As new technological innovations continue to offer new forms of clean and green power, the ability to live with less has become a reality. Solar, wind, geothermal, and hydro means of power make it possible to live “off the grid,” where dependence on natural kinds of power and energy replaces the dependence on more traditional power systems. Whether you’re living in a remote area or interested in energy savings, natural power source innovations are available in many different forms.
Off-grid power systems operate independently from power lines, whose generated energy can be used to power appliances. An off-grid solar system, for example, uses only the solar energy is gathers to power appliances in that system. An off-grid hybrid system, on the other hand, uses a combination of solar, hydro, and wind power as the main energy supply for a system.
When it comes to solar systems, many different configurations are available depending on the kind of power needed (AC or DC voltage). Most systems, regardless of their energy output, absorb solar energy in a similar fashion. Solar panels are one of the most commonly used methods for harnessing solar energy.
Solar panels are comprised of multiple solar cells, called photovoltaic cells, which absorb the sun’s energy and convert it into usable power. To do this, photovoltaic cells are comprised of semiconductor materials—such as silicon or cadmium telluride—which absorbs solar energy which in turn releases electrons. Metal contacts on various sides of the solar panel direct the free electrons in one direction, creating a current. The current, combined with voltage stored within the photovoltaic cells, is the end result and can be used to power devices.
A hydropower system uses the force of moving or falling water to generate energy. These systems range in size, depending on the amount of power desired: large hydropower system can produce enough energy to provide electricity for millions of homes, whereas smaller hydropower systems can be engineered to produce enough energy to provide power for one household.
Regardless of the size of the system, there are several elements that most hydropower systems share. First, a dam must be created, which is a barrier that essentially slows a moving body of water, thus raising the water level—the result is a small waterfall or controlled outpouring of water on the other side of the dam. As the water is released through the dam, it accumulates great force. A turbine, a device that operates in much the same way as a windmill, rotates as the water propels the turbine’s blades, and converts the energy of the water into mechanical energy. The turbine is connected to a generator which spins as a result of the spinning turbine, and converts the mechanical energy into electrical energy. Lastly, the electricity is fed into transmission lines, which carry the energy to homes or devices. The amount of energy created by a hydropower system is contingent upon the amount of water passing through the system and how far the water falls.
Wind energy systems harness kinetic energy from wind and turn it into mechanical or electrical energy, in much the same way hydropower systems gather energy from water. The primary device wind systems use is a wind turbine, which is available as a vertical axis and a horizontal axis turbine.
The most commonly used type of wind turbine is a horizontal axis turbine, which is typically used in large scale wind systems that harness 100 kilowatts and higher. Most turbines include the following elements: a rotor, a nacelle, a tower, and some electronic equipment.
In the same way that a hydro turbine depends on rotors to rotate, the rotors of a wind turbine propel the turbine when they encounter wind. The nacelle houses the generator, which spin as the rotors spin. The tower supports the rotor, narcelle, and electronic equipment, which helps feed the electricity generated by the wind turbine into utility power lines. Depending on the size of the turbine, capacities as large as 5,000 kilowatts can be reached.
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