Man's Use of Energy - Essay Example

Man’s use of energy Introduction Energy is defined as the ability or the capa to do work. The most common definition of energy is the work that acertain force (gravitational, electromagnetic, etc) can do. The SI unit of energy, the joule, equals one newton applied through one meter. Energy is a conserved quantity, in other words it cannot be created or destroyed, but only converted from one form into another. Thus, the total energy of the universe always remains constant (Wikipedia, 2006). There are two types of energy, renewable and non-renewable sources of energy. The non-renewable sources of energy such as coal, natural gas, and mineral oil are gradually becoming exhausted as we are over-tapping these resources (TERI, 2006). They are also called fossil fuels because they were formed over millions and millions of years by the action of heat from the Earths core and pressure from rock and soil on the remains (or "fossils") of dead plants and animals.  Another non-renewable energy source is the element uranium, whose atoms is split to create heat and ultimately electricity (EIA, 2006). Due to the problems associated with the use of fossil fuels, alternative sources of energy have become important and relevant in today’s world. Energy generated from the sun is known as solar energy. Hydel is the energy derived from water. Biomass – firewood, animal dung, and biodegradable waste from cities and crop residues – is a source of energy when it is burnt. Geothermal energy is derived from hot dry rocks, magma, hot water springs, natural geysers, etc. Ocean thermal is energy derived from waves and also from tidal waves. Today the society is looking towards these alternative sources of energy for taping energy. These are the renewable sources of energy and will not exhaust. Also known as non-conventional sources of energy, they cause less emission and are environment friendly. Their use can significantly reduce chemical, radioactive, and thermal pollution. They are feasible sources of clean and limitless energy. Most of the renewable sources of energy are fairly non-polluting and considered clean. However, biomass is a major polluter indoors (TERI, 2006). Renewable energy is for several reasons an attractive option for adding safe and clean energy capacity. Despite these attributes, renewable energy currently contributes only a small share to overall energy capacity— about 2% of global primary energy use and 4.4% of global installed electricity generation capacity. These numbers notwithstanding, renewable energy use is growing. In fact, it is the largest growing energy supply sector overall. Between 2000 and 2004, wind capacity grew 29%, grid-connected solar photovoltaics grew 61%, and off-grid solar photovoltaics grew 17%. And although renewable energy was initially driven by Northern countries, developing countries now account for 44% of the globally installed renewable power capacity (Good, 2006). History of energy use by man Sun was the first energy source which provided light and heat to early humans. The discovery of fire by man led to the possibility of burning wood for cooking and heating thereby using energy. For several thousand years human energy demands were met only by renewable energy sources—sun, biomass (wood, leaves, twigs), hydel (water) and wind power. As early as 4000–3500 BC, the first sailing ships and windmills were developed harnessing wind energy. With the use of hydropower through water mills or irrigation systems, things began to move faster. Fuel wood and dung cakes are even today a major source of energy in different parts of the world. Solar energy is used for drying and heating (TERI, 2006). Early Egyptians collected oil that floated to the top of ponds and used it to burn for light. American Indians burned coal to bake clay pots. Ancient Chinese people used natural gas to heat sea water for salt. They also piped the gas from shallow wells. During this time people started using the geothermal energy (Elementary Energy Infobook, 6-7). Energy use by modern man Modern man is known for his use of energy. In fact, no other century — no millennium — in human history can compare with the 20th for its growth in energy use. Man has probably deployed more energy since 1900 than in all of human history before 1900. Calculations suggest that the world in the 20th century used 10 times as much energy as in the thousand years before 1900 A.D. In the 100 centuries between the dawn of agriculture and 1900, people used only about two-thirds as much energy as in the 20th century (McNeill, 2001). With the beginning of Industrial Revolution, the use of energy in the form of fossil fuels began growing as more and more industries were set up. This occurred in stages, from the exploitation of coal deposits to the exploitation of oil and natural gas fields. It has been only half a century since nuclear power began being used as an energy source. In the past century, it became evident that the consumption of non-renewable sources of energy had caused more environmental damage than any other human activity. Electricity generated from fossil fuels such as coal and crude oil has led to high concentrations of dangerous gases in the atmosphere. This has in turn led to problems such as ozone depletion and global warming. Vehicular pollution is also a serious problem (TERI, 2006). Energy in Biology Food is the source of energy used by people. Food that we eat is digested, and the stored energy is used by the body for maintenance, growth and development. Growth, development and metabolism are some of the central phenomena in the study of biology and all of them cannot be explained without invoking the energy concept. Indeed sustenance of life itself is critically dependent on energy transformations. In a living organism chemical bonds are constantly broken and made to make the exchange and transformation of energy possible. These chemical bonds are most often bonds in carbohydrates, including sugars. Other chemical bonds include bonds in ATP and acetate, which in turn is derived from fats and oils1. These molecules, along with oxygen, are common stores of concentrated energy for the biological processes (Wikipedia, 2006). Energy and the environment Consumption of energy resources is apparently harmless. However, producing that energy requires resources and contributes to air and water pollution. Many electric power plants burn coal oil or natural gas in order to generate electricity for energy needs. While burning these fossil fuels produces a readily available and instantaneous supply of electricity, it also generates air pollutants including carbon dioxide (CO2), sulphur dioxide and trioxide (SOx) and nitrogen oxides (NOx). Carbon dioxide is an important greenhouse gas which is thought to be responsible for some fraction of the rapid increase in global warming seen especially temperature records in the 19th century, as compared with tens of thousands of years worth of temperature records which can be read from ice cores taken in artic regions. Burning fossil fuels for electricity generation also releases trace metals such as beryllium, cadmium, chromium, copper, manganese, mercury, nickel, and silver into the environment, which also act as pollutants. On the other hand certain renewable energy technologies do not pollute the environment in the same ways, and therefore can help contribute to a cleaner energy future for the world (UNDP, 2006). Renewable energy technologies available for electricity production include biofuels, solar power, tidal power, wind turbines, hydroelectric power etc (Wikipedia, 2006). Economics of energy Production and consumption of energy resources is very significant to the global economy. All economic activity requires energy resources, starting from the manufacturing of goods, providing transportation, running computers and other machines, or to grow food to feed workers, or even to harvest new fuels. Thus the way in which a human society uses its existing energy resources, develops means of their production or acquisition is a defining characteristic of its economy. The progression from animal power to steam power, then the internal combustion engine and electricity, are key elements in the development of modern civilization. The cost of energy resources depends on its demand and production at any particular time. Scarcity of cheap fuels is a key concern in future energy development (Wikipedia, 2006). Conclusion Concerns over the negative environmental impacts of inefficient uses of energy are growing, both globally and regionally. Today there is awareness among people to conserve energy and are making a conscious effort to conserve it and thereby put less pressure on the earth. By conserving energy the environment is also protected from harmful pollutants. Such concerns involve national and international cooperation to promote energy efficiency and energy conservation. More efficient energy use can increase productivity and economic competitiveness as well as lower greenhouse gas emissions per unit of output. Work Cited Elementary Energy Infobook, History of Energy. The Need Project, Manassas, pp 6-7. 28 Nov. 2006 Energy Information Administration (EIA), Energy Kids Page Official energy statistics from U.S. Government 2006. 28 Nov. 2006 Good, L. The Importance of Policies for Grid-Connected Renewables Global Environment Facility, February 1, 2006. International Grid-Connected Renewable Energy Policy Forum, Mexico. 28 Nov. 2006 McNeill, J.R. The History of Energy Since 10,000 B.C. In: Something New Under the Sun (2001). The Globalist. TERI, Energy 2006. EduGreen. 28 Nov. 2006. UNDP, Energy and Environment for Sustainable Development (2006) United Nations Development Programme 28 Nov. 2006 Wikipedia, Energy 27 November 2006 Wikimedia Foundation, Inc. 28 Nov. 2006. Read More