Fossil Fuels
The nonrenewable way of energy use.
Fossil fuels are formed from decaying plant life millions of years ago. The process of decaying matter releases energy and reverses photosynthesis. It produces CO2 and H2O.
Reverse Photosynthesis
C6H12O6 + 6O2 → 6CO2 + 6H2O + energy
Fossil fuels take time to develop. At the rate that fossil fuels are used, it is not sustainable for future energy needs. They cannot be replaced in useful time. Though they cannot be replaced within useful time, the energy they produce cannot be created or destroyed, following the first law of thermodynamics. Energy is reused and contained in different forms after its release. There is no way to create or destroy energy, it simply exists and is repurposed as it is needed.
Nonrenewable energy includes coal, petroleum products, and natural gas.
Nonrenewable Energy
Coal
Coal is composed of pure carbon and a mixture of small amounts of other elements. Its chemical formula is represented as C 135H96O9NS. The molecule is 85% carbon. This high percentage of carbon and a lower percentage of oxygen create a better fuel.
The process of obtaining coal is dangerous and expensive. Coal is obtained by mining. The action of mining is dirty, as it endangers human health, causes environmental harm, and contributes to pollution. Underground mining has killed over 100,000 workers and many others have adverse health effects. Mineshafts have also been a problem for groundwater. Groundwater infiltrates abandoned mineshafts and comes in contact with sulfur-rich rock from coal deposits. The water exposed to the sulfur-rich rock becomes acidified and uninhabitable. In 2005 the United State Environmental Protection Agency estimated that more than 700 miles of Appalachian streams were completely buried as a result of mountaintop mining between 1985-2001. The process of mining affects thousands of ecosystems through its pollution output.
Coal is considered a dirty fuel both physically and combustion-wise. In the 19th and 20th centuries, soot from coal fires blackened buildings and lungs. In Pittsburgh, Pennsylvania in the mid-1940s, steel mills, using coal to generate energy, generated enough atmospheric pollution to mask the mid-day sun. Though filters and precipitators are used to aid with coal contamination in coal-burning plants, coal is still a threat to the environment and workers in coal factories.
Petroleum (Crude Oil)
The use of coal diminished as the production and use of oil increased. Petroleum or crude oil has the advantage of being a liquid. The collection of petroleum is easier than the collection of coal as it can be pumped to the surface and transported with ease. In comparison to coal, crude oil produces between 40% and 60% more energy. Petroleum quickly became the more efficient and preferred energy source after its exploitation in the early 1900s.
The consumption rate of oil currently topples its current production rate. Around 91 million barrels of oils are consumed per day while only about 87 million barrels are produced per day. In the mid-1950s the average global consumption of oil was about 8 million barrels per day and the production of oil was about 15 million per day. The world consumption ratio must be fixed to ensure sustainable levels of extraction and use.
Oil is found within pores of geologic rock formations, such as sandstone. Oil is collected through the process of fracking. Fracking or hydraulic fracturing is the action of injecting fluid at a high enough pressure to push crude oil and natural gas to the surface. The higher the porosity of the rock, the higher the potential for oil storage within the rock. The rock must contain some permeability for the oil to flow.
The action of obtaining petroleum impacts the environment through water contamination, air emissions, climate change, and health risks to animal and human life.
Natural Gas
Natural gas is composed mostly of methane (CH4). Natural gas provides heat for more than half of the homes in the United States. Heat for natural gas is furnished directly at the home or via electricity produced by burning natural gas at a power plant. Natural gas is relatively clean. It produces fewer chemicals and carbon dioxide in comparison to crude oil and coal.
Like the extraction of petroleum, natural gas is collected through fracking. Fracking or hydraulic fracturing is the action of injecting fluid at a high pressure to push natural gas and crude oil to the surface. This action drills down into the gas or oil-bearing rocks that are 1-3 miles beneath Earth’s surface. Rocks with low permeabilities, or porous rock, increase the rate of recovery of natural gas and crude oil.
The action of obtaining natural gas impacts the environment through water contamination, air emissions, climate change, and health risks to animal and human life.
The Process of Combustion
The purpose of fossil fuels is to generate energy. Energy can be created by the generation of fire. To create fire, there is a need for heat, fuel, and an oxidizer. A fire will continue to burn until the oxygen or fuel is removed. In a closed environment, fire will subside when all the oxygen is gone. The addition of oxygen may cause a backdraft. A backdraft occurs when there is an addition of oxygen to an oxygen-depleted fire causing an explosion. Oxygen (O2) is the most typical oxidizing agent.
Fuel + Oxidizer + Heat → Products
Sustainability
Fossil Fuels, or nonrenewable energies, are considered to be dirty fuels, both physically and combustion-wise.
Coal produces blackened soot which is harmful to ecosystems, man-made structures, and human health. Coal combustion also produces more CO2 per kilojoule of heat released than petroleum or natural gas. This abundance of carbon dioxide contributes to acid rain. Acid rain is any form of perception that is supersaturated with hydrogen ions. These ions contribute to nitric acid and sulfuric acid build-up in the atmosphere that is then released into the environment through rain, snow, hail, or sleet. The development of clean coal technology aims to increase the efficiency of coal using power plants and decrease the harmful emission of coal.
Petroleum and natural gas pose a large threat to underground contamination. The process of fracking, though efficient, traps a majority of the resources within rock sediment. This trapped oil or natural gas is unsustainably difficult and expensive to extract. Both time and money are spent looking for oil reservoirs and with the rate of consumption throughout the world, oil and natural gas become an economic and ecological burden. Once the readily available sources or sites for oil and natural gas are depleted, there will only be unconventional sources or sites in difficult locations.
Natural gas produces less CO2 than all other forms of fossil fuels. This is the most sustainable resource in comparison to the others explored in this module. Though it is more sustainable, there is still a deficit between production and consumption. Natural gas is not sustainable, just as coal and oil are not. The production of natural gas is much lower than the consumption rate of natural gas. Due to the time needed to create natural resources, such as coal, crude oil, and natural gas, this rate of consumption makes these nonrenewable resources unsustainable.
The waste produced due to combustion harm and effect the environment. These resources are large contributors to climate change, pollution, and the quality of future life.
