Aspen has unique expertise in assessing the visual and thermal effects of plumes in the atmosphere. Aspen has conducted visible water vapor and/or thermal plume modeling analyses for over 60 power plant projects, including several thermal solar and geothermal power plant projects. Aspen predominately uses the following models/methods to complete these analyses:
Visible Water Vapor Plume Analysis
- Combustion Stack Visible Plume (CSVP) model
- Seasonal Annual Cooling Tower Impact (SACTI2) model
Thermal Plume Analysis
- Spillane Method calm wind thermal plume calculations
- MITRE Exhaust Plume Analyzer
Visible water vapor plume analyses can be used to aid the assessment of aesthetic impacts of water vapor plumes, and potential traffic impacts. Water vapor plumes can impact both ground traffic (ground fogging effects), or obscure air traffic visibility if plume sources are located near airports. Other related cooling tower plume modeling services include the assessment of ground icing (a.k.a. rime icing), plume shadowing, and salt deposition. The assessment of water vapor plume formation requires a keen understanding of the types of exhausts that can cause large water vapor plumes, including the ability to perform heat and material balances to create accurate plume model inputs, as well as a clear understanding of psychrometric principles.
Thermal plume analyses can be used to assess air traffic safety issues related to large thermal plume sources. The highest potential for safety impacts are for thermal plume sources near airports with a large amount of general aviation aircraft use. Other areas with low-flying small aircraft, such as areas with crop dusting, can also be impacted by large thermal plume sources. Plume modeling methods can evaluate the worst-case calm wind condition vertical velocity impacts (Spillane Method), or provide probabilities of severe turbulence or upset on different aircraft body types (MITRE Exhaust Plume Analyzer).
Aspen has assisted, and continues to assist, the California Energy Commission in evaluating different modeling techniques for visible water vapor plume modeling and thermal plume modeling. As part of this effort, Aspen has created and maintains updates for the Energy Commission’s Plume Modeling Training Course manual, and Aspen has provided two separate plume modeling method training sessions for Energy Commission staff.
