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Micro-hydroelectric Power from Fog Fences

Fog fences have been used for decades to collect the water droplets from dew and fog after which the moisture is sent to storage systems via piping systems. These fences are typically located at higher elevations near coastal regions where moisture is carried in by winds that blow over a cold ocean current during the early morning hours. The circulation of air from sea to land results from a landmass warming at a faster rate after sunrise than seawater in an adjacent ocean. The result is that moisture laden cool air will slowly blow across the cooler sea to the land after sunrise each day.

There are locations where high mountains are located right next to an ocean coast. Some of these locations include the West Coasts of Chile and Peru, the South Island of New Zealand and the southern tip of Africa. Dr Theodore Schumann who was South Africa's chief meteorologist after World War 2 proposed that an electrified fog fence built to a height of 150-feet be installed on top of Table Mountain that is located next to the City of Cape Town. He suggested that fence carry up to 50-KVA of power at low amperage. His research indicated that some 30,000,000-gallons of fresh water per day (2890-lb/sec) could have been obtained from moisture laden winds that blew over the cold South Atlantic Ocean and over Table Mountain (elev: 2500-ft to 3400-ft).

Modern technology could greatly increase the overall height of electrified fog fences. The higher fences could be supplied with some 50-KVA at 10-amperes (500-Kw) of electric power generated by a large windmill or by hydroelectric power. A flow rate of 2890-lb/sec of water and a vertical height of 1000-ft would calculate to 3100-Kw of power at a conversion efficiency of 80%. The net output for a fog fence of 150-feet in height will be over 2800-Kw of power. Net output could be increased to over 8600-Kw for a fog fence of 600-feet in height. Schumann's concept of using an electrified fence to obtain water (and electric power) from fog that drifts over a high mountain could be modified for use elsewhere around the world.

It may become possible for researchers to modify fog fence technology for use in locations where winds blow over warm expanses of water then carry moisture laden winds over land. Such is the case in the Eastern USA where summer winds blow over the Gulf of Mexico and carry moisture laden air into the Eastern and Northeastern USA that is synonymous with high summer humidity. Some of this intensely humid air blows directly over both the Appalachian Mountains and also the Allegheny Mountains in the Eastern USA. It may be possible to install a series of specially modified electrified fog fences at numerous locations in both these mountain ranges to collect water early every morning and enable micro-hydroelectric power to be generated at numerous locations.

Up to 70,000-gallons of fresh water per minute could be collected each summer morning by electrified fog fences. The water and power may serve the needs of nearby local communities. It may be possible for the fog fences to reduce the intense humidity in the summer air that would subsequently drift toward large population centers such as Washington, Baltimore, Philadelphia, New York and Boston. A reduction in summer humidity in these centers could enable a segment of the local populations to experience less discomfort during hot summer weather. This segment may subsequently have less need for air conditioning in their homes during part of the hot summer. Their collective choice may subsequently help conserve energy during times of peak power demand.

Some innovative modifications may need to be incorporated into electrified fog fence technology to enable it to function in the kind of hot and humid weather that exists in America's Appalachian mountain range during the summer months. The technology would also need to be designed to withstand the kinds of severe winter blizzard and ice conditions that are common in the Northeastern America winters. The effectiveness of the technology at removing large amounts of moisture from intensely humid summer air during early morning hours would be high priority. That effectiveness would determine the long-term value of the technology to the regions near to their point of installation.

Fog fence technology is well proven along the West Coast of Latin America where it is used to collect water from moisture-laden winds that blow inland from the cool South Pacific Ocean. There is also a high amount of summer rainfall that occurs in the mountains of southern Mexico and of Central America as well as over the Guiana Highlands of Venezuela suggests. The moisture-laden summer winds that prevail over these aforementioned highland areas first blew over warm water in the Gulf of Mexico where they collected the moisture. That precipitation occurred in these regions indicates that electrified fog fences may actually work as intended in the Appalachian Mountains.


Content Discussion

Berol Robinson's picture
Berol Robinson
A propos, a friend of mine, raised i as a country boy, used to say "It is a wise sparrow that knows how to find the grains of oats in horse manure."

Berol Robinson

Lee Fellows's picture
Lee Fellows
There was an article in Popular Science or Popular Mechanics circa 1970, and a "power fence" such as this. The primary product was electrical energy derived from moist winds. Pity Seattle hasn't built one on the coast.

L. Fellows

Charlotte Wolter's picture
Charlotte Wolter
The ideas are interesting, but I have to echo the earlier comment that it would be helpful to have metrics of power and water produced. The one thing that concerns me is the comment about reducing the humidity in the northeastern United States. That would mean major climate change. The lush forests of the eastern United Statesare an important resource. Also, few would not look forward to a hike on the Appalacihian Trail if it included numerous vistas of fog fences. Luckily, it seems unlikely that fog fences could reduce the humidity of the Northeast significantly, unless, of course, we are very very greedy with the technology.

C. Wolter