• Design of a micro-hydrokinetic electric power generation system

      Han, Rui (2011-08)
      The objective of this thesis project is to design a Micro-Hydrokinetic Power Generating (MHPG) system to generate electricity from sustainable and distributed hydrokinetic resources. The system is developed from a patent held by one of our team members, Robert Kallenberg. The MHPG does not require a dam or diversion, thus avoiding the negative environmental impacts associated with dams. The project could also help some communities to make use of their locally available hydrokinetic resources and significantly reduce their electricity costs. Reviewing of the literature in hydrokinetic electric power generation technology shows that hydrokinetic projects developed to date have largely made use of hydro turbine systems. These hydro turbines have a strong potential to cause fish mortality, while by design, the MHPG has little chance of causing mortality due to its gentle motion. On the other hand, the build-up of debris on a conventional hydro turbine can easily disable or even destroy the turbine, while the hydro foil in our device is generally oriented with the angle of attack less than 30 degree from the current, keeping debris build up at a minimum. The state of the art software COMSOL Multiphysics has been used as our numerical analysis tool. The interaction of water and the designed foil in a straight rectangular turbulent channel is modeled, explicitly, using two conservation laws: conservation of momentum and conservation of mass. The incompressible Navier-Stokes application mode in COMSOL Multiphysics has been used in this simulation to solve the distribution of the pressure and the velocity filed. Results show that the oscillating hydro foil has the potential to surpass the efficiency of a conventional turbine, and is deployable in relatively low velocity streams. Future project development suggestions will be presented focusing on further improvements electric machinery design and system integration. Finally, the prototype of the device has been fabricated and tested in natural rivers. The first test in Chena River, AK, verified the design by showing that the prototype can move in an oscillating manner. The second test in San Gabriel River, CA, shown that the designed Scotch Yoke, which was used to convert linear motion into rotational motion, could be efficiently integrated with the motion generation system. Future test work including permanent magnetic generator coupling and energy efficiency measurement need to be carefully studied concerning the system efficiency and maintenance.
    • Renewable energy development in Alaska: policy implications for the development of renewable energy for remote areas of the circumpolar Arctic

      Holdmann, Gwen Pamela; Johnson, Ronald; Peterson, Rorik; Greenberg, Joshua; Sfraga, Mike (2019-12)
      The territories that comprise the Arctic region are part of some of wealthiest and most advanced countries on the planet; yet, rural Alaska, northern Canada, the Russian Far East and Greenland--characterized by off-grid communities, regional grids, and higher degrees of energy insecurity--have more in common with the developing world than the southern regions of their own country. This thesis explains this paradox of energy development in the Circumpolar North and tackles the issue of developing renewable energy in remote areas where technical and socioeconomic barriers are significant. The primary research questions are two-fold: 1) Why did the Alaska electrical system develop as a non-integrated patchwork of regional and isolated grids? and 2) What are the major factors in Alaska that have resulted in a greater uptake of renewable energy systems for remote communities, compared to other similar places in the Arctic? This thesis demonstrates that state-building theory provides a cogent framework to understand the context of electrical build-out in the Circumpolar North. A major finding of this thesis is that the buildout of electric infrastructure in the non-Nordic countries, including Alaska, exemplifies a process of incomplete nation-building. Interconnected regional grids, where they exist, are largely due to the twin national priorities in infrastructure development in the north: extracting natural resources and enhancing national security. This thesis also draws on sociotechnical transition theory to explain why Alaska exhibits such high levels of energy innovation when compared to other similar regions across the Arctic. This research concludes that drivers such as extremely high energy costs, a highly deregulated utility market with dozens of certificated utilities, state investment in infrastructure, and modest subsidies that create a technological niche where renewable energy projects are cost-competitive at current market prices have spurred energy innovation throughout Alaska's communities, remote or otherwise. Many of the evolving technical strategies and lessons learned from renewable integration projects in Alaska's remote islanded microgrids are directly applicable to project development in other markets. Despite differences in climate and geography, lessons learned in Alaska could prove invaluable in increasing resiliency and driving down energy costs in remote communities world-wide.