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Wind Farm Siting. Dennis Scanlin (Department of Technology) Xingong Li Chris Larson (Department of Geography & Planning) Appalachian State University. Multi-Criteria Evaluation (MCE). Evaluates a number of alternatives in the light of multiple criteria / factors.
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Wind Farm Siting Dennis Scanlin (Department of Technology) Xingong Li Chris Larson (Department of Geography & Planning) Appalachian State University
Multi-Criteria Evaluation (MCE) • Evaluates a number of alternatives in the light of multiple criteria / factors. • Factor scores of the alternatives • Factor weights • Relative importance of the factors • Ranking scores of the alternatives • Weighted combination of factors
Organizes factors into a tree structure • Innate model of operation of human mind • Helps complex decisions by decomposing the problem Analytic Hierarchy Process • Determines factor weights • Difficult to determine factor weights (numbers) directly • Derives weights by comparing the relative importance between two factors
AHP Factor Weights Determination • Factor relative importance pairwise comparison (9-point scale) • 1—equally importance • 3—moderately more importance • 5—strongly more importance • 7—very strongly more importance • 9—extremely more importance • The best weights fit into the pairwise comparisons.
Spatial Analytical Hierarchy Process • Wind farm siting • Find the best wind farm sites based on siting factors • Alternatives • Location—infinite • Divide the space into squares/cells (200m * 200m) • Evaluate each cell based on the siting factors
Preliminary Siting Factors • Accessibility to roads • Distance to primary roads • Distance to secondary roads • Distance to rural roads • Accessibility to transmission lines • Distance to 100K lines • Distance to 250K lines • Distance to above250K lines • Wind power (or wind speed) • Visibility • Viewshed size • # of people in viewshed
Siting Steps • Factor generation • Distance calculation • Visibility calculation • Factor standardization (0 – 100) • Each factor is a map layer • Factor weights determination by AHP • Final score • Weighted combination of factors • Exclusion areas
(Turbine: 50m; Observer: 1.5m; Visual distance: 20mi) Wind Turbine visibility--Viewshed
Wind Turbine Viewshed Size • Red—505km2 • Greed--805km2 • Blue--365km2 • Software tool developed to calculate viewshed size for each cell
Visibility Factor—Viewshed Size • Computational expensive • About 700,000 cells • Each cell requires 10 seconds • About 76 days • Parallel computing • 12 computers • Each computer runs two counties • About 55000 cells • 6 days • Succeed with 3000 cells but failed with 55,000 cells
2000 census block data Visibility Factor--# of People in Viewshed
Thanks! • Questions?
ArcMap GIS AHP GIS Using AHP in GIS • AHP is implemented as a software component • AHP is integrated with ArcMap GIS(ESRI, Inc.) as an extension