Abstract
As the need for energy increases globally, the energy supply has been unable to keep pace with growing
demand. Renewable energy has seen substantial growth, especially in solar and wind generation, and
provides cleaner energy sources to help mitigate escalating environmental impacts. However, renewable
energy still only accounts for roughly a quarter of the US energy mix. To achieve a cleaner, more robust
electric grid and help reduce the energy supply gap, renewable energy sources need to be deployed across
all available environments. To that end, three complex environments and their unique needs are explored
to address wind energy generation system capabilities across various scales.
One environment is distributed wind, which serves as off-grid and behind-the-meter generation in
remote and rural areas where grid connection may not be readily available. Small- and medium-scale
distributed wind systems (10-100 kW) are a focus because they can be applied to residences and farms
more readily, but, due to their scale and design requirements, they often require additional aeroelastic
modeling support to enable reliable, detailed system design and analysis. One such capability lacking in
OpenFAST is a realistic model of the yaw-friction torque contribution at the nacelle joint, which influences
the passive dynamics that these wind systems rely upon. To achieve this, a Coulomb-viscous friction model
is implemented in OpenFAST and verified.
The second environment is mountain-based wind. Onshore wind has seen most of its deployment in
the Great Plains, where the wind resource is greatest, though mountainous regions with comparable wind
resource have seen little development. Mountainous terrain poses logistical and technical challenges distinct
from traditional flat-terrain onshore wind farm development, but there is currently a lack of site
identification to begin the design and investigation of the benefits of siting a mountain-based wind farm
within a region of interest. To help address this, a robust site selection tool, expected to be applicable across
a wide range of mountainous and non-mountainous regions, is presented and deployed in Southwest
Virginia to identify mountainous sites suitable for a wind farm comprising 5.3 MW turbines.
The final environment is floating offshore wind. Coastal waters provide high wind resources that can
only be reached with floating wind systems. Floating offshore wind turbines have been shown to be
technically feasible, but are currently too expensive relative to alternative energy generation sources. One
of the largest contributors to the capital cost of floating wind systems is the floating platform. To reduce
the cost of the floating platform, two next-generation floating wind systems, SpiderFLOAT (10 MW) and
RingPool (15 MW), and their unique platform designs are explored. SpiderFLOAT notably features a
compliant modular platform design, and the cost and dynamic response sensitivity to the geometric sizing
of individual components, as well as the influence of platform can-leg joint flexibility, are investigated.
RingPool builds on the joint flexibility concept and employs it in a hub-and-spoke platform design,
reminiscent of a bicycle wheel. A preliminary investigation of the platform pitch and heave rigid-body
properties of RingPool is explored within the global floating offshore wind turbine design space.
