Energy is the ability to do work
Over the centuries we've used all kinds of different things as sources of energy; wood, whale oil, coal and most recently fossil fuels (oil, natural gas, etc...)
Fossil Fuel had its origin millions and millions of years ago from the remains of plants and animals. Its massive use as the main energy source has contributed to a huge increase of air pollution, especially noticed in big cities. It is also unsustainable, in other words, it is being used more rapidly than the time it takes for it to replenish itself. To avoid an energy crises and in order to guarantee a healthier future, we have to start using sustainable and clean forms of energy.
Sustainable energy comes from sources that can be used forever (e.g. the sun) or from sources that naturally replenish themselves quickly enough to make the source effectively everlasting
The solution to our energy needs is as complex as the problem itself. The best way to achieve a balance between supply and demand is to take advantage of the natural resources available in our area.
If you live in a windy area, the wind may be the best alternative to use as an energy source. If your area has plenty of sunlight, solar energy may be a better choice. However, a combination of these energy types and others can provide enough energy to sustain our demand.
Here are some examples of renewable energy:
Quick growing plant crops and plant residues can be converted into fuels or burned to produce electricity.
Is a fuel made from plants. Biofuel can be used alone or with a combination of other fuels. Since it contains oxygen, biofuel can be added to gasoline or diesel for a cleaner burn.
Ethanol (a type of alcohol)
Is one of the most common biofuels. Brazil, the world’s largest producer of ethanol, makes its ethanol using sugar cane. The United States, the second largest producer of ethanol uses corn.
Has its origin deep within the earth's core. Water is pumped into the ground, heated and transformed into steam that is used to generate power.
Water from rivers (moving water) is used to generate electricity.
When the atomic nuclei of certain elements (e.g. uranium) is split it releases great amounts of heat. The heat transforms water into steam that powers giant electric generators.
Passive - Specially designed pipes heat water as it flows through them. The heated water is then stored in a tank. This application is mainly used in residences.
Active - Solar cells (photovoltaic or PV cells) like those on our solar car, transform sunlight into electricity.
Tides originate from the attractive force (gravity) that exists between the earth, moon and sun. The movement of rising and falling water is used to generate energy.
Is produced by burning garbage (waste) to generate electricity. Some industries like paper mills use waste to fuel boilers which in turn generate steam for running machinery in their plants.
As air moves and creates wind, the energy can be harvested by wind turbines that transform it into electricity.