Tag Archives: Wind Turbines

Energy Harvesting – How & Why

What Is Energy Harvesting – Why Is It Needed?

The process of extracting small quantities of energy from one or more natural, inexhaustible sources, accumulation and storage for subsequent use at an affordable cost is called Energy Harvesting. Specially developed electronic devices that enable this task are termed Energy Harvesting Devices.

The world is facing acute energy crisis and global warming, stemming from rapid depletion of the traditional sources of energy such as oil, coal, fossil fuels, etc., which are on the verge of exhaustion. Not only is the global economy nose-diving, but the damage to the environment is also threatening our very existence. Natural calamities like earthquakes, tsunamis, droughts, floods, storms, etc., have become the order of the day. Economic growth is generating a spiraling demand for energy, goading us to tap alternative sources of energy on a war footing. Our very existence on the planet Earth is at stake, and we must find immediate solutions to meet the energy needs for survival.

Alternative Energy Sources Available

There are many, almost inexhaustible, sources of energy in nature. In addition, these energy forms are available almost free, if available close to the place where required. Sources include: Solar Energy, Wind Energy, Tidal Energy, Energy from the waves of the ocean, Bio Energy, Electromagnetic Energy, Chemical Energy, and so on.

Recent Advances in Technology

The sources listed above provide miniscule quantities of energy. The challenge before us is to gather the miniscule amounts and generate meaningful quantities of energy at affordable cost. Until very recently, this has remained an unfulfilled challenge.

Today, research and innovation has resulted in creation of more efficient devices to capture minute amounts of energy from these sources and convert them into electrical energy. Besides, better technology has led to lower power consumption, and hence higher power efficiency. These have been the major propelling factors for better, more efficient energy harvesting techniques, making it a viable solution. These solutions are considered to be more reliable and relatively maintenance free compared to traditional wall sockets, expensive batteries, etc.

Basic Building Blocks of an Energy Harvesting System

An Energy Harvesting System essentially consists of:

a) One or more sources of renewable energy (solar, wind, ocean or other type of energy)
b) An appropriate transducer to capture the energy and to convert it into electrical energy (such as solar cells for use in conjunction with solar power, a windmill for wind power, a turbine for hydro power, etc.)
c) An energy harvesting module to accumulate, store and control electrical power
d) A means of conveying the power to the user application (such as a transmission line)
e) The user application that consumes the power

With advancement in technology, various interface modules are commercially available at affordable prices. Combined with the enhanced awareness of the efficacy of Energy Harvesting, more and more applications and utilities are progressively using alternative sources of energy, which is a definite sign of progress to effectively deal with the global energy crisis.

Optional addition of power conditioning systems like voltage boosters, etc., can enhance the applications, but one must remember that such devices also consume power, which again brings down the efficiency and adds to cost.

What is a wind turbine?

A wind turbine is a rotary device that draws energy from the wind. This is different from a windmill, which draws energy from the wind but that energy is directly converted into mechanical energy used by some sort of machinery. Wind turbines are converted into raw electricity.

There are two main types, horizontal and vertical axis, of which the horizontal axis is more common. What are the differences between these two? Horizontal-axis turbines have the main rotor shaft and generator at the top of the tower. Horizontal axes must be pointed into the wind in order for them to work properly. However, the structure of the blades facing the wind also gives them a great angle of attack, which is the angle at which they have contact with the wind. This insures that the blades will be very efficient when converting wind to energy. Vertical-axis turbines are basically the same, except the axis is vertical, and they have the advantage of not having to face the wind.

Wind turbines are made up of three main components, the rotor component, generator component, and structural support component. The rotor component makes up about 20% of the cost, and consists of the blades. The generator component makes up 34% of the cost, and consists of the electrical generator, the control electronics, and usually a gearbox component for converting the low speed incoming rotation to high speed rotation which is better for generating electricity. Finally the structural support component makes up about 15% of the cost and consists of tower and rotor yaw mechanism.

Installing wind turbines can be a great way to save money on your electrical bills and create your own energy. They can be bought pretty inexpensively or you can even build your own and get the supplies to do it for even cheaper. If you are interested in building a basic wind turbine to see how it works, you should buy an educational wind turbine kit to get you started.