Renewable energy is energy obtained from natural replenishment of energy sources, which are sustainable on a planetary timescale, such as carbon neutral renewable sources such as wind, sun, rain, tides, and geothermal heat; or non-renewable sources of energy, which include fossil fuels such as oil, gas, and coal. This energy can be obtained from the air, water, wind, or from radioactive decay of radioactive materials, among other potential sources. The most abundant naturally replenished energy source is the sun, which reaches its maximum potential in about 5 billion years, so theoretically one could live on the sun for billions and a half years. It is not however feasible to live on the sun for that long without depleting its supply of energy. Therefore humans have to use other methods for obtaining energy for the earth’s consumption.
One of the more prominent types of renewable energy used today is wind power. Wind turbines harness the inherent energy in wind, converting it into electricity that can be converted into electric current to run machines and appliances at home, businesses, and the infrastructure that supports them. A wind turbine spins, generating kinetic energy, which is converted to electrical energy when the rotor is moved by the force of wind. This energy can then be transmitted to the home using wind generators or batteries.
Another common way of harnessing renewable energy is through the use of water, either through collecting it from rivers and streams, or through evaporative cooling and heating systems. Some renewable energy sources emit pollutants in the atmosphere, such as carbon dioxide, whereas some use up less energy and make no contribution to global warming. It is important to reduce greenhouse gas emissions so that future generations can enjoy the benefits of a cleaner earth. It is also important to remember that all sources of renewable energy are potentially dangerous, potentially polluting the atmosphere, and therefore should only be used if safe alternatives are available.