ERC: Lesson - Fossil Fuels (Topic 6.5) đź“–

⏳ Estimated Reading Time: 11 - 13 minutes

Learning Objective

Describe the use, methods, and effects of fossil fuels in power generation.

 

Energy Generation from Fossil Fuels


A power plant with tall stacks, from which dark smoke is billowing against a cloudy sky. Superimposed on the smoke are blue circles containing chemical symbols for various pollutants such as lead (Pb), nickel (Ni), sulfur dioxide (SO2), iron (Fe), arsenic (As), and selenium (Se), indicating the types of pollutants that may be emitted from such facilities.
Burning fossil fuels produces SPM and SO2.

The combustion of fossil fuels is a process that converts stored chemical energy in the fuels into thermal energy, which can be used for various purposes such as generating electricity, heating, or transportation. Fossil fuels are mainly composed of carbon and hydrogen atoms.

When fossil fuels are burned in the presence of oxygen, they react with the oxygen molecules and produce carbon dioxide and water as the main products, along with other pollutants such as sulfur dioxide (SO2), nitrogen oxides (NOx), and particulate matter (also known as suspended particulate matter or SPM), which are tiny particles left over from the burning process. The reaction releases a large amount of heat. The general equation for the combustion of a hydrocarbon fuel is:

For example, the combustion of methane, the main component of natural gas, can be written as:

LaTeX: CH_4+2O_2\Longrightarrow CO_2+2H_2O+HeatCH4+2O2âźąCO2+2H2O+Heat

 

Essential Knowledge

The combustion of fossil fuels is a chemical reaction between the fuel and oxygen that yields carbon dioxide and water and releases energy.

 

Energy from fossil fuels is produced by a process called thermal power generation, which involves converting the chemical energy stored in the fuels into electrical energy.

 

The process of a coal-fired power plant. It includes labeled components such as a coal conveyer, boiler, turbine, generator, transformer, and cooling tower, all connected to show the flow from coal input to electricity and heat output.
Thermal Power Generation involves burning fossil fuels to produce heat.

When it comes to energy generation from fossil fuels, it's all about harnessing the power of burning these fuels to create heat. This heat is used to turn water into steam. The steam then spins a turbine, kind of like a giant fan, which in turn generates electricity. It's like a big, fiery chain reaction that ultimately lights up our homes and powers our devices. 

 

Essential Knowledge

Energy from fossil fuels is produced by burning those fuels to generate heat, which then turns water into steam. That steam turns a turbine, which generates electricity.

 

Fossil Fuel Extraction


Fossil fuels, such as coal, oil/petroleum, and natural gas, are essential sources of energy that power our daily lives. But have you ever wondered how these fuels are extracted from the earth? Explore the tabs below to learn more about how we extract each type of fossil fuel from the Earth:

 

Coal Extraction

 a large mining truck in motion at an active mining site.
Mining removes large amounts of rock to expose coal deposits.

Coal is typically mined through two main methods: surface mining and underground mining.

In surface mining, large machinery, such as bulldozers and excavators, are used to remove layers of soil and rock to expose the coal seams.

On the other hand, underground mining involves digging tunnels deep into the earth to access the coal deposits. Once the coal is extracted, it is transported to processing plants for cleaning and refining.

Surface mining accounts for around 70% of our coal mining and underground mining accounts for the remaining 30%. Once it has been extracted from the ground, coal is broken into smaller pieces, and shipped by train or truck to its ultimate destination. In the United States, about 88% of coal is used to heat water in power plants to produce electricity. 

Refer back to the Mining Lesson in the Land and Water Use Module for more detailed information about mining.

 

 

Essential Knowledge

Humans use a variety of methods to extract fossil fuels from the earth for energy generation.

 

Environmental Effects of Fossil Fuels


Using fossil fuels as the main source of energy in society has led to a number of significant environmental issues. There are many issues surrounding the production of fossil fuels. 

The tabs below touch on some of the most important and wide-reaching issues associated with extraction, transportation, processing, and combustion of fossil fuels. Are there any impacts that you were unaware of? Which do you think is the most important? Why?

Extraction

an oil pump jack, prominently colored in blue and red, operating in a field under a cloudy sky.
Extracting fossil fuels disrupts the environment.

Coal

Mining or drilling for fossil fuels can disturb or disrupt habitats on land and in the ocean. When these habitats are disrupted, the species that live in these environments can suffer. For example, mountaintop removal of coal completely destroys mountaintops. Extracting fossil fuels from the environment also negatively impacts the aesthetics (beauty) of the environment.

Coal production produces quite a bit of pollution. Coal is located in veins of rock that can be as wide as 30 meters. Coal is hazardous to mine and dirty to handle. Miners often get a disease from mining coal known as black lung, or coal workers’ pneumoconiosis (CWP), from inhaling coal dust.  Surface mining accounts for 69% of our coal mining and underground mining accounts for the remaining 31%. Once it has been extracted from the ground, broken into smaller pieces, and shipped by train or truck to its ultimate destination. 

Oil/Petroleum

When attempting to mine or drill for coal and petroleum, pockets of natural gas are exposed. The gas may be captured directly or simply flared (burned) off as a nuisance.

Natural Gas

Hydraulic fracturing (“fracking”) for natural gas uses a large amount of water. When the water is used in fracking, the quality of the water is degraded, which means the water can no longer be used.

The waste products of fracking must be disposed of in special wells deep in Earth’s crust, which has been implicated in causing earthquakes.

The number and distribution of earthquakes with a magnitude greater than 3 in the Central US from 1973 to 2020. The map shows the Central US with earthquakes represented by dots, concentrated mainly in Oklahoma. The bar graph illustrates a significant increase in earthquakes after 2008, with 867 earthquakes from 1973-2008 and 3804 from 2009-2020.
Earthquakes in the Central United States have increased significantly since we have started fracking in those areas.

In the central United States, where there has been a lot of fracking, earthquakes have significantly increased in frequency compared to historical activity. More research is being done into this process to try to lower the occurrence of fracking-related earthquakes.

 

 

Essential Knowledge

Hydrologic fracturing (fracking) can cause groundwater contamination and the release of volatile organic compounds. 

 

Mitigating the Effects of Fossil Fuel Use


an illustrative diagram of an electrostatic precipitator.
Electrostatic precipitators reduce air pollution from power plants, but they are expensive to install. These costs are eventually passed onto the consumer (us).

To reduce the negative impacts of fossil fuel combustion, some possible solutions include improving the efficiency of energy use, developing alternative and renewable energy sources, implementing carbon capture and storage technologies, and promoting conservation and sustainability practices.

The EPA now requires significant amounts of air pollution control equipment on power plants, vehicles, and other users of fossil fuels.

For example, power plants are often required to install equipment like Cyclone Separators, Fabric Filters, Cartridge Filters, Electrostatic Precipitators (ESPs), High-Efficiency Particulate Air (HEPA) Filters, Venturi Scrubbers, and Fiber-Bed Mist-Eliminators. Additionally, for controlling nitrogen oxides, technologies such as Selective Non-Catalytic Reduction (SNCR) or Selective Catalytic Reduction (SCR) may be required.

The Clean Air Act đź’¨ mandates that vehicles have emission control systems, which include catalytic converters and evaporative emission control systems to reduce harmful emissions.

All this pollution-prevention equipment is expensive. Companies do not want to spend more than they have to when producing or burning fossil fuels because it either decreases their profits or forces them to increase prices for the consumers.  And consumers do not want to spend more than they have to for fuel, so they do not want prices to increase either.

In either case, reducing pollution from burning fossil fuels increases the costs paid to use fossil fuels. The short story is that if we want a cleaner atmosphere, we need to be willing to pay a higher monetary cost for it.

Fossil fuels have helped shape society for several hundred years. The environmental and health costs associated with using them have led to more research and development of alternative energies. As we continue to use up the finite supply of fossil fuels on Earth, the move to renewable energies will accelerate.

 

AP Exam Tip

You should know the basics of how fossil fuels are extracted from the Earth.

You should know some mitigation strategies for reducing the environmental impacts of fossil fuels.

 

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