Low-Cost Wind Energy Through Dense VAWT Arrays: Fatigue Loads and Power Performance Risk Mitigation

The proposed technology will boost the power production and increase the density of utility wind farms, resulting in at least a 23% reduction in levelized cost of energy (LCOE) from the wind while simultaneously utilizing wind resources more effectively. This disruptive drop in wind energy costs will increase the penetration of cost-effective wind energy. The flow dynamics of vertical-axis wind turbines (VAWTs) enable constructive interactions between rotors in a wind farm resulting in an increase in power of up to 30% over non-interacting turbines, and an increase in density per unit land-area of an order of magnitude compared to state-of-the-art wind farms. In Phase I of this project, simulations are performed to examine the impacts of close turbine spacing on rotor fatigue and power performance. Control and power output optimization algorithms for coordinated control of pairs of VAWTs will be formulated. In Phase II, two 25 kW VAWTs are installed at a field test site on moveable foundations and instrumented for rotor loads and power production measurements. Fatigue load, performance, and optimal control set points are determined as a function of rotor pair orientation compared to wind direction. The impact of performance gains and fatigue loading on the LCOE is analyzed. Field data is used to tune XFlow’s existing VAWT array optimization software, which is used to demonstrate the potential for market penetration.