Andrea T. Bailey
The practical sources of energy include fossil fuels: natural gas, oil, and coal. Fossil fuels are referred to as nonrenewable energy sources because once they are used they are gone. Many people are exploring other sources of energy called renewable energy sources. These energy sources include sun, wind, geothermal, hydropower, and biomass. The renewable energy resources are very important in our future energy planning because they will never be exhausted.
Solar Energy
The sun is 93 million miles away and still, this hot gas ball is the primary source of all energy on earth. This energy comes from the thermonuclear reaction of fusing hydrogen atoms to form helium, a reaction responsible for the sun to exist. Without the sun, fossil fuels could have never existed. The sun is the energy supplier that also runs the water cycle. The heating of the earth, which is uneven, produces wind energy. Solar energy may also be used to cook food, heat water and generate electricity. It is still the cleanest energy source and it is renewable. The potential for solar energy is vast and should represent a major part of our energy for the future throughout the United States. It is an unlimited supply of energy and causes no pollution to the air or water. However, geographic location, time of day and seasonal change affects the amount of energy received by a solar collector. This causes some reliability issues and a need for storage or a backup source because of the availability of the sunlight.
Wind Energy
Wind is created when the earth is heated unequally creating a difference of temperature, density and pressure within the earth's atmosphere. This wind energy can be converted into mechanical and electrical energy. For thousands of years, wind turbines have been used to convert kinetic energy to mechanical energy that allows simple machines to grind grain and pump water. Today we use wind turbines to produce electricity. Large wind farms produce most of electricity generated by wind turbines. The wind farms sell the electricity generated to utility companies for distribution. The Public Utility Regulatory Act (PURPA) states that the producers of the wind energy sell the electricity at a reasonable rate. Electricity-generating wind turbines are not harmful to the water and do not produce air pollution. These wind farms are inexpensive to build and other crops can be planted on the unused land. Wind patterns can cause a fluctuation in a constant significant amount of wind needed. A common concern is the visual impact the wind turbines have on the cities and homes around them (3).
Geothermal Energy
Geothermal energy is energy found deep within the earth. Geothermal energy is the only renewable energy that does not come from the sun. Decay of radioactive elements (thorium and uranium) in the earth's core releases heat, which gets trapped below the surface of the earth. In deep fault areas, water is heated by the deep rocks below. The contact causes the water to heat up and come back to the earth's surface where it can be captured for use. This energy is not popular in the United States. Native Americans used hot springs for cooking and the Greeks and Romans built public baths over hot springs. Some even heat their homes with it when it is captured. Since 1960, large reservoirs of geothermal steam and other hot water reservoirs in the western United States have been tapped to generate 3,000 megawatts of electricity (4). There are four types of geothermal resources: Hot dry rocks, magma, geopressured brines and hydrothermal reservoirs (water and steam). Hydrothermal reservoirs are more commonly used. Geothermal energy supply is unlimited and very clean. It provides no water or air pollution. Any waste emitted (salt or minerals) can be pumped deep into the ground where no harm is found. Start up costs may be expensive as well as maintaining the area due to corrosion. Heat transfer through rocks is also a slow process. As a result, geothermal plants will use up the available geothermal heat and become inefficient over time unless new geothermal wells are drilled.
Hydropower Energy
Hydropower is water that is trapped behind dams; the trapped energy is a source of electricity. The monstrous amount of falling water has the ability to turn giant turbines. The turbines enable the generators to work, which produce electricity. The amount of power is determined by the amount of water and the distance the water falls. As water moves through the turbine, the kinetic energy of the flowing water is turned into mechanical energy. This energy can be used to grind grain, move a sawmill, pump water and provide electricity. There are many types of turbines that capture kinetic energy. Run-of-the-river turbines and the spinning turbine do not need a dam and have a very low environmental impact. The most commonly used hydropower system uses energy from falling water. A dam is used to capture the water. The larger the drop, the more energy is captured. A turbine is used to collect the kinetic energy. Some rivers have more than one dam and hydropower station. Water power is a clean source of electricity. The cost is low once the entire station has been constructed. The energy produced is free once the equipment costs needed to capture the energy have been paid back. Water reservoirs offer recreational benefits as well (boating and fishing) and can be used with solar and wind power. Hydropower does have its environmental impacts although. Dams cause flooding and cover a larger area than solar plants that produce the same amount of energy. Ecosystems will also be disrupted as running water will now be moving in a calm stream and ponds.
Biomass Energy
Biomass is a term used to describe energy that is derived from garbage and wood. Garbage sites are feeding grounds for bacteria growth. As bacteria decompose the garbage, methane is produced. This methane is the same as natural gas found in the ground. There are a number of power plants in the United States, which are run by methane from these organic wastes, mostly manure. Biomass in the form of wood is the oldest form of renewable energy. Wood has been used to produce heat and for cooking. Some cities even produce electricity by burning the garbage in designed power plants. Biomass is a local energy source especially to those that live in wooded areas and high urban areas have a constant production of waste. Burning wood or dried sewage pollutes the air at the same rate as fossil fuels. Cutting down wood to fuel these plants also disrupts the habitats of other species.
Conservation of Energy
The conversion of energy from one form to another is governed by a natural law: The Law of Conservation. This law states that energy can be neither created nor destroyed; it can only be changed from one form to another. As energy performs work it changes from a more concentrated form of energy to a less concentrated form. Energy that goes into a typical light bulb becomes light and heat. When you touch a light bulb it feels very hot. The chemical energy of gasoline is converted into mechanical energy that moves a car and some of that energy is lost into the environment. You can see this when you stand near a car that is not moving and feel the heat. This is a very important reason why we should conserve or save energy.
Saving energy will allow us more for another day. It will also cut down on the pollution and help energy last longer until our renewable energy sources are more available. This is why it is so important that we educate the students. These students are our future consumers. We need to teach them to make better choices on the types and how much energy they do use. In doing so, we will allow the energy we have to last longer and continue to change the availability of renewable energy sources.