7.3: Powering the United States

Last updated
Save as PDF

Page ID: 198474

\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

Learning Objectives

Determine if an energy source is renewable or nonrenewable.
Realize what sources provide the most power for the United States.
Compare and contrast the different types of energy sources.
Understand the environmental impacts of energy sources.
Compare and calculate the amounts of energy produced from each source (using Kilo, Mega, and Giga units)

Source of Energy

Production of electricity can involve either one of two primary energy sources. For example, a country employs nonrenewable sources like natural gas, petroleum, coal, or nuclear energy to supply power to homes and industry. In addition, an area might choose to incorporate renewable energy sources to meet its consumers' needs. Examples of these would include biomass, hydropower, geothermal, wind, and solar energies.

electrical energy in the united states 2020.jpg — Figure \(\PageIndex{5}\): Chart illustrating electrical power generation in the United States. Image is taken from Electricity in the U.S. - U.S. Energy Information Administration (EIA)

As of 2020, the current United States population is approximately 331 million people. Supplying electricity to a population of this size requires many different types of sources. At this time, the majority of electrical output is the result of fossil fuel combustion. Click on this link to see how energy sources used in the United States have changed over the years.

Energy Units

The SI unit for heat is the Joule. Heat can also be measured using the unit calories. One calorie (this unit is not equivalent to the calorie seen in foods) is equivalent to 4.184 Joules. The table below illustrates the amount ot heat that can be produced from the burning of a specific material. Capital M is representative of the metric unit, mega. The one gas in the table below is measured using the volumetric term of meters cubed (m³). Lastly, the other substance amounts correlate per kilogram of material burned.

Table \(\PageIndex{2}\): Energy Conversion: Typical Heat Values of Various Fuels (units are Megajoule/kilogram)
Firewood (dry)	16 MJ/kg
Brown coal (lignite)	10 MJ/kg
Black coal (low quality)	13-23 MJ/kg
Black coal (hard)	24-30 MJ/kg
Natural Gas	38 MJ/m³
Crude Oil	45-46 MJ/kg
Uranium - in a typical reactor	500,000 MJ/kg (of natural U)

Coal

In the United States, coal is the cheapest option as an electrical source. The coal industry estimates that there are approximately 260 billion tons of coal yet to be mined in this country. Assuming the daily rate of coal consumption remained constant, the United States should have enough coal reserves to last over 230 years. Annually, The United States produces over one billion tons of coal. This value equates to approximately 12% of the world's supply.

Heavy equipment is utilized to extract coal from the surface of the earth. Surface mining can lead to residual chemicals from the coal entering the water supply and surrounding soils. Many states, namely West Virginia and Pennsylvania, still use coal miners to dig coal from underground reserves. Although regulated, this occupation can be particularly risky with exposure to particulate chemicals that can affect the lung and hearts of workers. In addition, gaseous chemicals inside the mine can combust easily if a spark is present. This could result in trapped workers and fatalities at the site.

There are 600 coal-burning electric plants in the US delivering \(44.9\%\) of American electricity and producing 2 billion tons of \(\ce{CO_2}\) annually, accounting for \(40\%\) of U.S. \(\ce{CO_2}\) emissions and \(10\%\) of global emissions. Coal-burning facilities also produce \(64\%\) of the sulfur dioxide emissions, \(26\%\) of the nitrous oxide emissions, and \(33\%\) of mercury emissions. Sulfur dioxide and nitrous oxide combustion are precursors to acid rain and industrial and photochemical smog. Mercury, a heavy metal toxin, affects the neurological system and can cause behavior and intellectual disorders. Incomplete combustion of carbon can produce particulate matter. These carbon-based solids gather in the atmosphere and make visibility difficult. For more information about combustion of any type of fossil fuel, click on this link.

Trace amounts of radionuclides can be detected in coal. Uranium and thorium isotopes that are present will eventually decay to other species. When burned, these substances become airborne and release their decay products. All chemicals and matter resulting from the combustion process can cause heart, lung, and immunity disorders. In addition, high combustion areas can affect the average lifespan of individuals and species living in these areas.

download (2).jpg — Figure \(\PageIndex{7}\): Two pictures of Beijing in 2005. The picture on the left shows the city after two days of rain. The picture on the right shows smog gathering in the atmosphere.

Coal can be cleaned to remove some impurities (like sulfur-based species), but there is no such thing as "clean" coal. Industries that burn coal can install scrubbers in their smokestacks to grab many pollutants before they enter the atmosphere. In the United States, the Environmental Protection Agency (EPA) regulates all pollutants resulting from the combustion process except for carbon dioxide.

Natural Gas

Natural gas combustion does not produce as many types of byproducts. It is a much cleaner fuel to burn and there would be fewer environmental and health problems related to this fuel choice. Greenhouse gases are still produced when this fuel is burned. Unfortunately, natural gas exists deep within the ground and can be difficult to extract.

alt — Figure \(\PageIndex{8}\): Natural gas reserves in the United States. Image is taken from https://c1.staticflickr.com/9/8743/1...08652510_z.jpg

Hydroelectric

Hydroelectric sources provide almost 7% of the United State's electricity. To use this type of energy, a large body of water needs to be present within the area. A river is intentionally dammed to create a large water supply. With monitored releases, the dammed water is allowed to fall to a lower altitude. This motion will turn a turbine which will produce energy. Unlike fossil fuel combustion, hydroelectric sources do not release toxins into the atmosphere. As a result, this method of energy production does not contribute to global warming, acid rain, or smog production. Some disadvantages of hydroelectric power include the disruption of aquatic ecosystems. Construction of hydroelectric facilities requires large areas of land that could involve uprooting and affecting human and animal populations. Lastly, altering land geology can cause severe flooding.

The largest hydroelectric facility in the United State is located in Washington State along the Columbia River. Grand Coulee Dam produces over 6800 Megawatts of electrical energy for this region of the country. At this time, there are over 1600 hydroelectric plants in the United States.

Figure \(\PageIndex{9}\): Arial view of Grand Coulee Dam. The image is taken from upload.wikimedia.org/wikiped...Dam_aerial.jpg

Solar and Wind Power

In recent years, the use of wind and solar sources has increased in this country. Both of these types of energy require large plots of land for their structures. In addition, both the sun and wind need to be present to generate energy. Wind and solar energy can be stored for days in which the climate does not produce adequate amounts of either. With wind energy, there is some concern about how the structures appear and affect wildlife. These devices can also be very noisy. At this time, Texas leads the country in the production of wind energy.

Research has focused on making components of solar panels less toxic and more affordable for the average consumer. Many utility companies offer incentives for residents to install solar panels. In addition, some utility companies will buy back excess solar wattage from their own consumers. The state of California leads the country in the production of solar energy. The Ivanpah Solar Farm in the Mohave Desert generates over 390 megawatts of energy per year.

download (1).jpg — Figure \(\PageIndex{10}\): Ivanpah is the largest solar farm in the United States in California. The image is taken from upload.wikimedia.org/wikiped...ity_Online.jpg

Recently, Furman University installed its own solar farm. Click on this link to read more about how this university is using renewable energy to cut down on carbon emissions.

Nuclear Reactors

There are over thirty countries that use nuclear power to generate electricity. Commercial nuclear reactors can be found in North and South America, Europe, Africa, and Asia. The United States has the most reactors of any other country. There are around ninety-nine reactors in the United States that provide around twenty percent of the electrical energy in the United States. Other countries, like France, employ around sixty nuclear reactors to produce 80% of their electrical power.

Table \(\PageIndex{1}\): Nuclear Share of Electricity Generation in 2016. Data from the International Atomic Energy Agency
Country	Number of Operated Reactors	Total Net Electrical Capacity	[MW]Nuclear Electricity Supplied	[GW.h]Nuclear Share
FRANCE	58	63130	386452.88	72.3
SLOVAKIA	4	1814	13733.35	54.1
UKRAINE	15	13107	76077.79	52.3
BELGIUM	7	5913	41430.45	51.7
HUNGARY	4	1889	15183.01	51.3
SWEDEN	10	9740	60647.40	40.0
SLOVENIA	1	688	5431.27	35.2
BULGARIA	2	1926	15083.45	35.0
SWITZERLAND	5	3333	20303.12	34.4
FINLAND	4	2764	22280.10	33.7
ARMENIA	1	375	2194.85	31.4
KOREA, REPUBLIC OF	25	23077	154306.65	30.3
CZECH REPUBLIC	6	3930	22729.87	29.4
SPAIN	7	7121	56102.44	21.4
UNITED KINGDOM	15	8918	65148.98	20.4
UNITED STATES OF AMERICA	100	100351	804872.94	19.7
ROMANIA	2	1300	10388.20	17.1
RUSSIA	36	26496	184054.09	17.1
CANADA	19	13554	95650.19	15.6
GERMANY	8	10799	80069.61	13.1
SOUTH AFRICA	2	1860	15209.47	6.6
MEXICO	2	1552	10272.29	6.2
ARGENTINA	3	1632	7677.36	5.6
PAKISTAN	4	1005	5438.90	4.4
CHINA	36	31384	197829.04	3.6
INDIA	22	6240	35006.83	3.4
NETHERLANDS	1	482	3749.81	3.4
BRAZIL	2	1884	14970.46	2.9
JAPAN	43	40290	17537.14	2.2
IRAN	1	915	5923.97	2.1

Today's nuclear power plants use fission reactions to generate energy for electrical production. One kilogram of U-235 can supply over 2.4 x 10⁷ kilowatt-hours (kWh) of energy. In contrast, one kilogram of coal can only produce 8 kilowatt-hours of energy. Also, nuclear does not contribute to the problems of acid rain, smog, or greenhouse gas production.

uranium pellet.jpg — Figure \(\PageIndex{11}\): Nuclear power fuel pellet (Copyright; Southern Nuclear Company)

Nuclear and coal power plants can appear similar to most people. Both of these types of facilities have large cooling towers that release excess steam energy into the atmosphere. Nuclear power plants will have small, round, and dome-like structures to house the nuclear reactors. In contrast, coal-fired plants will have slender chimney stacks that tower above or at the rounder cooling towers.

Figure \(\PageIndex{12}\): (left) View of Vogtle Nuclear Power Plant (Units 1 and 2) in Augusta, Georgia produces approximately 2.3 gigawatts of power a year. (right) The *Bruce Mansfield Coal Fire Plant in Shipping Port, Pennsylvania produces 2.4 gigawatts of energy a year. Images* are taken from en.Wikipedia.org/wiki/Vogtle...Vogtle_NPP.jpg and https://3.bp.blogspot.com/-WycgHj-jt...eMansfield.jpg

alt — Figure \(\PageIndex{12}\): (left) View of Vogtle Nuclear Power Plant (Units 1 and 2) in Augusta, Georgia produces approximately 2.3 gigawatts of power a year. (right) The *Bruce Mansfield Coal Fire Plant in Shipping Port, Pennsylvania produces 2.4 gigawatts of energy a year. Images* are taken from en.Wikipedia.org/wiki/Vogtle...Vogtle_NPP.jpg and https://3.bp.blogspot.com/-WycgHj-jt...eMansfield.jpg

Sources

en.Wikipedia.org/wiki/Shippi..._Power_Station
https://www.census.gov/popclock/
http://www.hydro.org/policy/faq/#494
www.euronuclear.org/info/enc...comparison.htm
https://pubs.usgs.gov/fs/1997/fs163-97/FS-163-97.html
Paul Flowers (University of North Carolina - Pembroke), Klaus Theopold (University of Delaware) and Richard Langley (Stephen F. Austin State University) with contributing authors. Textbook content produced by OpenStax College is licensed under a Creative Commons Attribution License 4.0 license. Download for free at http://cnx.org/contents/85abf193-2bd...a7ac8df6@9.110).