RENEWABLE ENERGY SOURCES

What is renewable energy?

Energy exists freely in nature. Some of them exist infinitely (never run out, called RENEWABLE), the rest have finite amounts (they took millions of years to form, and will run out one day, called NON-RENEWABLE)

Let's look at these types of energy in the diagram above.You will notice that water, wind, sun and biomass (vegetation) are all available naturally and were not formed. The others do not exist by themselves, they were formed. Renewable energy resources are always available to be tapped, and will not run out. This is why some people call it Green Energy.

What is Biomass?

Biomass fuels come from things that once lived: wood products, dried vegetation, crop residues, aquatic plants and even garbage. It is known as 'Natural Material'. Plants used up a lot of the sun's energy to make their own food (photosysnthesis). They stored the foods in the plants in the form of chemical energy. As the plants died, the energy is trapped in the residue. This trapped energy is usually released by burning and can be converted into biomass energy.

How is biomass converted into energy?

BurningThis is a very common way of converting organic matter into energy.

DecompositionThings that can rot, like garbage, human and animal waste, dead animals and the like can be left to rot, releasing a gas called biogas (also known as methane gas or landfill gas).

FermentationEthanol can be produced from crops with lots if sugars, like corn and sugarcane. The process used to produce ethanol is called gasification.

What is Wind Power?

The earth's surface has both land and water. When the sun comes up, the air over the land heats up quicker than that over water. The heated air is lighter and it rises. The cooler air is denser and it falls and replaced the air over the land. In the night the reverse happens. Air over the water is warmer and rises, and is replaced by cooler air from land.

The moving air (wind) has huge amounts of kinetic energy, and this can be transferred into electrical energy using wind turbines. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity. The electricity is sent through transmission and distribution lines to a substation, then on to homes, business and schools.

Water power

Water power schemeMoving water has kinetic energy. This can be transferred into useful energy in different ways. Hydroelectric power (HEP) schemes store water high up in dams. The water has gravitational potential energy which is released when it falls.

Sluice Gates: These can open and close to regulate the amount of water that is released into the pipes.

Geothermal

In some places the rocks underground are hot. Deep wells can be drilled and cold water pumped down. The water runs through fractures in the rocks and is heated up. It returns to the surface as hot water and steam, where its' energy can be used to drive turbines and electricity generators.Geothermal energy is called a renewable energy source because the water is replenished by rainfall, and the heat is continuously produced by the earth.

Geothermal energy scheme

Solar power

"Solar" is the Latin word for "sun" and it's a powerful source of energy. Without it, there will be no life. Solar energy is considered as a serious source of energy for many years because of the vast amounts of energy that is made freely available, if harnessed by modern technology.It is renewable!solar energy kidsThe technology used to convert the sun's power into electricity does not produce smoke (carbon dioxide and other air pollutants).

Tapping the sun's energy does not usually destroy the environment.

Unfortunately, the sun does not available in the night, and in some days, clouds and rains and other natural conditions prevent the sun's powerful rays to reach us. This means that it is not always available. This a why we cannot rely on solar energy alone.

Solar

Solar Panels

Solar panels do not generate electricity directly. Instead they heat up water directly. A pump pushes cold water from a storage tank through pipes in the solar panel. The water is heated by heat energy from the Sun and returns to the tank. They are often located on the roofs of buildings where they can receive the most sunlight.