The Effects of Summer-Only River Energy on Microgrid-Size Battery Energy Storage at High Latitudes

Abstract

Riverine hydrokinetics (RHK) represent an emerging technology in the renewable energy space with commercially-deployable systems on the horizon. In Alaska, many rural and remote communities exist on major rivers and are burdened by high costs of electricity and imported fuel, making them a promising end-user of these systems. However, it remains an open question as to how the addition of RHK will affect grid performance and electricity costs. Specifically, this study looks at the effects of integrating riverine hydrokinetics on a hybrid diesel microgrid with solar and battery infrastructure. Using real electrical load data and riverbed transects, estimated RHK costs, and modeled solar photovoltaic and river energy resources, a HOMER model was used to analyze the effects on battery degradation, and then expanded to look at fuel usage and levelized cost of energy. The addition of summer-only hydrokinetics was shown to have negligible impacts on battery performance and no impact on battery lifetime. Fuel savings were proportional to RHK size at lower penetrations, but diminished at higher penetrations due to significant curtailment. The estimated capital and operational costs of the RHK predicted an increase in LCOE for all scenarios, ranging from 16% to 39% with increasing system size.