Fig 1.
Habitat range maps and HCP locations (from this study).
The colored areas identify the current ranges of four common bat species (Indiana bat, Northern long-eared bat, Tricolored bat and Little brown bat), and the locations of each of the HCPs analyzed in this study. Base map credit: ArcGIS, ESRI, Garmin, FAO, NOAA, EPA. Map and data for wind turbines are publicly available from U.S. Wind Turbine Database, provided by the U.S. Geological Survey, American Clean Power Association, and Lawrence Berkeley National Laboratory via https://energy.usgs.gov/uswtdb. Bat habitat range maps are publicly available from U.S. Fish and Wildlife Service, Department of the Interior (https://www.fws.gov/species).
Table 1.
The 25 project-scale Habitat Conservation Plans included for this bat-wind energy cost analysis.
Fig 2.
Example Output of GLM (General Linear Model) The equation can be read as “variable X adds millions of dollars to the total cost (or number of bats to total bat take) for each unit increase in the variable.”
“Intercept” is a corrective term: if all variables were found to be significant, then this value would be 0. As an example, an approximate cost estimate for a 25-year project built in Region 5, after 2019, with a bat take of three (3), and 300 MW output from 100 turbines would be ~ $6,300,000 based on the following equation.
Fig 3.
a. Correleogram of variables related to total and mitigation costs. b. Correleogram of variables related to fatality monitoring costs.
Table 2.
Medians and confidence intervals for all variables and across all categories and between regions (R3 and R5) with highlighted variables that are significantly different. The data set of HCPs in R5 was too small to calculate median confidence interval.
Fig 4.
Proportions of total reported costs by category.