ORPC proposes to build, install and test the RivGenTM Power System, a hydrokinetic energy unit, at the Nenana hydrokinetic test bed and analyze resource and technology results.
Hydrokinetic devices are powered by moving water, placed directly in a river, ocean or tidal current. They generate power only from the kinetic energy of moving water. Alaska has significant potential for hydrokinetic development in both rivers and tidal basins. Most inland communities in Alaska are situated along navigable waterways that could host hydrokinetic installations.
The RivGenTM Power System is a compact, standardized, stand-alone power generation system, consisting of two proprietary advanced design cross-flow turbines directly connected to a proprietary underwater permanent magnet generator between them, all mounted to a structural support frame. This project will seek to collect data on many vital questions for all hydrokinetic projects, including environmental interaction, performance and efficiency, deployment challenges, support design, debris avoidance, and economics.
This project is a two-phase project, with Phase 1 activities being funded under the EETG solicitation. Funding availability for Phase 2 activities is yet to be determined.
Phase 1 will focus on finalizing site and technology concerns in preparation for technology deployment in 2012. Tasks include:
- AHERC foundation and debris diversion literature surveys, data collection and final reports completed Dec 31, 2010
- ORPC environmental and site characterization data collection for project design and FERC draft license application performed by October 1, 2010
- Prototype Bottom Support Frame And Debris Diversion system fabricated, deployed, tested, and retrieved at Nenana Site July – September 2011
- Additional field work required for Final Pilot License Application completed by Oct 31, 2011
- FERC Final License Application submitted by Dec 31, 2011
- RivGen™ TGU built and tested at Eastport Maine test site by Dec 31, 2011
- Final Report on Nenana site characterization work and foundation system and debris diversion system performance submitted by Dec 31 2011
- Final performance report on RivGen™ test in Maine submitted by Feb 15, 2012
In order to provide ORPC with appropriate recommendations for the development of a debris diversion/mitigation system, AHERC will first conduct a survey of literature on river debris and debris shield design and performance to facilitate the design of a measurement program and specific pieces of equipment. AHERC will then (1) measure debris at different depths in the water column from floating platform (2) measure floating debris visually using a video camera; (3) examine the performance of different test debris shield designs via suspension from the floating system; and (4) measure river current velocity ahead of and behind the test debris shields to determine the change in current caused by collected debris over time. The floating platform will initially be placed in a reduced velocity section of the Tanana River and then moved to faster sections as more experience and data are collected. Finally, AHERC will collect, analyze, and report the data. Data from this study will be used by ORPC to develop a debris diversion/mitigation system.
For the foundation, AHERC will first conduct a literature survey of existing foundation systems suitable for application in a riverine environment. AHERC will then review information from existing (already constructed) and active (being constructed) systems and visit ongoing hydrokinetic construction projects to acquire knowledge of prevalent foundation systems and develop an outline of various construction concerns in working in a riverine environment, how they may be mitigated, and how they may affect final design selection. AHERC and ORPC will determine the loads that the RivGen™ Power System will exert and formulate design criteria for the foundation system. AHERC's final report to ORPC will include a recommended approach to design of a hydrokinetic turbine foundation for installation in the Tanana River.
Final engineering details for the RivGen™ Power System will be completed after the data is received from the literature surveys and field season sub ice studies, and debris studies. Information from these studies is vital to the design of the support frame, which is integral to the RivGen™ chassis frame. The underwater permanent magnet generator and the ADCF turbine design specifications are complete. After completion of the final engineering of the RivGen™ TGU, the TGU will be procured, fabricated, and assembled and will be tested in the Eastport, Maine test site.
Phase 2 will include the completion of the project including deployment, testing and retrieval of the RivGen™ Power System at the Nenana site with reporting complete by Dec 31, 2012. Anticipated tasks include:
- RivGen™ TGU modified as necessary disassembled, packaged, and entire RivGen™ Power system shipped to Alaska arriving in Nenana by May 2012
- Foundation and debris diversion systems modified as necessary and prepared for deployment by May 2012
- FERC Final Pilot License Application received by June 2012
Hydrokinetic devices are powered by moving water and are different from traditional hydropower turbines in that they are placed directly in a river, ocean or tidal current. They generate power only from the kinetic energy of moving water (current). This power is a function of the density of the water and the speed of the current cubed. The available hydrokinetic power depends on the speed of the river, ocean, or tidal current. In contrast, traditional hydropower uses a dam or diversion structure to supply a combination of hydraulic head and water volume to a turbine to generate power. In order to operate, hydrokinetic devices require a minimum current and water depth. The minimum current required to operate a hydrokinetic device is typically 2-4 knots. Optimum currents are in the 5-7 knot range. Water depth is an important factor in the total energy that can be extracted from a site, since rotor diameter is dependent on adequate water level above the installed device. Hydrokinetic devices are ideally installed in locations with relatively steady flow throughout the year, locations not prone to serious flood events, turbulence, or extended periods of low water level.
ORPC has developed and successfully tested proprietary designs of the components of its technology and has filed U.S. and Patent Cooperation Treaty (PCT) utility patent applications to protect its intellectual property rights. The core of the RivGenTM Power System is the Turbine Generator Unit (TGU) which consists of two proprietary advanced design cross-flow turbines directly connected to a proprietary underwater permanent magnet generator between them, all mounted to a structural support frame.
The overall dimensions of the RivGenTM TGU is approximately 39 feet (11 .9 meters) wide by 9 feet (2.8 meters) high by 7.5 feet (2.3 meters) deep. The RivGenTM TGU is sized to allow the device to be shipped fully assembled in a standard "CONEX" container to remote areas. We anticipate mounting the RivGenTM TGU on foundations or pilings installed at the site or on a gravity foundation frame attached to the TGU. The unit, including a debris diversion or mitigation system, which will be either installed separately or attached to the RivGenTM foundation system, will be submerged to a prescribed depth below the surface of the water. No components of the system will be located or visible on the water surface. The technology does not require any impoundment, dam or diversionary canals in the river.
The power output for the present design of the RivGenTM Power System to be used in this project is approximately 30 kilowatts (kW) in a current speed of 3 meters per second. ORPC will continue to develop improvements in turbine efficiency as part of its RivGenTM Continuous Improvement Program and projects that the performance of the RivGenTM system can ultimately be increased to 50kW or more in a current speed of 3 meters per second. The proposed first generation RivGenTM Power System in the Tanana River will be installed as an individual unit. Once fully proven in this relevant environment, the RivGenTM Power System can be connected in a series of units along the run of the river. RivGenTM units can also be scaled up to a size that will generate up to 100 kW where depth and other site characteristics, as well as electricity load, allow for such a scale up (larger scale projects may require shipping in multiple containers.)
Data and Analysis
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Funding and Partnerships
This project is a Denali Commission EETG Program project. The funding goal of the EETG program is to develop emerging energy technology that has the potential of widespread deployment in Alaska and has the long-term goal of reducing energy costs for Alaskans.
ORPC’s technology and project development embody every aspect of this philosophy. We are one of the few companies in the world to generate electricity from tidal energy without using dams, which can upset the balance of marine environments, and we monitor our equipment carefully to ensure no adverse effects on sea life. We are in the process of obtaining federal licenses to install our power systems at some of the world’s best tidal and river energy sites—Western Passage, Maine; Cobscook Bay, Maine; Cook Inlet, Alaska; and Nenana, Alaska—and have developed these sites in collaboration with local communities, public officials, universities, environmental watchdogs, fishing industry groups, and other major stakeholders.
The Alaska Center for Energy and Power (ACEP), an energy research group housed under the Institute of Northern Engineering at the University of Alaska, Fairbanks, is serving as the program manager of the EETG solicitation. As the projects deal with emerging energy technology and by nature are high risk, high reward, ACEP’s technical knowledge and objective academic management of the projects, specifically for data collection, analysis, and reporting, is a vital component to the intent of the solicitation, i.e., providing lessons learned and recommendations.
Alaska Hydrokinetic Energy Research Center
AHERC, within the Alaska Center for Energy and Power at University of Alaska, Fairbanks will conduct literature surveys, review other hydrokinetic systems, and assist ORPC in developing a foundation system and a debris diversion system for the RivGenTM Power System.
National Renewable Energy Laboratory
NREL will provide project oversight through periodic review meetings scheduled at critical design and decision points throughout the project term.
City of Nenana
City of Nenana will provide continued project support by facilitating community meetings, project logistics, and through the donation of the use of their 100kW diesel generator for micro-grid testing of the RivGen™ Power System.
Nenana Native Council
Nenana Native Council has offered the use of its land adjacent to ORPC's Tanana River site for accessing the river and for project logistics and support.
SatCon Applied Technology
SatCon Applied Technology works with ORPC as a provider of power electronic and control system design, engineering and manufacturing.
PND Engineers, Inc
PND Engineers, Inc will work with ORPC to design a gravity based foundation for the RivGenTM Power
System and assist in obtaining civil engineering approvals for the structure.
HDR|DTA assists ORPC with management of environmental and other regulatory site studies and development and submittal of permit applications.
TerraSond Ltd. is ORPC's site characterization partner for Nenana and other potential river and tidal sites.
Project Links, Resources, and Documents
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