INTRODUCTION A fossil fuel is a natural substance substance formed from the buried remains of ancient organisms that can be used as a source of energy Fossil fuels formed over millions of years as heat and pressure from layers of sediment changed the decayed organic remains into materials such as coal and petroleum The energy in fossil fuels is the energy from sunlight stored in the tissues tissues of the buried organisms as a result of photosynthesis Fossil fuels may be solids liquids or gases All fossil fuels are hydrocarbons a class of chemicals composed only of carbon carbon and hydrogen atoms Coal petroleum and natural gas are the most commonly commonly known fossil fuels All fossil fuels can be burned in air or with oxygen derived from air to provide heat This 4
This power plant is burning coal to generate electricity Like natural gas and oil coal is a fossil fuel heat may be employed directly as in the case of home furnaces or used to produce steam to drive generators that can supply electricity In still other cases for example gas turbines used 5
FOSSIL FUELS in jet aircraft the heat yielded by burning a fossil fuel serves to increase both the pressure and the temperature of the combustion products to furnish motive power Fossil fuels are not distributed evenly across the Earth The United States Russia and China have the largest coal deposits in the world Sizable deposits also are located in Australia India and South Africa More than half of the world’s known oil and natural gas reserves are located in the Middle East This means that the Middle East contains more oil than the rest of the world combined Major reserves are also found in Canada and the United States Latin America Africa and parts of Russia Transcaucasia and Central Asia Each of these regions contains less than 15 percent of the world’s proven reserves Fossil fuel usage has steadily increased since the Industrial Revolution At the start of the twenty-first century fossil fuels comprised nearly 90 percent of the world’s energy supplies However fossil fuels are nonrenewable resources Because it takes millions of years for fossil fuels to form they cannot be replaced when they are used Burning petroleum and coal releases harmful gases such as carbon monoxide nitrogen oxide and sulfur dioxide These gases pollute the air and react 6
INTRODUCTION Before they can be used fossil fuels must be extracted from the ground This beam-pumping unit on top of an oil well is used to lift oil up to the surface with moisture in the atmosphere to create acid rain Scientific evidence shows that burning fossil fuels increases atmospheric temperatures This warming of Earth’s atmosphere called the greenhouse effect contributes to climate change a serious environmental environmental concern 7
