Understanding Wind Power

One concern when looking at alternative energy from a consumer perspective is the fact that the technology can seem unfamiliar. Everyone understands how fuel burns in an internal combustion engine, or how burning coal could fuel a power station. Solar power seems more alien than steam power, but we trust that it works.

Residential wind turbines are now far less conventional than solar energy. Depending on where you live, you might never have seen a commercial wind farm.

Fortunately, anyone paying attention in science high school classes will understand the principles behind wind turbines. Do you remember where we learnt about types of energy being transformed from one form to another? That energy cannot be destroyed, only converted into different forms?

We remember that chemical energy can turn into heat energy. Heat energy can be transformed into kinetic energy and so on.

Basic Mechanics:

Wind is a form of kinetic energy, and it turns the rotor blades of a turbine. The blades rotate a shaft, which spins a dynamo. Do you remember what dynamos are? To use the high school analogy, we turned copper wire around a frame in lots of coils. Then we put the coiled wire between magnets, spun it around and created enough electricity to turn on a light bulb!

Older readers will remember having dynamos on their bicycles. The Dynamo would touch the wheel, and spin as we cycled. This would light up the front and back bike lights without any need for batteries. Bicycle dynamo lights are still available nowadays, but we don’t see them often. What a great idea to combat battery waste though.

The laws of physics that we studied at school also influence the quality and efficiency of each turbine. For example, a lighter weight, more freely spinning blade will convert more wind energy into electricity because less will be wasted in turning the blade.

Spinning the Dynamo Faster

The main difference between an air turbine and the experiments that we did at school to generate electricity is the use of a gearbox. Wind turbines have gearboxes that speed up the rotation by up to a hundred times. When you see the rotors spinning slowly, realise that the dynamo/generator will be spinning far faster.

This video is helpful in understanding the mechanics:

Also, the laws of physics will affect other parts of the installation. Your choice of electrical wire that goes from the turbine into your home makes a big difference. If it’s too heavy duty, electricity will be lost along the wire through the impedance. (Impedance is the measure of opposition that an electrical circuit gives to a current when the voltage is applied).

Geography

It’s not just physics, but geography too. Did you know that the same wind turbine can be highly economical, or a complete waste of money? Just as in the real estate business, it’s all about the location, on different levels:

• Your site (city/state etc.) might be very windy, or not windy at all.
• Your property might be at a higher or lower elevation compared to the local area.
• Your Property might be in a valley, or behind city buildings in relation to the direction of the average prevailing wind.
• The height above ground makes a huge difference, regardless of other local factors. Building a tower might cost more, but make the project cost effective in the long run.

As you can see, many factors influence how well the turbine works for you. It’s tempting to focus on models and brand specifications or even ‘special deals’. Other people will watch YouTube videos of other people unpacking, installing and testing. Unless they live next door, these aren’t the best resources for you.

There’s no substitute for a quick refresher of high school physics. Some basic understanding of physics, geography and simple electrical circuits and safety factors will be worth it. Then you can make a better choice of turbine, equipment, installation and future servicing.