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The wind resource estimates were developed using MesoMap, a wind mapping system developed by TrueWind Solutions. MesoMap combines two models, MASS, a mesoscale atmospheric simulation model similar to a weather forecasting model, and WindMap, a simpler wind flow model. The results were validated by the National Renewable Energy Laboratory (NREL) and independent meteorologists using historical data. Wind speeds shown are estimated to be within about +/-5% accuracy, and wind power density values (which are related to the cube of the speed) are estimated to be within about +/-15% accuracy. This means that the actual wind speed should be within 5% of the predicted at two-thirds of the locations on the map, and should be within 10% of the actual at about 95% of the locations, assuming that the measurements are taken in well exposed areas, with minimal obstructions, and following wind industry measurement guidelines.
The two models work together, but at different scales. MASS operates on a spatial grid resolution of 2.6 km (1.6 miles), whereas WindMap operates on a resolution of 400 meters (1312 ft, or one-quarter mile), which is the final scale of the maps. While WindMap can simulate the acceleration of winds over small hills and ridges, many other terrain effects require the more sophisticated MASS. Such effects include channeling through valleys or passes (such as Judith Gap or Livingston Pass) and downslope flows (e.g., Blackfeet area). To the extent these effects are at work, the accuracy of the maps is limited by the spatial grid resolution of MASS. To be resolved completely, a terrain feature must be larger than about 3-4 grid cells. Therefore, for instance, a valley that is less than about 7-10 km wide will not be fully "seen" by the MASS model, and if there is any channeling through that gap, it will be underestimated or entirely missed in the map. Likewise, detailed aspects of a downslope flow, including its intensity and full extent, will not be resolved better than the scale of the MASS simulations.
Site feasibility studies should be conducted to confirm the map estimates, including direct measurement at turbine hub height according to wind energy industry standards. Weather deviations from long-term averages and local terrain effects may cause additional variations from the map estimates. Local site characteristics such as trees, buildings and other obstructions can significantly affect wind speed and turbine output estimates. Wind speeds can be reduced at up to four times the height of an obstruction and as far away as a mile or more. Small differences in wind speeds translate into large differences in turbine outputs.
Neither TrueWind Solutions nor any of the project sponsors (including NREL, BPA, Northwest SEED and NWCDC) make any guarantees or accept liability for the accuracy of the estimates presented here. Use of the maps and/or data for anything other than general information is solely at the risk of the user. TrueWind and project sponsors may not be held liable for any loss, damage or other consequence resulting form the use of the maps and/or data contained on these pages.
Please see Adjustments for Local Conditions and Accuracy of Wind Map Estimates for more information. By using this data, the user agrees that he or she has read the disclaimer statement above and agrees to assume all liability for using the data.
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