New Clean Energy: Tornado Power

A retired engineer from Sarnia, Ontario, Louis Michaud, has spent the past four decades of his life studying the possibility of creating man-made tornadoes from industrial waste heat so that their energy can be harnessed for clean electricity generation. More recently, Louis Michaud has formed a company called AVEtec Energy, filed and obtained patents, and has partnered up with the University of Western Ontario's wind-tunnel lab to study small prototypes and do computer simulations of his "vortex engine" process. He's also managed to raise some early research funding from the Ontario Centres of Excellence and now faces his biggest challenge yet: convincing private investors to fund a large-scale working pilot plant.

It may sound like a whacky, out-there idea, but the experts I spoke with for the feature don't doubt the technical possibility of creating a man-made tornado. After all, the principles of convection are pretty straightforward. Heat rises when you've got a certain temperature differential, and as it rises it swirls -- kind of the reverse of what you see when water goes down a drain. AVEtec's pitch might raise eyebrows, but many are taking it seriously. For example, its advisory board consists of climate experts from Oxford, Cambridge and MIT, including MIT professor and well-respected hurricane expert Kerry Emanuel.

Mechanical energy is produced when heat is carried upward by convection in the atmosphere. A process for producing a tornado-like vortex and concentrating mechanical energy where it can be captured is proposed. The existence of tornadoes proves that low intensity solar radiation can produce concentrated mechanical energy. It should be possible to control a naturally occurring process. Controlling where mechanical energy is produced in the atmosphere offers the possibility of harnessing solar energy without having to use solar collectors.

The Atmospheric Vortex Engine (AVE) is a process for capturing the energy produced when heat is carried upward by convection in the atmosphere. The process is protected by patent applications and could become a major source of electrical energy. The unit cost of electrical energy produced with an AVE could be half the cost of the next most economical alternative.

A vortex engine consists of a cylindrical wall open at the top and with tangential air entries around the base. Heating the air within the wall using a temporary heat source such as steam starts the vortex. The heat required to sustain the vortex once established can be the natural heat content of warm humid air or can be provided in cooling towers located outside of the cylindrical wall and upstream of the deflectors. The continuous heat source for the peripheral heat exchanger can be waste industrial heat or warm seawater. Restricting the flow of air upstream of the deflectors regulates the intensity of the vortex. The vortex can be stopped by restricting the airflow to deflectors with direct orientation and by opening the airflow to deflectors with reverse orientation. The electrical energy is produced in turbo-expanders located upstream of the tangential air inlets. The pressure at the base of the vortex is less than ambient pressure because of the density of the rising air is less than the density of ambient air at the same level. The outlet pressure of the turbo-expanders is sub-atmospheric because they exhaust into the vortex.

The Atmospheric Vortex Engine has the same thermodynamic basis as the solar chimney. The physical tube of the solar chimney is replaced by centrifugal force in the vortex and the atmospheric boundary layer acts as the solar collector. The AVE needs neither the collector nor the high chimney. The efficiency of the solar chimney is proportional to its height which is limited by practical considerations, but a vortex can extend much higher than a physical chimney. The cylindrical wall could have a diameter of 200 m and a height of 100 m; the vortex could be 50 m in diameter at its base and extend up to the tropopause. Each AVE could generate 50 to 500 MW of electrical power.