Metocean Theme

Jiwen Fan, Lead, and Katherine Smith, Co-Lead

Goal: Determine how the wind resource and metocean environment, including the impact of extreme events, will change on time scales ranging from weeks to decades.

Meteorological and oceanic (metocean) conditions have significant, yet constantly changing effects on the availability of the offshore wind resource and the wind turbine’s environment. A combination of measurements and simulations will allow the team to estimate the wind resource in areas of potential floating offshore wind deployment. This theme also focuses on understanding how wakes from wind farms interact with metocean conditions and how metocean conditions will change in future climates across time and space.

Wind Farm Wakes and Wind Plant Inflow

Offshore wind farms directly interact with and alter the surrounding oceanic and atmospheric conditions by affecting waves and wind flows. Representing these processes in their full complexity is extremely challenging because they must be modeled in concert with the surrounding natural environment. This work seeks to create and test representations of how different floating offshore wind farms affect metocean conditions for use with the Department of Energy’s Exascale Energy Earth System Model (E3SM) for the first time. The developed parameterizations can then be applied to other Earth system models.

Figure showing visualizations from multiple simulations of wind energy fluid dynamics.
Visualizations from typical wind energy fluid dynamics at multiple scales. (a) and (b) are detailed simulations of flow over wind turbine rotors in uniform inflow and (c) shows low-velocity regions in a wind farm over a multiple-kilometer domain. (d) shows a view of an entire wind farm in an ~15 km long domain with streamwise velocity contours on hub-height and vertical planes (Shapiro et al. 2017). The short black lines in (d) show the individual turbines. (Image by Charles Meneveau | Johns Hopkins University)

Impact of Large-Scale Processes on Levelized Cost of Energy

Large-scale climate patterns and processes can affect the hub-height wind, temperature, and wind shear over the rotor diameter. These processes are dynamic and include extreme events with ever-changing frequencies. This work focuses on understanding and modeling how the large-scale climate will affect offshore wind regimes and wind farm operations under both the current and future climate. Simply modeling the current climate is insufficient to understand the long-term variability of specific locations for energy generation.

Figure showing projected changes in coastal upwelling
Projected changes in coastal upwelling, a process that is strongly affected by the large-scale climate. Yellow/red indicate increased upwelling and blue/black indicate decreased upwelling. The colored lines represent the projections of individual models and the bold, black line indicates the multimodel ensemble mean. The gray boundary represents ±1 standard deviation of the multimodel ensemble. (Figure: Rykaczewski et al. (2015))

Impact of Regional Coastal Processes on Levelized Cost of Energy

Regional coastal processes regulate metocean conditions and the wind resource at time scales of hours, days, and weeks. Large-scale processes provide the background metocean conditions, while variabilities at short time scales are determined by regional metocean systems. Coastal weather can change the wind resource. Research focusing on the U.S. West Coast seeks to understand how local conditions can alter the available wind energy as well as infrastructure costs. The approach will be twofold, looking at both common and extreme weather systems in our current and future climate. This work will also quantify the power produced across different weather scenarios, helping identify the impact of different weather on overall costs.

figure showing the Santa Ana winds
The Santa Ana winds sweep down from the deserts and across coastal Southern California. (Image: NOAA's National Weather Service | NOAA.gov)