A Brief Overview of Renewable Energy Sources

Five Main Types of Green Power Defined

Jan 26, 2010 Minka Gantenbein

What are renewable energy sources?
They are infinite energy sources that can never be used up.
Here's an overview of five of these naturally generated energy sources.

Renewable energy sources are types of energy which can be naturally replenished. According to the U.S. Energy Information Administration's Annual Energy Review published in June 2009, the five main types of renewable energy are solar power, wind power, hydropower, biofuels and geothermal energy. Fossil fuels such as coal, oil and natural gas are not renewable energy sources because there is a finite amount of them which will eventually run out.

Renewable energy can come from the sun either directly or indirectly, from wind, from moving water or other natural movements of the environment. These green energy sources are non-polluting and environmentally friendly.

What is Solar Power?

Solar power converts sunlight into electricity by using solar panels. These solar panels collect sunlight through solar cells which is known as the photovoltaic effect. The silicon in photovoltaic cells converts the sunlight into electricity instead of heat.

There is very little maintenance required for this type of energy. An average photovoltaic cell can last up to 40 years. Solar power is free, needs no fuel and produces no pollution or waste.

What is Wind Power?

Wind power is made by wind turbines capturing wind. The blades from the turbines catch the wind's motion, which rotates the shaft and transfers energy into the turbine's generator. That generator then turns the energy into electricity.

Building several turbines close together generates more electricity, and is known as a wind farm. Wind power is a good way to supply energy to remote areas, but must be built in areas that maintain strong, steady winds in order to be effective.

What is Hydropower?

Hydropower, also known as water power, harnesses the energy of moving water and uses it for electricity production. Hydropower can be generated by hydroelectric power, wave power and tidal power, all which use the natural force of water.

Hydroelectric power is the most common form of hydropower. It works by capturing falling water into a waterwheel or turbine that then powers a generator to produce electricity.

What are Biofuels?

Biofuels are any fuel obtained from biological materials that can be regenerated. Methanol, ethanol and biodiesel are some of the fuels that fall into this category. Biofuels like biodiesel can be made from vegetable oil or animal fat. Other biofuels are derived from various plant materials.

Biofuels can be used to supplement or replace fossil fuels like petroleum and diesel. They can reduce global warming due to the fact that biofuels are carbon neutral.

What is Geothermal Energy?

Geothermal energy is power that comes from heat stored inside the interior of the earth. Molten rock heats the water underground, which turns generator turbines that produce electricity. It is energy derived from the natural heat of the earth.

Geothermal energy can be used directly for heating purposes. For example, according to the February 2004 study, Energy In Iceland: Historical Perspective, Present Status, Future Outlook, published by the National Energy Authority and Ministries of Industry and Commerce, the country of Iceland gets more than 50 percent of its energy from geothermal resources.

The more we utilize renewable energy sources, and the less we use fossil fuel, the more we benefit the environment. Renewable energy sources are clean, green ways of creating power by using the natural elements provided by our planet.