Switching to Switchgrass: Pathways and consequences of bioenergy switchgrass entering the Midwestern landscape

Abstract

The US has the ambitious goal of producing 60 billion liters of cellulosic biofuel by 2022. Researchers and US Federal Agencies have identified switchgrass (Panicum virgatum L.) as a potential feedstock for next generation biofuels to help meet this goal because of its excellent agronomic and environmental characteristics. With national policy supporting the development of a switchgrass to bioenergy industry two key questions arise: 1) Under what economic and political conditions will switchgrass enter the landscape? 2) Where on the landscape will switchgrass be cultivated given varying economic and political conditions? The goal of this dissertation is to answer these questions by analyzing the adoption of switchgrass across the upper Midwestern US at a high spatial resolution (30m) under varying economic conditions. In the first chapter, I model switchgrass yields at a high resolution and find considerable variability in switchgrass yields across space, scale, time, and nitrogen management. Then in the second chapter, I use the spatial results from chapter one to challenge the assumption that low-input (unmanaged) switchgrass systems cannot compete economically with high-input (managed) switchgrass systems. Finally, in the third chapter, I evaluate the economic and land quality conditions required for switchgrass to be competitive with a corn/soy rotation. I find that switchgrass can displace low-yielding corn/soy on environmentally sensitive land but, to be competitive, it requires economic support through payments for ecosystem services equal to $360 ha-1. With a total expenditure of $4.3 billion annually for ecosystem services, switchgrass could displace corn/soy on 12.2 million hectares of environmentally sensitive land and increase ethanol production above that from the existing corn by 20 billion liters. Thus, ecosystem services can be an effective means of meeting both bioenergy and environmental goals. Taking the three chapters in aggregate it is apparent that switchgrass faces many challenges before it will be adopted on the landscape and it is unlikely it will be adopted under traditional market pricing. However, switchgrass does have considerable potential to help meet the US’s bioenergy and environmental goals through new mechanisms, such as payments for ecosystem services potentially coupled with low-input management systems.