The Ettridge Wind Turbine

A New Generation Environmentally friendly Wind Turbine



  1. The most efficient conversion of wind power to  rotary mechanical motion.
  2. Simple low cost construction.
  3. Smaller size than comparable propeller type wind generators.
  4. Multi uses, including automobile applications.
  5. Low environmental visual profile.
  6. No high towers needed, can be positioned at ground  height, or roof height.
  7. Can be screened to ensure no harm to wildlife and protected birds.
  8. Easy Maintenance at ground level.
  9. No high surface speeds and excessive noise.


I would like to introduce you to an Improved Rotary Wind Powered Turbine ( Savonius Rotor ) that I have invented. We are all familiar with the propeller type of wind generator, and most would know of the rotary air ventilators used on the top of vans, commercial vehicles and factories, the rotary ventilator has been condemned to low torque applications up to now, but with this improved rotary wind powered turbine, that is all about to change.

The common Wind Generator is propeller driven, mounted on a tall tower, but due to their visual impact, many planning authorities are refusing planning approval, pushing proposed wind farm developments out into the country, and often away from electricity connectors, adding substantial costs to the wind farm developer.

The Improved Rotary Wind Powered Turbine is a low visual impact alternative, which does not require to be mounted on a high tower, this is a down to earth installation which delivers high efficiency, uses simple gearing if needed (depends on average wind speeds ) and low cost installation and maintenance. A real alternative wind farm generator worth considering.   

So, what is new, and how does it work ?

The problem with the current Savonius type wind turbines is the fact that the blades are only driven by the wind for approximately 120 degrees of one rotation, that is from the direction of the oncoming wind to about 120 degree from the center, the remaining 240 degrees, the blades are actually using power, and have to be driven into the wind. The solution that I came up with was to allow the normal operation for the 120 degrees of the turn, and for the remaining 240 degrees to place a shield, or skirt to cover the blades in the area that they normally would need to be driven into the oncoming wind, and by using overhead air scoops, directed the air above the rotor down into the tunnel created by the rotor and wind shield. This has the effect that the blades on the rotating turbine are driven for the full 360 degrees, greatly improving low wind speed start up efficiency, and by rotating the skirt and scoops effectively feathering the rotor in high wind speeds. The wind shield also can be moved, to ensure the wind scoops are facing the direction of the oncoming wind, either by a wind tail or mechanical means.

I have attached a simple animation to show how it works.

I am looking for financial assistance to build a demonstration unit, if your company would like to know more, or can be of assistance, please contact John Patrick Ettridge at:

The Future

The World needs Salt Free Water


Wind energy can deliver the answer, it is quite simple, the oceans and seas of the World cover about 70 percent of the Earth's surface, and are made up of salt water, all we have to do is extract the salt from the sea water, and we have all the fresh water that we require, for drinking and agriculture. There are several known ways to remove the salt of which Distillation ( the evaporation and then condensing of water to obtain purified water ) and Reverse Osmosis ( by forcing the salt water through a membrane to extract the salt ) are the most common methods. Both use large amounts of electrical energy to be effective. The simple answer is to use a dedicated wind farm situated close to the ocean, to provide the electrical energy, the ocean provides the water. The fresh water produced is then stored in a reservoir, and pumped to where it is needed.

One of the problems with Wind energy is that it is not working all the time, and on demand twenty four hours every day, but for water desalinization it is not necessary that it be working on demand, it would be sufficient that it is working three quarters of the time. With 365 days in a year, if it was working 270 days a year that would be acceptable.  

The constituents of seawater include dissolved inorganic substances such as salts. Sodium and chloride ions predominate in seawater; together they form more than 85 percent by weight of the total amount of dissolved salts. The total salt content may vary, because seawater can be diluted by additions of precipitation in the form of rain or snow, fresh river water, or water from melting icebergs. Seawater may become more saline in various parts of the world because of natural evaporation of water.

Throughout the world, hundreds of desalination units, producing from a few thousand to 10,000,000 or more gallons per day, already are in operation. In general, the desalination plants in production are in areas where the population has outstripped the onshore water supply and where high-cost desalinated water can be afforded. This situation tends to arise in coastal desert areas, or on densely populated islands because the costs of pumping water through pipelines to interior areas would add prohibitively to the basic cost, at the sites of desalination, unless low cost renewable energy was used.

A population usually can afford to pay about ten times as much for water for domestic purposes than it does for agricultural water. Proposals for large-scale Wind Farm Generation facilities, when constructed, promise to lower the cost of desalinated water to 10 cents to 30 cents per 1,000 gallons, at the desalination sites, which is a price that all domestic users, most industries, and a few agricultural enterprises can afford.

At the present time, the bulk of the water produced from seawater is produced by some form of evaporation and condensation or by reverse osmosis. Although the principle of this technique is quite simple, the mechanics of achieving high efficiencies can become quite complicated. Superheated water and multiple evaporation and condensation units, operating at varying temperatures and pressures, are employed in a number of these facilities. The choice of construction materials is quite important, because the brines produced in extracting pure water can be corrosive. With the reverse osmosis, it is the replacement and maintenance of the membranes.

Other processes under consideration as potential economic methods of desalting seawater are freezing, ionic processes, electrodialysis, and techniques that change the physical or chemical properties of water itself so that it can be separated from the salts in seawater. In the future, it can be expected that the ocean will become an increasingly important source of freshwater. If production and transportation costs can be lowered sufficiently, it may be possible to produce freshwater to irrigate large areas of agricultural land in many parts of the world.

FAQ (frequently asked questions)

The most asked question is how it works?

Answer: The Ettridge Wind Generator works on a spinnaker or sail principle, not as the propeller wind generators, which use an aero foil principle. We would all have seen sailing boats or yachts moving in the same direction as the wind, with a large sail puffed out to catch as much wind as possible. They can only use the spinnaker while traveling in the same direction as the wind. The normal air extractor, which is fitted to vans etc. only has two blades adjacent to one another, and relies on the fact that the curve in the blade means that one side offers more wind resistance than the other side. If both blades were flat and the same size, it would not move at all. One side of the blade is scooped, and catches the oncoming wind, while on the other side, the scoop is reversed, and deflects the oncoming wind. However it does use energy from the other side scoop to achieve this. It effectively has a power stroke for 120 degrees of one turn, while the returning scoop uses energy to be driven into the oncoming wind for 240 degrees of one turn. With the Ettridge Wind Turbine, a wind shield is positioned in the 240 degrees area, to prevent the oncoming wind acting on the turbine blade. Although this would prevent the oncoming wind acting on the returning turbine blade, the blade would be pushing the air in front of it which is trapped in the tunnel formed by the turbine blade and wind shield; so it would still be using energy in the return direction. To overcome this problem, a wind scoop is fitted above the turbine, and at the correct place, the wind is directed down into the tunnel, and forces the turbine to rotate in the direction of the wind. This means  that both turbine blades are producing a power stroke, and at no time are they using up energy to be driven. It also means that more turbine blades can be fitted to give a larger surface area to resist the wind movement, providing more power to the turbine shaft. It has the same effect as the wind direction changing, and following a circular path for the sailing boat. The usual propeller used on a wind generator has two or three blades, and does not have a large surface area exposed to the wind.

Is Wind energy another form of Solar Energy?

Answer: Yes, Wind is produced by the sun heating a land mass, and the heat from the land is absorbed by the surrounding air. When the air temperature reaches a certain temperature, it begins to rise quickly upwards, this results in a low pressure area at ground level, and a higher pressure area above ground level. Remember, hot air rises, cold air falls, it is this movement of air from one place to another that we call convection currents or wind. Air naturally moves from high pressure areas to low pressure areas, trying to equalize the air pressure. Areas of the Earth closer to the sun, such as the equator, become warm quicker than areas further away, such as the poles. As the air moves over the warm areas and rises, cooler air from surrounding areas rushes in to fill the space left by the rising air, thereby creating surface winds or air movement. Due to elevation, topography, location and surface ruggedness, some locations experience more wind than other locations. Winds occur both in the day time and at night.

Solar radiation is subject to the same conditions as for winds, but has a much shorter time frame. For solar radiation to occur, it must be day time or daylight hours, there is no solar radiation at night. Solar radiation is not subject to convection currents.

How is wind used to create electricity?

Answer: The rotation movement of the turbine drives a generator, either by direct drive or through gearing, to produce electricity. This electricity can be used on-site in an automobile, for domestic uses in a home, or commercial applications in a business, farm, etc. or can be connected in to an electrical grid for transmission to others who require it.

How does the cost of wind generation compare with Photo voltaics and Solar Thermal ?

Answer:  Both Wind and Photo voltaics ( solar cells, usually in sheets which convert sunlight directly into electricity ) are in commercial production, while Solar thermals ( directing the suns rays by the use of mirrors on to a central heating element, to turn water to steam which is used to drive a turbine and generator ) is still in a  prototype stage with some large commercial size installations proposed. At this stage, Photo voltaics installed cost approximately $8 / watt, which it is hoped to reduce to $3 in 2010. They are typically used in Suburban sites, and naturally depend on location, intensity of sun available and duration of sunlight. Solar thermal is still in the demo stage, with the expected installed costs around $10 / watt, and is expected to be used mainly by large commercial companies, and again depend on location, intensity of sun available and duration of sun light. Wind energy for small installations is about $3.30 / watt but is expected to reduce to $1.60 by 2010; large commercial units are even lower and depending on size, can be installed in Suburban or Rural areas, and located in an area with average wind movement above 8 mph is desirable.

Does the Ettridge Wind Turbine have to be mounted on a tower ?

Answer:  The Ettridge Wind Turbine is the only wind turbine that can operate at ground level, simply because it works on a sail, spinnaker principle, and as we all know sailing ships and yachts work at sea level. Naturally the clean air movement and constant direction of the wind is desirable, and a domestic unit installed on the roof of a house would be better than ground level, provided there are no tall trees planted around the house. A commercial unit located near the top or on the top of a hill would have no more visual impact than a shed or water tank. Painted in an appropriate color ( green or light blue ) it would be difficult to see. The small propeller wind turbines are mounted at the top of masts or towers, with a minimum height of 40 feet =(12 meters) and can be much higher, while commercial units, have towers 80-130 ft =( 24-40 meters).

Is the foot print ( area of the base, or mounting ) as large as a propeller wind generator ?

Answer: If you compare a small domestic wind generator on a 40 foot mast, and include the area taken by the retaining wires, the answer is No. For a domestic application, it needs about the same size as a evaporative water cooled air conditioner, which is much smaller in area than the 40 ft mast plus retaining wires. If you compare it to a commercial unit with a  80-130ft mast, it would be about the same size, but only 20-30ft high.

How much noise does the Ettridge Wind turbine make compared to propeller type wind generators ?

Answer: How much noise does a sail or spinnaker make ? There are no high surface speeds. The blades in the Ettridge Wind Turbine only move the speed of the wind or slower, unlike a propeller tip which can approach the speed of sound. I have read about people who installed a small domestic wind generator close to their house, and described the sound " like a hurricane fighter plane about to land on the house " in strong winds. That is why most domestic installations are as far away from the house as possible. The noise level using the Ettridge Wind Turbine is negligible, about the same as the surrounding wind. 

How is the Generator attached to the Ettridge Wind Turbine ?

Answer:  The Ettridge Wind Generator can have a Gemini Electric Generator incorporated in the base of the turbine, in line with the main shaft.  The Gemini Electric Generator website is :

It is possible to run a gearbox off the base to step up the speed if using a conventional alternator.

How does the cost compare to a conventional propeller wind generator ?

Answer: The cost of a domestic installation of the Ettridge Wind generator would be less than the total cost of an equivalent propeller wind generator, especially when the cost of the tower or mast is included. The larger the unit, the greater the difference in cost, with the Ettridge Wind Turbine being the lower cost.

Is there much maintenance with the Ettridge Wind Turbine ?

Answer: There is very low maintenance with the Ettridge Wind turbine, and provided the bearings on the rotor shaft are well lubricated, and they require about the same attention as the wheel bearings on an automobile. Because the Ettridge Wind Turbine can be situated at ground level, naturally any debris from trees or vegetation needs to be kept low or clear. If vegetation builds up, apart from restricting the wind, solid vegetation could obstruct the rotor and damage the blades. It would be fairly obvious that the area around the turbine needs to be cleared or kept very short. Ideally the area would be fenced or the area on which the base of the turbine sits on,  should be raised to prevent domestic animals getting near the turbine blades. 


What's New

The Ettridge Wind Turbine is the only Wind Turbine that can be scaled down to be suitable for use with electric powered vehicles. One of the problems with wind generators is that when there is no wind, they do not work. But of course even if there is no wind, and a vehicle is traveling at 60 km/h, then there is a 60 km/h wind or air movement over the roof of the vehicle, or through the front of the vehicle, where the radiator would have been placed, in an internal combustion powered vehicle.

In the animation above, the black arrows represent the wind at the lower level moving the turbine blades in the uncovered portion of the wind shield which is attached to the wind scoop, that is about 120 degrees of rotation.

The  red arrows represent the wind at the high level in the wind scoop and the tunnel formed by the wind shield and turbine blades, the remaining 240 degrees of rotation.

Naturally if the Ettridge Wind Turbine is fixed in a vehicle there is no need for the wind scoop and wind shield to be able to rotate, as the direction of the wind will always be from the front of the vehicle.


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