Do I have to stop the turbine or take it down in very windy weather?

No, Proven Wind Turbines have a patented blade mechanism which means that they never exceed their design rotation speed. This means that they can run through the most severe weather without damage, and, unlike some wind turbines which have to face out of the wind, they go on producing full power output. There must be nothing more annoying than having your turbine furled out of the wind in a good blow! Scotland is the windiest country in Europe and most of our machines have been through >100 m.p.h. gales (160 k.p.h.). We have also had two recorded events of 150 m.p.h. (240 k.p.h.) which is in the ‘hurricane’ range.

At what wind speed will my wind generator start producing electricity?

Our wind generators start turning and producing electricity in just over a 5 mph wind. The energy available in the wind rises dramatically with windspeed - most of your power will come from periods when the wind is over 10 mph.

Do I need to have an energy storage system?

Only if you are not connected to the national grid

Are Proven Wind Turbines noisy?

No, they are specially designed to be suitable for installation close to people's dwellings. Proven Wind Turbines include special features to keep noise to a minimum. First  the turbines work at low rpm - this is very important. The speed of the blade tips is the most important thing for wind noise - Proven Wind Turbines operate at around half the tip speed of some other turbines on the market. Second, there is no gear box only a direct drive shaft to an electrical generator with no touching parts. Third, the blade tips have been specially shaped to reduce noise. The only noise from our turbines is the light swishing produced from the blade tips.

dB(A) noise levels (decibels) are published on our spec sheets.

Can I connect my windmill direct to the electricity grid network?

Yes, the Windy Boy Inverter developed by Proven and inverter manufacturer SMA allows you to connect direct to the grid. You have to get a) a connection agreement b) a commercial agreement set up with your electricity company. A Proven Authorised Dealer would normally handle (a) for you as part of the install and commission tasks. (b) is for you to shop around and choose the best deal available.

How does the Proven Direct Heating System Work?

Wind is a fluctuating resource. In order to get a smooth and useful output of heat we direct turbine output straight into electrical storage (or direct) heaters which then feed your house as heat is needed. The wind turbine controller includes an automatic switch-over which can be used to direct heat to two different outlets with a thermostat trigger. In a domestic situation these are often connected up to water heating with a temperature switchover to space heating.

In a UK climate, most of the wind is available during winter when heating is also a priority. Of course, most buildings lose (need) more heat when it is windy. There are always periods when heating is required but there is no wind - another source of heating is needed for these periods.

How does the Proven Grid Connect Inverter System Work?

At last you can plug your wind turbine directly into the grid! No batteries are needed!

A Proven grid connect inverter package converts raw power output by the wind turbine into electricity that is synchronized to the grid and is fed directly into the house or business fuse board.

A connection agreement is required with the electricity company - this will normally be applied for you by your installer or dealer.

During periods of windy weather you might produce more power than you are using - in this case power will be exported to the grid. On the other hand if you are using more than the turbine is producing at any particular instant, the extra is drawn from the grid as normal.

For sites that have a high baseload (usage of electricity), the turbine will never export to the grid and all the power will be used on site. In this case a simple connection agreement is all that is needed.

For installations that will export a significant proportion of the electricity produced by the turbine to be exported then it is best to enter into an agreement with an electricity supplier so you can get paid for the exported units.

What is a power inverter?

See our inverter fact sheet

What type of batteries do you use? How long will they last?

They are usually lead-acid deep-cycle cells quite different from automotive batteries. Lifetime is dependent on plate design but typically 6-15 years. For more information see our energy storage page.

How does the patented Proven flexible blade system work?

You can take two approaches to building a rotor capable of withstanding hurricane force winds. The first is to build it big and heavy enough to resist the huge forces involved - this rotor will proabably be quite inefficient at low wind speed and very expensive to build! The second, as pioneered by Proven is to use a flexible rotor which, like a tree in a storm, gives a little to reduce the mechanical forces exerted. See more about our blade technology.

What should I be looking for?

The first thing you should look for is build quality. Corrosion protection and extensive use of stainless steel components are just as important as the robustness of the overall design in contributing to many happy years of wind harvesting.

Second you need an efficient rotor, preferably designed to run at low rpm for good noise performance. The rotor should include at least one mechanism for self-protection in extreme weather conditions: there is over a thousand times the energy available for capture in a gale compared to a light breeze. Ideally the rotor blades should have variable pitch (just like the >500kW wind farm machines) with a coarse pitch for excellent start-up in light winds moving to a finer setting for efficient energy capture in a good blow.

Two bladed wind turbines rotate about 40% faster and are, in general. more vibration prone than their three bladed counter parts. Two bladed machines are not recommended for extremely turbulent sites since they can ‘whip round’ or yaw 180° suddenly due to a small vertical moment of inertia when the blades are vertical, often with disastrous results. Most small wind turbine manufacturers agree that 3 blades is the optimum number when aerodynamic and inertial forces are taken into account. Lower rotation speed and the associated lower forces are a distinct advantage in terms of machine longevity: this is true of all rotating machines!

Multi-blade rotors (as seen on mechanical wind pumps Western films) are designed to give very high starting torque needed to start the mechanical pump but are quite inefficient once moving since each blade passes through the “wake” of the blade in front. Modern designs with two or three blades will harvest much more of the energy passing through the ‘swept area’ of the rotor than either multi-blade or sail-blade designs.

The challenge to build a high-performance generator suitable for a small wind turbine is not a trivial one. Consider the initial specification. The generator should be compact, direct-drive (i.e. no gear box which in turn guarantees low maintenance and quiet operation) and have an excellent efficiency for mechanical to electrical energy conversion over the entire range of operating speeds. Serious wind turbine manufacturers nearly all use permanent magnet single or three phase generators.

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