M.S. thesis defense

Lydia Andriesen M.S. thesis defense

2:30 p.m. Wednesday, April 1
Duckering 353
Also available via Zoom

In partial fulfillment of the requirements for the degree of Master of Science in mechanical engineering from the University of Alaska Fairbanks College of Engineering and Mines, Department of Mechanical Engineering.

Thesis title: Annual Riverine Hydrokinetic Energy Resource in Remote Northern Microgrid Communities: A Case Study of McGrath, AK

Abstract: Riverine hydrokinetic energy, or RHK, has been proposed as a local renewable energy source for remote river communities in Alaska, but most resource assessments have focused on the gross natural available resource or only the open-water season. In northern microgrids, electricity demand is highest during the winter, yet the available under-ice river energy resource has not been well characterized. This study develops a method to assess the year-round riverine energy resources of the Kuskokwim River at McGrath, Alaska to determine whether RHK could meaningfully offset diesel generation in a remote northern microgrid. The City of McGrath, Alaska is a remote community on the Kuskokwim River that has developed an energy plan and is exploring potential integration of renewable energy to reduce energy costs and consumption, setting the stage for long-term energy success for future generations. Field measurements of discharge, water stage, wetted perimeter, bathymetry, and velocity profiles were collected in both open-water and ice-covered river conditions. These data were used as boundary conditions and to calibrate a 3D hydrodynamic model in Delft 3D FM that was validated over one year. Modeled velocity time series were used to estimate potential power output from a representative RHK turbine. In addition to estimating the theoretical river energy resource, this study evaluates the practical resource by considering year-round availability, turbine feasibility, river use, and community priorities when identifying potential deployment locations. Low fidelity grid integration modelling with HOMER Pro software evaluated what portion of community energy demand could be met by RHK at these locations. One potential location was identified along the rock embankment in the Kuskokwim River adjacent to McGrath where velocities in the thalweg are fast, approaching ~2 m/s in the summer. Water speeds at that location were reduced to approximately 1 m/s under the ice in winter. This body of work establishes a method to assess under-ice river flow behavior, with assessments performed and verified in chosen locations. The strategy developed to estimate river energy potential opens the possibility for RHK to meaningfully contribute to a community’s year-round energy potential.

Advisors: Daisy Huang, Eloise Petrone Brown