Renewable Energy Sources

Renewable energy = any naturally occurring, theoretically inexhaustible source of energy, as biomass, solar, wind, tidal, wave, and hydroelectric power, that is not derived from fossil or nuclear fuel.

Renewable energy sources can be replenished in a short period of time. Many important events have occurred during the history of using renewable sources. The use of renewable energy is not new. 125 years ago, wood supplied up to 90 % of our energy needs. Now, some biomass that would normally be taken to the dump is converted into electricity, especially manufacturing wastes, rice hulls, and black liquor from paper production. Overall consumption from renewable sources in the United States totaled 6.8 quads (quadrillion Btu) in 2006, or about 7 % of all energy used nationally. Consumption from renewable sources was at its highest point in 1997, at about 7.2 quads.

The renewable sources used most often are:
· Hydropower
· Biomass
· Geothermal
· Wind

To begin, of the renewable energy sources that generate electricity, hydropower is the most often used. It is one of the oldest sources of energy. Because the source of hydropower is water, hydroelectric power plants must be located on a water source. Over one-half of the total U.S. hydroelectric capacity for electricity generation is concentrated in three States (Washington, California and Oregon). Irrigation, timber, mining and the building of homes are some examples of hydropower. Some problems with hydropower include fish passage and survival, water quality in reservoirs and downstream from dams, and altered flow organizations that may degrade physical habitat for fish below dams. Many economically feasible hydropower projects are financially challenged.

On the other hand, Biomass is organic material made from plants and animals. Biomass contains stored energy from the sun. Plants absorb the sun's energy in a process called photosynthesis. The chemical energy in plants gets passed on to animals and people that eat them. Biomass is a renewable energy source because we can always grow more trees and crops, and waste will always exist. Some examples of biomass fuels are wood, crops, manure, and some garbage. Biomass can pollute the air when it is burned, though not as much as fossil fuels. The feasibility of the utilization of woody biomass as energy resources in Japan is discussed based on its amount, availability, and energy-conversion technologies.

Next, the word geothermal comes from the Greek words geo (earth) and therme (heat). So, geothermal energy is heat from within the earth. We can use the steam and hot water produced inside the earth to heat buildings or generate electricity. Geothermal energy is a renewable energy source because the water is replenished by rainfall and the heat is continuously produced inside the earth. Geothermal energy is generated in the earth's core, about 4,000 miles below the surface. Scientists have been trying to recognize geothermal energy as the next leading source of energy. It is theorized that geothermal energy can be feasible and has the capability to become a prime energy source. Most geothermal reservoirs are deep underground with no visible clues showing above ground. Geothermal energy can sometimes find its way to the surface in the form of volcanoes, hot springs, and geysers.

Finally, wind is simple air in motion. It is caused by the uneven heating of the earth’s surface by the sun. Today, wind energy is mainly used to generate electricity. Wind is called a renewable energy source because the wind will blow as long as the sun shines. Over 5,000 years ago, the ancient Egyptians used wind to sail ships on the Nile River. Later, people built windmills to grind wheat and other grains. Some examples of this of renewable energy include wind farms, turbines, and windmills. Wind energy can be feasible where the average wind velocity is higher than 5–6 m/s.

I believe that recylcing is necessary. If the people of the world do not start recycling, our universe could become a dump in the future. Hydropower, wind, biomass, and geothermal energy are just a few examples of how things can be recycled and reused. Renewable energy sources can be replenished in a short period of time. Hopefully, with the practice of recycling, we can save our world from becoming disgusting!