Comparative Emergy Synthesis of a Theoretical Offshore Wind Farm for Jacksonville, Florida

Wind power is currently the fastest growing renewable energy application in the United States. Many regions, however, such as the state of Florida, do not have high enough average wind speeds for wind power to be economically feasible. Nevertheless, Florida's extensive coastline may present the opportunity for implementing offshore wind technology. Offshore winds are typically stronger due to the lack of obstructions over open water, thus qualifying sections of the coastline as potentially desirable wind farm locations. An emergy synthesis was conducted to compare a theoretical offshore wind farm for Jacksonville, Florida to the following fossil fuel units currently operating at Jacksonville Electric Authority: a purely coal-fired steam turbine based on Plant Scherer; a steam turbine fueled by a mix of coal and petroleum coke based on St. Johns River Power Park; and a natural gas combined-cycle unit based on Brandy Branch. The emergy analysis determined that the wind farm had an emergy yield ratio of 2.0, compared to 19 for the coal system, 14.5 for the coal-mix system, and 11.3 for the natural gas system. The wind farm’s environmental loading ratio was found to be five orders of magnitude lower than the conventional systems, with a value of 0.96. Similarly, the emergy index of sustainability for the wind farm was found to have an advantageously higher value of 2, while the fossil fired systems were found to be on the order of 10 to 10.