An atmospheric modeling system designed to create simulated wind climatologies to support wind-generated power production

The concept of generating electrical power from the energy of the wind has received renewed interest during the last several years. This has been a result of (1) increased interest in reducing the emission of greenhouse gases by traditional electric generation plants fueled by oil, coal or natural gas; (2) major changes in the economic and organizational structure of the electric utility industry which allow customers who have a choice in the supplier of their electricity and how it is generated; and (3) improvements in wind power technology that has reduced the cost of generation to a level that is competitive with the traditional methods of generating electricity. Within the last year the total US capacity has doubled to approximately 2500 megawatts. In order to achieve optimal wind power generation and use, the wind power industry needs to properly site the wind power generation facilities (i.e. arrays of wind turbines). To achieve this, there is a need for high resolution spatial maps of the wind climatology. In order to address this and other meteorological needs of the wind power industry, MESO, Inc. has developed a dynamical-statistical modeling system called FOREWIND.

FOREWIND has two major components: a high resolution boundary model and an adaptive statistics model. The dynamical model is based upon the basic physical principles of conservation of mass, momentum and energy and includes a Turbulent Kinetic Energy (TKE) boundary layer submodel. FOREWIND is designed to simulate the lowest 2-3 km of the atmosphere over a limited horizontal domain with a horizontal resolution between 1 and 5 km. The conditions at the vertical and lateral boundaries are specified from an external source. The FOREWIND modeling system is capable of operating in two modes: a climatological mode and a forecast mode. When in the climatological mode FOREWIND is used as a non-real-time application, allowing the model to utilize a grid point analysis of observational data for both the initialization and boundary condition specification. The modeling system has the capability to ingest external analysis datasets such as those in the NCAR/NCEP reanalysis database, or to generate its own grid point analysis from raw observational data.

Climatological wind maps are constructed by running a large sample of historical cases with FOREWIND and then blending the simulated data with the quality-controlled observational data to construct the final wind climatology. To assess the quality of the wind maps, a series of validation experiments have been conducted at a number of wind energy-related sites with extensive wind measurement instrumentation in Pennsylvania, New Hampshire, Massachusetts, Minnesota, California and Southeast Asia. Preliminary results indicate that the magnitude of the simulated wind climatology errors are highly correlated to the site which suggests that local factors (e.g. roughness, exposure etc.) are a major factor in wind simulation errors. In order to account for these factors which are below the grid scale of the dynamical model, an adaptive statistics module is used to refine the output of the dynamical model for a particular point. A description of the modeling system and a variety of validation results will be presented at the conference.