Seasonal Variability of the Surface Heat Flux Generated by Offshore Wind Farm Clusters in the Mid-Atlantic

Offshore wind power has the potential to provide more than two times the current nationwide demand for electricity, with nearly 80% of that demand within the United States found amongst the coastal states. This inexhaustible supply of clean, renewable power, located close to the constant energy demand of coastal cities, makes wind power a relatively inexpensive and low-emission alternative to fossil fuels. The United States is capitalizing on this abundant wind resource to generate the most power possible by building wind farms, or clusters of gigantic wind turbines that are densely packed together.

Modeling studies must be utilized to determine how large wind farms affect the environment. Each wind turbine modifies the surface heat flux of the environment due to the enhanced vertical mixing induced by the rotor disk. The “extreme scale” turbines being built along the mid-Atlantic Coast induce cooling below the rotor disk through this enhanced mixing, causing a positive change in the downward negative heat flux, which implies a reduction of temperature near the surface. The effect of the turbines on the surface heat flux is studied using a year-long Weather Research and Forecasting (WRF) micro-scale modeling dataset, provided by CU Boulder, which parameterizes the effects of 1,418 wind turbines, each rated at 12 megawatts (MW), on the boundary layer. Because the enhanced mixing caused by the rotor disk can redistribute temperature and moisture profiles within the boundary-layer, offshore wind farms may cause cooling, warming, or increase relative humidity near the surface. The impact of large clusters of offshore wind farms on air-sea fluxes will be analyzed to determine if the near surface temperature changes induced by the turbines could influence long-term climate patterns in the mid-Atlantic.