Different Types of Alternative Energy Sources

 

There are many reasons the world is looking for alternative energy sources in an effort to reduce pollutants and greenhouse gases. Alternative energy sources show significant promise in helping to reduce the amount of toxins that are by-products of energy use and help preserve many of the natural resources that we currently use as sources of energy. To understand how alternative energy use can help preserve the delicate ecological balance of the planet, and help us conserve the non-renewable energy sources like fossil fuels, it is important to know what types of alternative energy can be found at present. Let us take a look at some of the most common sources available.

a) Hydroelectric Power

By taking advantage of gravity and the water cycle, we have tapped into one of nature's engines to create a useful form of energy. In fact, humans have been capturing the energy of moving water for thousands of years. Today, harnessing the power of moving water to generate electricity, known as hydroelectric power, is the largest source of emissions-free, inexhaustible electricity worldwide.

Although the generation of hydropower does not emit air pollution or greenhouse gas emissions, it can have negative environmental and social consequences. Blocking rivers with dams can degrade water quality, damage aquatic habitat, block migratory fish passage, and displace local communities. The benefits and drawbacks of any proposed hydropower development must be weighed before moving forward with any project.

In order to generate electricity from the kinetic energy in moving water, the water has to move with sufficient speed and volume to spin a propeller-like device called a turbine, which in turn rotates a generator to generate electricity. Roughly speaking, one gallon of water per second falling one hundred feet can generate one kilowatt of electricity.

b) Wind Power  

Wind energy harnesses the power of the wind to propel the blades of wind turbines. The rotation of turbine blades is converted into electrical current by means of an electrical generator. In the older windmills, wind energy was used to turn mechanical machinery to do physical work like crushing grain or pumping water. Wind towers are usually built together on wind farms. Now, electrical currents are harnessed by large-scale wind farms that are used by national electrical grids as well as small individual turbines used for providing electricity to isolated locations or individual homes. In 2005, worldwide capacity of wind-powered generators was 58,982 megawatts, their production making up less than 1 percent of worldwide electricity use.

Wind power produces no pollution that can contaminate the environment since no chemical processes take place and no harmful by-products left over as in the burning of fossil fuel; since wind generation is an inexhaustible source of energy, we will never run out of it; farming and grazing can still take place on land occupied by wind turbines which can help in the production of biofuels.

However, consistent wind is needed for continuous power generation. If wind speed decreases, the turbine will stop.

c) Solar Power

 Solar energy is used commonly for heating, cooking, the production of electricity, and even in the desalination of seawater. Solar power works by trapping the sun's rays into solar cells where this sunlight is then converted into electricity. Additionally, solar power uses sunlight that hits solar thermal panels to convert sunlight to heat water or air. Other methods include using sunlight that hits parabolic mirrors to heat water (producing steam), or simply opening room blinds or window shades to allow entering sunlight to passively heat a room.

Solar power generation releases no water or air pollutants because there is no chemical reaction from the combustion of fuels; solar energy can be applied very efficiently for practical uses such as heating and lighting; the benefits of solar power are seen frequently to heat pools, spas, and water tanks all over.

But solar power does not produce energy if the sun is not shining; nighttime and cloudy days seriously limit the amount of energy produced; moreover, solar power stations can be very expensive to build.

d) Geothermal Energy

Geothermal literally means "earth heat." Geothermal energy harnesses the heat energy which is present underneath the Earth. Hot rocks under the ground heat water to produce steam. When holes are drilled in the region, the steam that shoots up is purified and is used to drive turbines, which power electric generators.

If done correctly, geothermal energy produces no harmful by-products; geothermal power plants are usually small and have little effect on the natural landscape. If done incorrectly, geothermal energy can produce pollutants, improper drilling into the earth can release hazardous minerals and gases; geothermal sites are prone to running out of steam.

E) Tidal Energy

Another variation is to make use of water's kinetic energy such as wave and tidal power. Although still in its development stage, there are two ocean-based technologies with high potential for providing a clean, free alternative energy source in the future. Wave power uses the kinetic energy of the ebbing, flowing of the oceans waves and tides by trapping water in tidal barrages or through underwater tunnels, which is then used to rotate tidal turbines. Tidal power also uses large turbines fixed to the sea bed or just below the surface of the waves to capture the energy from strong tidal currents.

The rise and fall of ocean tides contain enormous amounts of energy that can be captured to produce electricity. In order for tidal power to be effective, however, the difference in height between low and high tides needs to be at least 20 feet (6 meters), and there are only a few places in the world where this occurs. A tidal station works like a hydropower dam, with its turbines spinning as the tide flows through them in the mouths of bays or estuaries (an arm of the sea at the lower end of a river), generating electricity. By the end of the twentieth century, tidal power plants were in operation in France, Russia, Canada, and China.     Ocean thermal energy uses the temperature change between the warmer surface waters and the colder depths to produce electrical power.

F) Biomass Energy

Certain biomass (the sum of living and dead plants, animals, and microorganisms in an area) can be used as fuel to produce heat energy. Wood, crops and crop waste, and wastes of plant, mineral, and animal matter are part of the biomass. The biomass contained in garbage can be burned to produce heat energy or can be allowed to decay and produce methane (natural gas). In Western Europe, over 200 power plants burn rubbish to produce electricity. Methane can be converted to the liquid fuel methanol, and ethanol can be produced from fermentable crops such as sugar cane and sorghum. Adequate air pollution control is necessary when biomass is burned to limit the release of carbon dioxide into the atmosphere.