Problem Statement:• Annual and inter-annual wind resources,

particularly for offshore sites, are highly uncertain

• Knowledge of both mean and turbulence characteristics of wind through the lowest 300 m of the atmosphere are needed for estimating annual power production and stresses on blades and drive train components

• Both advanced measurements and advanced modeling are needed

Project F1: Wind Resource Characterization

PIs: Eugene S. Takle (ISU) and William A. Gallus, Jr. (ISU)

Current State of Practice/Research• Wind resources in offshore coastal areas

typically are estimated from weather forecast models or regional climate models that are only weakly constrained by actual observations

• These models are known to have large

systematic biases for simulating near-surface conditions (lowest 300 m) even when compared against in-situ land-based measurements under conditions of strong vertical thermal stratification

Approach and Method

• Acquire new data from coastal shore-based towers and/or offshore tethered balloons to develop unique characterizations of the lowest 300 m

• Run the Weather Research and Forecasting (WRF) model over a small domain with high resolution (estimated 4 km horizontal grid spacing) centered over offshore regions of high interest for wind power development

• Use measurements and model output to develop new or refine existing parameterizations for use in the WRF model

Industrial Relevance and Benefits• Provide improved characterization of

mean winds and turbulence intensity in candidate high-wind resource offshore locations.

• Stimulate new methods measuring offshore winds and combining models and measurements of offshore winds.

• Improve estimations of annual wind farm energy production as guidance for financing

• Improve estimations of turbulence characteristics of high impact to turbine components

Deliverables and Project Plan• Task 1: Acquire existing coastal-region meteorological data

• Task 2: Acquire new data from coastal shore-based towers or tethered balloons to develop unique characterizations of the lowest 300 m of the atmosphere in forecast models

• Task 3: Run the Weather Research and Forecasting model for periods where data are available to constrain simulations

• Task 4: Apply revised model to multi-year simulations of hub-height wind speeds, wind shear and turbulence for multi-year periods Total Budget: $90,000 Project Duration: 24 months