial stability of hydropower producers by increasing their vulnerability to hydrologic variability. Nonetheless, these financial risks are not well characterized, and little work has been done to develop tools and strategies to mitigate them.
The research to date has focused on methods for reducing financial risk from water scarcity in a variety of contexts. Work has been done on developing financial tools for commercial shipping operations on the Great Lakes in the face of low lake levels. Whether designed as insurance or some other form of risk transfer instrument, these tools can provide adaptable methods for managing the economic impacts of hydrologic variability, particularly if the instrument is well designed.
A actuarial analysis of index insurance contracts based on the hydrologic dynamics of the system will de developed. This research will also involve testing different contract structures aimed at improving reliability and to compensate for revenue losses that occur under more and less severe events. Although some aspects of the Great Lakes make this work unique, these risk characterization and mitigation strategies are applicable to other multipurpose water management systems with hydropower facilities.
Ryan Morrison - University of New Mexico
Ryan Morrison was born and raised in Omak, Washington, a small town located near the Columbia River and Northern Cascade Mountains. His love of rivers and mountains led him to earn a Bachelor and Master’s Degree in Civil Engineering (emphasis in water resources) from Washington State University. After graduating from WSU, Ryan worked for four years at HDR Engineering, Inc. in Portland, Oregon, gaining valuable experience working on water resources projects dealing with hydropower on the Columbia River. Now pursuing a Ph.D. in Civil Engineering at the University of New Mexico, his studies focus on the interaction between ecological services, the ways in which human actions alter the services, and the best approaches for sustainably using natural resources for human development. Ryan is also a registered Professional Engineer in the state of Oregon. Outside of school, Ryan enjoys climbing, backpacking, and just about any other outdoor activity. He is looking forward to meeting this year’s other Fellows and working with the HRF on his research.
Research- Optimization of Reservoir Operations on the Rio Chama using Multicriteria Decision Analysis and Multiobjective Operational Reservoir Modeling
The World Commission on Dams argues that many large storage projects fail to produce the benefits needed to economically justify their development (2000). In many instances, additional constraints have been placed on hydropower operations, making it difficult for these projects to produce the full benefits as originally designed. These constraints can include interstate compacts, environmental flow requirements, industrial/municipal water supply, recreational enhancement, and altered hydrology due to climate change. Dams on the Rio Chama, a major tributary to the Rio Grande located in northern New Mexico, are typical of many existing projects throughout the United States that should be optimized to create improved and new benefits. Existing operations at El Vado, Heron, and Abiquiu Dams need to be closely examined and optimized to account for constraints not previously considered during the original project implementation. Also, additional benefits should be examined for the El Vado and Heron projects through the implementation of hydropower production.
The goal of the proposed research is to use multicriteria decision analysis methods and modeling tools to optimize dam operations on the Rio Chama.
The optimization process will include two analysis tools: multicriteria design analysis (MCDA) and computer modeling programs. A systematic decision framework will be used to account for multiple, conflicting demands while using the best and appropriate modeling tools for quantitatively assessing different alternatives. This is the first time flow optimization has been seriously examined for such a large watershed in New Mexico.
To achieve the research goal, three objectives are proposed:
- Advance multicriteria decision analysis in optimization of hydro operations. MCDA can be defined as a system that accounts for multiple demands or criteria while determining a solution to a particular problem (Belton and Stewart 2002). Although many approaches are available for applying MCDA, this study will use multiattribute utility theory (MAUT), an approach recommended by the U.S. Department of Energy (DOE) (1998). Through the use of utility functions, MAUT transforms different criteria, such as cost, stakeholder acceptance, and risk, into a common dimensionless scale (typically 0-1). Criteria utility functions are then combined with weighting functions of the criteria to form a decision score for each alternative (Kiker et al. 2005). The overall goal of this process is to maximize utility. The optimization framework will use MUAT to generate alternatives for testing and determine criteria with which to compare the alternatives. This will also involve assigning weights to each criteria based on its perceived importance.
- Investigate hydropower retrofit within an optimization framework. The installation of small hydropower facilities at El Vado and Heron Dams may provide an untapped economic benefit for reservoir operations on the Rio Chama. Recently added hydropower facilities at Abiquiu Dam demonstrate the practicability of adding low-head and low-flow turbines to older dam structures. The feasibility of adding hydropower to El Vado and Heron Dams will be examined, including approximate energy production capabilities and revenue based on resale to local energy distributors. A cost/benefit analysis will be performed to determine the approximate payback period for adding hydropower facilities at these sites.
- Demonstrate advanced tools on the Rio Chama. A management model, known as the Upper Rio Grande Water Operations Model (URGWOM), was completed in 2007 using RiverWare®, a program developed by the University of Colorado and used extensively by the Bureau of Reclamation, Army Corps of Engineers, and Tennessee Valley Authority for reservoir operations planning and management. RiverWare is the ideal modeling platform for testing optimization alternatives since it includes built-in algorithms for solving user-defined multiobjective operational policies. The URGWOM model will be the basis for modeling each optimization alternative. Operation rules that are economically and ecologically beneficial to the Rio Chama system will be fed into URGWOM. Optimization algorithms incorporated into RiverWare will be used to find operational solutions that comply with the previously established weighted criteria.
Kevin Mulligan- University of Massachusetts-Amherst
Kevin is a Research Assistant and Doctoral Student at the University of Massachusetts Amherst in the Department of Environmental and Water Resources Engineering. In 2012 he received his M.S. in Civil Engineering from the University of Massachusetts Amherst. In addition to his water resources research, Kevin recently received his specialization in fish passage engineering from UMass and is on the Organizing Committee for the 2013 International Conference on Engineering and Ecohydrology for Fish Passage.
Research- Cost-Effective Improvements to Surface Bypass Systems for Alosines
This research develops and evaluates fish surface guidance system designs to maintain hydropower efficiency under potential regulatory requirements aimed at protecting threatened and priority aquatic species. The research will demonstrate several designs that will improve surface bypass systems for alosines (American shad, blueback herring, alewife) by both guiding these species safely past a hydropower facility and minimizing hydropower production loss. The results will contribute to the industry’s understanding of how to best abate economic damages that would result from likely regulatory changes regarding these species.
Alosines are priority species for conservation and restoration on the east coast of the United States for numerous state and federal resource agencies (e.g. NOAA, USFWS, Maine DMR). In 2011, NOAA was petitioned to list some alosines (blueback herring, alewife) as endangered species. The recent petitioning for river herring, in conjunction with the prioritization of American shad restoration by resource agencies, incentivizes the enhancement of downstream passage efficiencies at hydropower facilities to prevent or minimize turbine injury. Alosine juveniles migrating out to sea require higher levels of protection than larger, juvenile Atlantic salmon. Therefore, juvenile alosines require tighter spacing to effect exclusion from turbines. Capital cost of and head loss due to full-depth exclusion racks is prohibitive. However, improvements to surface guidance technologies (e.g., racks, screens) that lead to bypasses may prove a more cost-effective way to protect these ecologically, culturally, and economically important.
This project is proposed in three phases. Phase one involves an extensive literature review focusing on the effectiveness of surface bypass systems for alosines. Phase two begins work at the S.O. Conte Anadromous Fish Research Center (CAFRC) by creating a bench-scale hydraulic model of numerous surface guidance configurations that enhance ‘sweeping’ velocities. Three different designs will be targeted for this project. Phase two will allow us to identify the best prototype for testing in the next phase. Pending additional funding phase three involves testing the prototypes effectiveness in guiding fish or a suitable surrogate at the experimental flume in the CAFRC and/or testing at a hydropower facility. Final deliverables include paper(s) on each design’s performance comparing energy loss versus alosine injury prevention.
The proposed research will be performed at both the University of Massachusetts Amherst and the CAFRC. The CAFRC is an exceptional research facility established by the U.S. Geological Survey designed to test experimental fish passages and hydraulic structures. The facility boasts a hydraulics lab, which consists of a 120 ft. x 40 ft. x 20 ft. experimental flume located off of the Connecticut River. This is a truly unique combination that will provide the ideal setting for this research project.
Minal Parekh - Colorado School of Mines
Ms. Parekh is a geotechnical engineer with over 15 years of experience in civil, geotechnical, and environmental engineering. She is currently pursuing a Ph.D. in Engineering at Colorado School of Mines, with research focusing on evaluating the integrity of existing earthen dams and levees using nondestructive methods. Ms. Parekh has served as a project manager, staff manager and mentor to junior engineers. Her practical experience includes design in support of water and wastewater infrastructure, shallow and deep foundation design, retaining wall and slurry wall design, soil and rock slope stabilization, specification and contract document preparation, construction submittal review, construction inspection, and construction management. Ms. Parekh has field engineering experience in projects that have involved geotechnical investigation, slurry wall construction, soil nail wall construction, rock slope stability, tunneling and trenchless technology, and pipeline construction. In addition to engineering consulting, she has worked in the public sector in environmental compliance, engineering design, and construction management.
Research-Valuating internal erosion in earth dams, using non-destructive methods
This research will advance methods for evaluating hydropower infrastructure using real time, continuous, and non‐destructive techniques. This research investigates earthen embankments (dams and levees) subject to water flow by exploring internal erosion initiation and propagation in heterogeneous earth materials and in zoned embankments. Internal erosion is a primary failure mode of dams and levees. There is limited understanding regarding characterization of the inception and early progression of internal erosion in earthen structures– both in terms of geometry of erosion features, properties within the seepage paths, and changes that occur with time progression. Research is needed to explore the accuracy and resolution required to capture changes in subsurface conditions using multi‐sensor, non‐destructive geophysical techniques deployed at the ground surface and/or in situ. Research is also needed to explore what parameters can be measured, how they can be used to diagnose where internal erosion susceptibility is high, how the parameters change with the initiation and progression of internal erosion over time and space, what scale of change in parameter can be measured, what the confidence of the measurements is in a probabilistic framework. The proposed research will motivate solutions to a significant challenge presented by earth dams which are susceptible to internal erosion as infrastructure ages. Colorado School of Mines is uniquely positioned to develop this research by working with local representatives from the U.S. Bureau of Reclamation (USBR) and U.S. Army Corps of Engineers, from within the SmartGeo Intelligent Geosystems program framework. (http://smartgeo.mines.edu) As a member of the program’s Intelligent Earth Dam research group, I am working to develop dam and levee systems that can sense changes in environment and performance and provide decision support for improving performance.
This research will focus on the geotechnical behavior observed at the initiation and early progress of internal erosion using continuous monitoring techniques (geophysical and imaging). Research will be conducted by experiment, analysis of results, and evaluation of dam and levee management policy related to advancing monitoring methods by addressing the following questions:
1. What does internal erosion look like as it initiates and progresses? Size, shape of erosion feature, surface deformations? Changes with time? Movement of particles? How do the material and hydraulic properties (porosity, density, permeability, flow rate) change as erosion initiates and progresses to form a continuous “pipe”? Experiment
2. Determine if we can detect the initiation/early stages of internal erosion using state of the art geophysical electrical/acoustic techniques? What size anomalies can geophysical techniques (electrical, acoustic) discern? What testing variables (sampling interval, electrode spacing) influence what we can see? Experiment
3. Using non invasive continuous monitoring, can we predict the location of susceptible soils, and probability of progression of the initiation of an internal erosion anomaly to a pipe? To a failure? Analysis
4. How does the ability to predict the occurrence of internal erosion dovetail into the risk assessment methods used by dam safety managers? How can we reduce uncertainties in the existing failure mode analyses and event tree models? Analysis/Policy
5. What are the implications of continuous monitoring to levee and dam management policy (and vice versa)? Policy
John Petrie - Virginia Tech
John Petrie is a candidate for the degree of Doctor of Philosophy in civil and environmental engineering at Virginia Tech. John’s areas of interest include river morphology, field measurements of river velocity, and computational hydraulics. His dissertation work focuses on the relationship between variations in discharge patterns due to hydropower operations and downstream riverbank erosion and stability. Prior to doctoral studies at Virginia Tech, John served as assistant professor of physics and mathematics at the Virginia Commonwealth University in Qatar (VCUQ) for three years. His professional activities include publications in journals such as Water Resources Research and Environmental Science and Technology and reviewing manuscripts for Earth Surface Processes and Landforms. In addition to his work in engineering, John received a Bachelor of Music in jazz performance from the New England Conservatory. John has performed on string bass across the globe from the Vancouver International Jazz Festival in Canada to Dunestock in Qatar.
Research- Modifying hydropower releases to reduce riverbank erosion
Through a combination of field surveys, numerical modeling, and analytical work, this study investigates the effects of hydropower peaking operations on erosion of the downstream riverbank and seeks to identify appropriate reservoir release adjustments to minimize these effects. Peaking operations, designed to generate electricity, result in dramatic changes in discharge often on a daily basis. For example, an almost ten-fold increase in discharge over two hours is typical on the lower Roanoke River. Erosion rates and conditions for stream ecology depend on the characteristics of hydropower peaking operations. Proper adjustments in the release patterns could mitigate adverse effects, further enhancing the appeal of hydropower as a renewable, sustainable energy source.
To predict erosion, three quantities must be specified: (i) the resistive capacity of the soil, (ii) the erosive force of the flowing water, and (iii) a threshold condition after which erosion occurs. To determine these quantities, this study uses a new approach to combine advanced field measurement techniques with computational fluid dynamics (CFD) models. Actual field conditions and flow releases on the lower Roanoke River, a regulated river in eastern North Carolina, serve as the basis for the study.
The resistive capacity and threshold condition of cohesive soils, such as those found on the lower Roanoke River, depend on the composition of the bank soil as well as chemical properties of the river and pore water. The complexity of interparticle forces has prevented the development of a general theoretical model to predict cohesive soil erosion. This study uses the in situ jet erosion test to determine the soil erodibility. The jet test uses a submerged water jet to erode the soil. The resulting scour depth is monitored over time to estimate the soil’s threshold shear stress and resistance to erosion.
To characterize the river flow and channel topography, extensive measurements have been carried out with an acoustic Doppler current profiler (ADCP) throughout the study reach. The ADCP provides direct measurements of three dimensional flow velocities and flow depth which may be used to determine discharge and bathymetry. The field data collected with the ADCP will be used to build CFD models representative of a straight reach and meander bend in the lower Roanoke River.
The erosive force applied by flowing water can be represented by the shear stress applied to the bank, known as the boundary shear stress. Boundary shear stress is influenced by the near- bank flow conditions, including the presence of secondary currents and turbulence. Direct measurements of boundary shear stress in natural rivers are not possible and techniques to estimate shear stress have been shown to provide significantly different results. CFD models are used in this study to calculate the distribution of boundary shear stress on the riverbank. CFD involves the numerical solution of the governing equations of fluid flows and can describe the entire three dimensional flow field. These models directly calculate the boundary shear stress based on local flow conditions. In addition to the shear stress, the models will allow a detailed study of the flow processes that generate the applied stress.
While this study focuses on the lower Roanoke River, the results will provide an improved understanding of the relationship between flow releases for hydropower generation and adjustments in the downstream river channel. Through numerical simulations of existing and alternative flow scenarios, recommendations can be made to minimize riverbank erosion. By reducing associated erosion, hydropower can continue as an important renewable energy source while minimizing the effects on the surrounding river and ecosystem.
Kathryn Plymesser - Montana State University
Kathryn Plymesser received her undergraduate degree in Civil Engineering in 2001 from Case Western Reserve University in Cleveland, Ohio. After working as a consulting engineer in land development for six years, she decided to return to graduate school full-time. She is currently a PhD Candidate in the Civil Engineering Department (Water Resources) at Montana State University and was recently hired into the Student Career Experience Program with the US Fish and Wildlife Service at the Region 5 headquarters in Hadley, MA. Her research work includes three-dimensional computational fluid dynamics modeling and fish passage energetics.
Research- Predicting Fish Passage and Energetic Requirements for the Alaska Steeppass Fishway using a Computational Fluid Dynamics Model
The proposed research project will characterize and quantify the hydrodynamic characteristics of a Model “A”, Alaska Steeppass fishway using a computational fluid dynamics (CFD) model. The CFD model will be used to help estimate energetic requirements for fish passage to better predict the probability of passage for species such as the American Shad (Alosa sapidissima). The probability of fish passage will be estimated by comparing three-dimensional velocities from the CFD model with swim speed-fatigue curves for the target specie. Energetic requirements for passage will be estimated using the methods outlined by Behlke (1991) and Webb (1975). The estimated energy requirements and passage efficiencies will be used to compare the relative effort required for ascent for standard configurations of slope and flow rate. In addition to providing a thorough understanding of Steeppass hydraulics, this study seeks to outline a method for analyzing fish passage efficiency and energetic requirements for passage using a CFD model. Relationships derived from this model may be used to modify the current design and recommended operating range for the Model “A” Steeppass fishway.
The Alaska Steeppass is a type of chute fishway used extensively on coastal streams in the east and in remote locations throughout the country. They are primarily suited to small streams and low head dams. Many of these streams historically supported spawning stocks of anadromous species. Much of this spawning habitat has been fragmented by dams to provide power and irrigation water for surrounding populations. Chute fishways of differing types (pool and weir, baffle, vertical slot) have become a popular solution for this problem. The Alaska Steepppass, a baffle-type chute fishway, was originally developed by Ziemer (1962) for use in Alaska where sites are often difficult to access with construction equipment and materials. These fishways have the advantage of being highly portable and relatively inexpensive. Flow patterns in the Steeppass are complex and air entrainment is high which may contribute to passage difficulties for some species (Haro, et al. 1999). The Model “A" Steeppass, a derivative of the modified Denil No. 6 developed by McLeod and Nemenyi in 1940, is the most widely used variant due to its ability to reduce flow velocities to magnitudes theoretically negotiable by many species. Although the design criterion for the Steeppass fishway is generally accepted there is room for improvement, especially in the capability to efficiently pass a wider range of species.
Since its design in 1962 the efficacy of the Steeppass design has been evaluated on several occasions. Ziemer (1965) first reported on the apparent success of the fishway in an addendum to the original informational leaflet that describes the Steeppass design. More recently, researchers at the S.O. Conte Anadromous Fish Research Center quantified the effect of slope and headpond (flow rate) level on the passage of American Shad through the fishway (Haro, et al. 1999) and reported passage rates of 7 to 12 percent. This fishway was designed based on one-dimensional velocity characteristics which were reduced to a level navigable (in theory) by many species. Improving passage rates for anadromous clupeids in this fishway is a desired outcome of this project. Recently, fish passage researchers have begun to undertake the numerical simulation of hydraulic systems to improve design and operation of fishway structures based on three-dimensional hydrodynamics. To date, a numerical study of the hydrodynamics of a Steeppass fishway has not been published.
Chris Schleicher- Lehigh University
Chris Schleicher is pursuing his Ph.D. in Mechanical Engineering at Lehigh University and is a Research Assistant under the direction of Dr. Alparslan Oztekin. Chris graduated Cum Laude at York College of Pennsylvania with a BS in Mechanical Engineering in 2011, and completed a MS in Mechanical Engineering at Lehigh University in 2012. In his undergraduate years, Chris spent a year as a co-op student at Voith Hydro in York, PA working on projects in the Research and Development group in the Hydraulic Engineering department. This experience heightened his interest in hydraulic machinery and computational fluid dynamics (CFD). His research has encompassed the design of a person-portable hydrokinetic turbine and non-uniformly pitched Archimedean screw turbines.
Research- UPump-storage Hydropower Design and Implementation in an Urban Setting
Pump storage continues to be an increasingly popular topic. Power facilities that make use of pump storage hydro (PSH) are actually consumers of power more than producers of power; however, because the price of electricity is cheaper during off-peak consumption hours these plants are able to turn a profit. Typically these plants are near geological differences in elevation because of the need for an upper and lower reservoir to store water. This project entails making this technology more available in a micro-hydro sense rather than a large scale. More specifically this project is investigating using a pumped storage system in an urban, commercial environment.
Such a system would be of interest to commercial buildings with high-energy consumption such as those with large network servers. A considerable amount of money is spent to keep such servers cool and operational each day. The implementation of a micro-hydro pumped storage system would entail drawing from a storage tank on the roof of their building during peak power production hours, and pump the water to the roof during off-peak production hours overtime saving money on their electricity needs.
The scope of this project is to conceive the implementation of a pumped-storage system in this micro-hydro sense. This project entails the design and optimization of this system using CFD and Structural Analysis tools. The goal of this being to derive a runner geometry capable of handling the turbine and pump process, determining a prototype package that could be installed in a urban setting consisting of a possible reservoir-turbine/pump-reservoir system and turbine-generator component. A marketability and break-even study is also being conducted to investigate how feasible such a system could be in an urban setting.
Heidi Smith- University of Idaho
Currently, Heidi is conducting her Ph.D. research at University of Idaho’s Center for Ecohydraulics Research in Boise Idaho and focuses on sediment transport processes in river systems and asks why rocks begin to move. She is interested in the physical processes involved in river systems, as a basis to better understand how we may improve habitat for the dependent biological systems. Previously, she completed her undergraduate studies at the University of California, Santa Barbara with a Bachelor of Science degree in Environmental Studies that emphasized in hydrology. As an Idaho native, she grew up turning over river rocks, fishing, and crossing rivers in the Rocky Mountains, and has ever since been fascinated with these systems. Upon graduation, she would like to continue giving back to the river systems that have given her so much. To do this, she looks forward to continuing research on river systems, as well as working with her local community to help improve their understanding and knowledge of rivers and how we may best coexist with them.
Research- Improving on Hydropower Mitigation Success by Refining Predictions of Grain Motion
The federal hydropower relicensing process requires mitigation for the potential effects of dams upon habitat. Habitat can be adversely affected by the coarsening of bed material due to the cutoff of supply of gravel from upstream of dams. This grain size range is an important component of habitat for macroinvertebrate communities as well as for spawning habitat for salmonid species. During the relicensing of the Klamath Hydroelectric Project, mitigation for the impact upon the sediment supply downstream of the dam was addressed. In this example, the gravel stores were restored in order to improve channel complexity and spawning habitat for the resident anadromous salmon populations through gravel augmentation.
River restoration projects, often the means for mitigation, have cost billions of dollars in the US alone, and are most often unsuccessful. Thus, increasing the success rate of restoration projects is important. In restoration projects, the flows that cause grains to move is predicted using the reach-averaged shear stress, which is measured using flow depth and slope. This method often results in poor estimations of grain motion because it does not include turbulence, which causes a wide variability of forces on sediment, and local variation in the positioning of sediment upon the bed that causes variations in grain stability.
Until recently, these measurements of local forces have not been obtainable, but their inclusion is essential to improve of motion predictions. Sediment transport rate predictions are also greatly affected by our ability to accurately predict the onset of grain motion. Current sediment transport equations poorly predict sediment loads and are often off by a few orders of magnitude. Consequently, improving grain motion predictions will help to estimate sediment fill rates from upstream, which is central knowledge to plan for future energy production, as well as dredging costs. In summary, accurate predictions of sediment motion are beneficial for relicensing mitigation efforts as well as estimating future change in both energy production and operation costs due to reservoir fill by sediment.
To improve on the predictions of grain motion, the research will complete three general tasks. First, through a set of flume experiments, measurements the effects of turbulence on grain motion will be examined. The results from flume experiments to build a model that predicts the motion of grains in rivers will then occur. Finally, during three field seasons in Brunni, Switzerland, data was collected to test the proposed model. To accomplish the goal of the research, monitoring the motion of over 500 grains of varying sizes to test how well the developed model will predict grain motion. Overall, this tool will improve mitigation efforts for relicensing procedures by increasing the longevity of restoration projects downstream of dams, as well as estimating future change in both energy production and operation costs due to reservoir fill by sediment.
Karen Studarus - University of Washington
As a resident of Seattle, Karen enjoys diverse benefits from the Federal Columbia River Power System; self-interest, therefore, bolsters her professional curiosity about the competing constraints and objectives that form the short- term hydropower scheduling problem. Karen earned her B.S. degree in Engineering from Harvey Mudd College in Claremont, California in 2003. She worked as a research engineer at SAIC before coming to graduate school at the University of Washington to study statistical signal processing. At UW, she discovered her enthusiasm for one application of those techniques: integration of stochastic renewables with the electric power system. She shifted her focus to Power System Economics and Operations and joined Professor Rich Christie’s Wind Integration Research Lab. In addition to pursuing the Ph.D. in power systems analysis, Karen reads avidly, loves hiking and biking through the Pacific Northwest, and enjoys learning languages (especially when putting them to use with international travel).
Research- Understanding Operational Flexibility in the Federal Columbia River Power System
The Pacific Northwest has a spectacular energy resource in the Federal Columbia River Power System (FCRPS), an abundant and versatile source of inexpensive carbon emission free power. But the FCRPS serves many masters; it is managed for flood control, fish and wildlife, public safety, irrigation and recreation. All of these uses constrain the system’s deployment for power generation, as do transmission congestion, load obligations and non-federal hydro and wind generation. Every one of these considerations inflates uncertainty.
The optimization algorithms that are currently in use neglect some of these constraints and thus often return infeasible solutions. As human hydro schedulers must consider all the constraints, competing objectives, and uncertainty, they need to know how much flexibility they have and how best to deploy this flexibility. Hydro resources are often described as being the ideal counterpart for intermittent and stochastic renewable energy sources such as wind and solar. However, the services provided by hydro flexibility on the load following timescale have never been in higher demand.
Every hydro system is different, especially when considered at this level of detail, so we will analyze the Federal Columbia River Power System (FCRPS) managed jointly by the Bonneville Power Administration (BPA), the U.S. Army Corps of Engineers, and the Bureau of Reclamation. The work seeks to bridge the gap between academic hydro scheduling formulations and the practical realities of balancing a power system in real time in the face of uncertainty. Initial results will be specific to the inputs supplied by our partners at BPA, but the open source tools created to perform the analysis will be designed to readily answer the same questions for an arbitrary hydropower system’s parameters and historical time series.
Ever improving hydropower coordination optimization algorithms abound in the literature, and are even being explored by other Hydropower Research Foundation fellows. A chasm remains, however, between academically important formulations and the real time decisions of a hydro duty scheduler. Our work seeks to bridge this gap by focusing empirically on how the system is dispatched on an hourly and sub-hourly basis. We will analyze historical time series, rigorously explore all constraints and objectives, and probe assumptions about uncertainty. We will compare feasible system operation with the necessarily simplified theoretical optimizations.
As we model the FCRPS short term scheduling problem in increasing detail, we will repeatedly pose the following questions:
1. How much wind can the FCRPS accommodate before failing to meet other obligations, and at what cost?
2. How does historical scheduling differ from theoretically optimal formulations in the literature, and what real world obligations drive the divergence?
3. What output space of possible schedules do the constraints define, and what intuition about feasibility and flexibility does this grant?
4. Under what circumstances may reserve requirements have been unnecessarily constrictive (and expensive) or relaxed (and risky) as an operational protection against forecast and model uncertainty?
5. What strategies can BPA consider in future operation to maximize the value of the hydro resource?
Adam Witt - University of Minnesota
Adam Witt graduated from Carleton College, Northfield, MN in 2006 with a BA in Physics and a concentration in French and Francophone Studies. Prior to entering graduate school he worked four years as a management liability underwriter and national technology analyst in both St. Paul, MN and San Francisco, CA, earning the underwriting professional designation (CPCU). Adam began graduate study at the St. Anthony Falls Laboratory at the University of Minnesota in September 2010, completed a Masters of Science in June 2012 and is currently pursuing a PhD in Water Resources Engineering. In 2011 he helped develop a social venture to improve access to clean water for residents of New Delhi, India, and won a grant to spend three weeks in a field study in Bangalore developing a business plan. The social venture was selected as a semi-finalist for the 2011 Minnesota Cup, an annual, statewide new venture competition. His current research interests include hydrodynamics, hydraulic structures, bubble-water interactions, CFD using OpenFOAM, gas transfer and social ventures with a focus on water and sustainability.
Research-Developing a Technology To Predict Gas Transfer at Low Head and High Head Structures
My proposed research involves developing a technology, which can predict gas transfer at low head and high head structures. The goal is a unified theory and computer code that will function to predict oxygen transfer at low head structures, and oxygen and nitrogen transfer at high head structures. If the physics and chemistry of gas transfer at spillways can be accurately analyzed, the science of the process should not change with scale. The resulting equations can be used to solve gas transfer problems at multiple structures: locks, dams, spillways and hydropower facilities. Detailed analysis using traditional computational fluid dynamic (CFD) modeling would be implemented with field verification from existing measurements. OpenFOAM, an open source CFD solver, will be used to simulate the hydrodynamics of spillway flows. Modifications to the source code will be made to account for air entrainment and bubble breakup. If necessary, selective experiments will be developed and run to estimate the importance of particular physical processes.
Hydropower generates enough electricity to meet the needs of about 35 million residential customers.