ALTERNATIVE ENERGY SOURCES
The world has changed a great deal since the Industrial Revolution. In just the past 50 years, humans have made unparalleled strides in the theory and practical application of science and technology. This becomes self evident as we look around and see how science has changed our lives. We live in climate-controlled houses, drive cars and fly in airplanes to reach far away destinations, communicate by computer, enjoy refrigerated beverages and foods, and have the ability to light up the night with electricity. At no point in human history has humankind enjoyed so many fruits of technology. It is often tempting to believe that this modern world we have created is a better place in which to live simply because it is a more convenient place in which to live.
However, the more we expand our horizons with modern technology the more we become trapped by it. We are now dependent upon our lights, cars, air conditioning and computers – and almost all of them are powered by resources which are rapidly running out. The electricity that runs almost everything we use is generated mainly by coal, oil, natural gas or nuclear energy. Coal, oil, and natural gas are all fossil fuels. Once burned, they can never be used again – and their byproducts, such as carbon dioxide, carbon monoxide, oxides of nitrogen and sulfur dioxide all contribute to degradation of the atmosphere and environment. Nuclear energy presents its own set of problems, not the least of which is the containment of its toxic waste byproducts and the extremely long half-life of uranium.We are burning fossil fuels at an unprecedented rate, despite our realization the production of these fuels cannot continue indefinitely.
Fortunately, there is. Scientists are working hard to develop large scale applications for renewable energy sources, which is also be used to make electricity, power cars and heat and cool our homes. Renewable energy comes from resources which will never run out, such as sunlight, water, wind, biomass and waste products. These forms of energy are our best hope for a life and world which will be cleaner and more efficient, and many are being used today.
Solar energy is one the most resourceful sources of energy . One of the reasons for this is that the total energy we recieve each year from the sun is around 35,000 times the total energy used by man. However, about 1/3 of this energy is either absorbed by the outer atmosphere or reflected back into space (a proccess called albedo).Solar energy is presently being used on a smaller scale in furnaces for homes and to heat up swimming pools. On a larger scale use, solar energy could be used to run cars, power plants …
Wind power is another alternative energy source that could be used without producing by-products that are harmful to nature. Like solar power, harnessing the wind is highly dependent upon weather and location. The average wind velocity of Earth is around 9 m/sec. And the power that could be produced when a wind mill is facing the wind of 10 mi/hr. is around 50 watts.
Hydroelectricity comes from the damming of rivers and utilizing the potential energy stored in the water. As the water stored behind a dam is released at high pressure, its kinetic energy is transferred onto turbine blades and used to generate electricity. This system has enormous costs up front, but has relatively low maintenance costs and provides power quite cheaply. Even the power of the tides can be harnessed to produce electricity. Similar to the more conventional hydroelectric dams, the tidal process utilizes the natural motion of the tides to fill reservoirs, which are then slowly discharged through electricity-producing turbines.
Geothermal energy is the heat from the center of the Earth and it is a clean and sustainable energy. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth’s surface, and down even deeper to the extremely high temperatures of molten rock called magma.Almost everywhere, the shallow ground or upper 10 feet of the Earth’s surface maintains a nearly constant temperature between 50° and 60°F (10° and 16°C).Geothermal heat pumps (GHP) can tap into this resource to heat and cool buildings. A GHP system consists of a heat pump, an air delivery system (ductwork), and a heat exchanger&mdasha system of pipes buried in the shallow ground near the building.In the winter, the heat pump removes heat from the heat exchanger and pumps it into the indoor air delivery system. In the summer, the process is reversed, and the heat pump moves heat from the indoor air into the heat exchanger. The heat removed from the indoor air during the summer can also be used to heat water, providing a free source of hot water.