Wind energy can be produced anywhere in the world where the wind blows with a strong and consistent force. Windier locations produce more energy, which lowers the cost of producing electricity. Moderate to excellent wind resources are found in most regions of the United States and off the nation’s coasts in many areas. Wind resource maps available through the Wind Program can help individuals, communities, and developers determine whether the wind resource in a particular area is adequate for wind power.

Wind turbines have been used for millennia to convert the wind’s kinetic energy into mechanical energy. As early as 200 B.C., mechanical energy was used for specific tasks including grinding grain and pumping water. Nowadays, the kinetic energy contained in the air can be converted via a generator into electricity.

Much like solar PV installations, you can purchase a wind turbine to supply as much or as little electricity as you want. If you want to be fully dependant, you are going to need a larger turbine, or multiple smaller turbines. If you are simply looking to produce enough electricity for a light in your garden shed, you can get away with a very small turbine.

Below we look at the different types of wind turbine system you can install in your property.

BATTERYLESS GRID TIED SYSTEMS

Batteryless grid tied systems are the simplest, most effective and most environmentally friendly wind turbine systems. Their role is simple, to produce the most electricity possible to provide electricity for your home and also feed into the grid. Due to the availability of grants such as the feed-in tarriffs in the UK, this type of system has grown enormously in popularity in recent years. In these installations the home owner can sell the surplus energy back to the utility company. There are no batteries in the system, so this removes a lot of the system complication and maintenance; also the lack of batteries makes it cheaper to install.

If your aim is to become zero energy from the grid, then you need to ensure the electricity produced by your batteryless grid tied system is in excess of your total electricity usage for the year (calculated using one of the techniques above). However, this system should suit most budgets, because it will reduce reliance on the Energy Companies, by significantly reducing your bills. If you cannot produce all your electricity the shortfall is simply made up with electricity from the grid.

There is one major drawback with this set up, and that is that if there is a electrical power then you will have no power for your home, so you may require a generator (powered by Diesel or Oil) as a back-up policy.

GRID TIED SYSTEM WITH BATTERY BACKUP

This is essentially the same as the grid tied system above, but has a bank of batteries which means that if there is a grid power cut, the inverter can still get the electricity it requires to operate, so the installation will keep providing you with electricity. The constraints of this system are primarily associated with the batteries, which are expensive and also require regular maintenance. Finally add extra inefficiency into the system (ranging from 5 – 40%) and this is added to the constraint side.

OFF-GRID SYSTEMS

This system has no connection at all to the grid, relying instead on batteries to operate if no wind is blowing. However if the capacity of these batteries is too low, then you could be without any power for a prolonged period of time. Having a system off-grid presents an ideal situation as you become completely independent from the grid, and you produce all the electricity you need. However this type of system tends to be the most expensive and also is maintenance heavy. If you have a garden shed that needs lighting then this system can work out relatively cheaply, but as soon as you are looking to upscale then it becomes very expensive.

In the next section we look at the components that you need for a successful wind turbine installation.

Although all wind turbines operate on similar principles, several varieties are in use today. These include horizontal axis turbines and vertical axis turbines.

HORIZONTAL AXIS TURBINES

Horizontal axis turbines are the most common turbine configuration used today. They consist of a tall tower, atop which sits a fan-like rotor that faces into or away from the wind, a generator, a controller, and other components. Most horizontal axis turbines built today are two- or three-bladed.

Horizontal axis turbines sit high atop towers to take advantage of the stronger and less turbulent wind at 100 feet (30 meters) or more aboveground. Each blade acts like an airplane wing, so when wind blows, a pocket of low-pressure air forms on the downwind side of the blade. The low-pressure air pocket then pulls the blade toward it, which causes the rotor to turn. This is called lift. The force of the lift is actually much stronger than the wind's force against the front side of the blade, which is called drag. The combination of lift and drag causes the rotor to spin like a propeller, and the turning shaft spins a generator to make electricity.

VERTICAL AXIS TURBINES

Vertical axis turbines are of two types: Savonius and Darrieus. Neither type is in wide use.

The Darrieus turbine was invented in France in the 1920s. Often described as looking like an eggbeater, it has vertical blades that rotate into and out of the wind. Using aerodynamic lift, it can capture more energy than drag devices. The Giromill and cycloturbine are variants on the Darrieus turbine.

The Savonius turbine is S-shaped if viewed from above. This drag-type turbine turns relatively slowly but yields a high torque. It is useful for grinding grain, pumping water, and many other tasks, but its slow rotational speeds are not good for generating electricity.

In addition, wind turbines are still used for a variety of purposes. Windmills have been used by humans since at least 200 B.C. for grinding grain and pumping water. By the 1900s, windmills were used on farms and ranches in the United States to pump water and, later, to produce electricity. Windmills have more blades than modern wind turbines, and they rely on drag to rotate the blades.

Wind energy is becoming important source of energy in many countries of the world. Large wind farms with hundreds of turbines are becoming a rather common site in many places. In order for wind farm to generate maximum possible amount of power, wind energy developers need to ensure the optimum design for each wind farm.

In most cases there are complex computer models that do the work in terms of design. These programs need to find optimal solutions on spacing and orienting individual turbines to maximize their efficiency. The more power wind farm produces the bigger the revenue, so developers need to make sure every possible factor is included into program prior to construction.

There is no such thing as universal wind farm design because everything depends upon location and weather patterns on this location, meaning that developers need to come up with specific designs for each new location, in order to achieve maximum efficiency.

In some cases, the location that is chosen is even the result of political and social factors, so there are certainly plenty of factors which developers need to include in final equation prior to construction.

Wind farms design may vary from wind farms in which turbines are either installed in rows, which will be aligned against the prevailing winds, or in staggered, checkerboard-style blocks where each row of turbines is spaced to peek out between the gaps in the previous row. These staggered farms are in most cases the most efficient solution for large wind farms, though not always.

As the research continues to progress, there will of course be plenty of improvements in wind farm design in years to come. Wind energy developers are driven by the better power output in order to increase their revenues. The scientific work and the desire for better profits will no doubt lead to improvement in both design and efficiency of future wind farms.