Abstract
Alaska is home to over 100 remote riverine communities that are largely served by diesel microgrids. Wind, solar PV, and battery storage technologies have made significant inroads in many grids, displacing diesel and lessening the local environmental impact of electricity generation. However, the high variability of wind and solar resources creates technical complexity when penetration levels become significant. On Alaska’s two largest rivers, the Yukon and Kuskokwim, most communities have total electrical loads of a few hundred kW while multiple MW of steady river power flows by continuously during the open water season from early May to late September. The potential for hydrokinetic energy systems to harness this resource is of significant interest to these communities and their electrical utilities.
Alaska Hydrokinetic Background
In 2013 and 2014, vertical axis turbines rated at 5kW and 25kW were deployed in the communities of Ruby and Eagle Alaska, respectively [1], [2]. While both turbines successfully produced power, both efforts were discontinued due to damage incurred from interaction with woody debris present in the river. From this experience, the Alaska Center for Energy and Power (ACEP), an applied research group at the University of Alaska Fairbanks, initiated a research program devoted to studying solutions to deploying hydrokinetic technologies in Alaska[3]–[8]. As part of this effort, the Tanana River Test Site (TRTS) was established in Nenana, AK, to provide an accessible and pre-permitted location to perform hydrokinetic turbine testing and study debris interactions and other parameters key to economic implementation of riverine hydrokinetic energy in Alaska.
BladeRunner Energy Hydrokinetic Turbine
BladeRunner Energy (BRE) is a hydrokinetic turbine developer in Bend, Oregon. BladeRunner’s turbine design utilizes a minimally constrained submerged axial-flow rotor connected to a floating generator housing via a torsional cable. The torsional cable carries the drag load of the rotor and transmits the torque to the generator driveline. This design enables the rotor to translate, pitch, and yaw to absorb debris impacts, deflect around large debris, and shed small debris. A schematic of the BRE turbine architecture is shown in Fig. 1
Under the US Department of Energy’s ARPA-e SHARKS program, BladeRunner Energy and UAF have embarked on a multi-year effort to iterate BladeRunner’s turbine technology and field test it at TRTS. This paper summarizes findings and results of field testing a BRE system with 1.57 m diameter rotor and a rated output of 3.0 kw at 2.0 m/s