Infrastructure Impacts of Iowa's Renewable Energy

This paper investigates the physical and fiscal impacts of Iowa's existing biofuel plants and wind power industries. A four-county cluster in northern Iowa and a two-county cluster in southern Iowa were identified through a local agency survey as having a large number of diverse facilities and were selected for analysis of traffic and physical impact. The large-truck traffic patterns on Iowa's secondary and local roads from 2002 to 2008 were analyzed and associated with the pavement condition and county maintenance expenditures. A trend of increased maintenance costs in the year after a biofuel plant became operational as well as during the construction period was observed. Large-truck traffic also increased dramatically during the construction period and then dropped after the plant became operational, but not to the levels before the plant's construction. The major road damage associated with wind farms occurred during construction activities and predominantly on gravel roads. Face-to-face interviews with county engineers were conducted to validate the observed trends and discuss the limitations of the data. Finally, with an expanded sample of 24 counties, one-way panel data regression models were developed to estimate pavement condition and maintenance costs as a function of vehicle miles traveled, plant capacity and years of operation, corn and soybean production, and soil and environmental conditions.