Citation:

Campbell, Dan AND L. Erban. A Reexamination of the Emergy Input to a System from the Wind. In Proceedings, Emergy Synthesis 9: Theory and Applications of the Emergy Methodology, Gainesville, Florida, January 07 - 09, 2016. Center for Environmental Policy, University of Florida, Gainsville, FL, 13-19, (2017).

Impact/Purpose:

This is a paper in the proceedings of Emergy Synthesis 9, thus it will be available online for those interested in this subject. The paper describes a new and more accurate way to estimate the wind energy and emergy input to any system. It also has a new calculation of the transformity of wind energy based on a general circulation model of the atmosphere. Since both calculations are new it is possible that they will have a significant impact on emergy researchers in the future. The fundamental equation of emergy analysis is: Emergy (sej) = Available energy (J) * Transformity (sej/J), where "sej" stands for solar emjoule, the unit of emergy, J stands for a joule, the unit of available energy and transformity is the factor relating the two measures with units sej/J.

Description:

The wind energy absorbed in the global boundary layer (GBL, 900 mb surface) is the basis for calculating the wind emergy input for any system on the Earth’s surface. Estimates of the wind emergy input to a system depend on the amount of wind energy dissipated, which can have a range of magnitudes for a given velocity depending on surface drag and atmospheric stability at the location and time period under study. In this study, we develop a method to consider this complexity in estimating the emergy input to a system from the wind. A new calculation of the transformity of the wind energy dissipated in the GBL (900 mb surface) based on general models of atmospheric circulation in the planetary boundary layer (PBL, 100 mb surface) is presented and expressed on the 12.0E+24 seJ y-1 geobiosphere baseline to complete the information needed to calculate the emergy input from the wind to the GBL of any system. The average transformity of wind energy dissipated in the GBL (below 900 mb) was 1241±650 sej J-1. The analysis showed that the transformity of the wind varies over the course of a year such that summer processes may require a different wind transformity than processes occurring with a winter or annual time boundary.

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