7.7: Electric Power Generation
- Page ID
- 123064
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Fossil fuels may be used directly for their energy content. For example, gasoline is used directly in automobiles; natural gas is used for heating, cooking, transportation, etc. However, in many cases, the primary energy source is not in a usable form for the end-use energy consumer. Approximately one-third of the U.S. energy consumed is in the form of electricity. Except for photovoltaic energy produced from the solar energy, electrical energy is produced indirectly from primary sources such as fossil fuels. The amount of electrical energy produced from various primary sources is shown in Table \(\PageIndex{1}\). Fossil fuels made up 60% of the primary energy sources for producing electricity in the U.S. in 2023.
| Energy source | Billion kWh | Share of total |
|---|---|---|
| Total - all sources | 4,178 | |
| Fossil fuels (total) | 2,505 | 60.0% |
| Natural gas | 1,802 | 43.1% |
| Coal | 675 | 16.2% |
| Petroleum (total) | 16 | 0.4% |
| Petroleum liquids | 12 | 0.3% |
| Petroleum coke | 5 | 0.1% |
| Other gases3 | 11 | 0.3% |
| Nuclear | 775 | 18.6% |
| Renewables (total) | 894 | 21.4% |
| Wind | 425 | 10.2% |
| Hydropower | 240 | 5.7% |
| Solar (total) | 165 | 3.9% |
| Photovoltaic | 162 | 3.9% |
| Solar thermal | 3 | 0.1% |
| Biomass (total) | 47 | 1.1% |
| Wood | 31 | 0.8% |
| Landfill gas | 8 | 0.2% |
| Municipal solid waste (biogenic) | 6 | 0.1% |
| Other biomass waste | 2 | 0.1% |
| Geothermal | 16 | 0.4% |
| Pumped storage hydropower4 | -6 | -0.1% |
| Other sources5 | 10 | 0.2% |
Table \(\PageIndex{1} \): U.S. utility-scale electricity generation by source, amount, and share of total in 2023. Source US Energy Information Administration.
Electromagnetic Induction
In order to produce electricity, one must employ the laws of electromagnetism. Recall the steam-cycle power plant from Section 7.2.1. The primary energy source could be any fossil fuel that produces heat to create steam. The objective is to rotate a turbine connected to an electrical generator.
Figure \(\PageIndex{2}\): Diagram of a typical steam-cycle coal power plant (proceeding from left to right). Image by US Tennessee Valley Authority – Public domain. www.tva.com
When the generator is turned, electricity is produced due to Faraday's Law of Induction. A diagram of an electric generator is shown in Figure \(\PageIndex{3}\).
Figure \(\PageIndex{3}\): An electric generator with rotating coils of wire and static magnets. The relative motion of the coils and magnets produces electricty due to Faraday's Law of Induction. Source https://www.quora.com/What-is-the-use-of-a-magnet-in-an-electric-motor.
Bar Magnet
Click on the "Bar Magnet" tab and explore to determine answers to these questions.
- How does the compass indicate the direction and magnitude of the magnet's field?
- How does changing the magnet's strength change the visual representation in the simulation?
- How does the field direction inside the magnet compare to outside of the magnet?
Pickup Coil
Click on the "Pickup Coil" tab and explore to determine answers to these questions.
- What is required of the magnet to cause charge flow (current) in the loops and light to be emitted?
- Is the brightness of light dependent on how you created light in the question above? Explain.
- What do you think the brightness of the light is indicating?
- How do magnet strength, number of coil loops, area of coil loops affect the amount of light? For example, you might say that the brightness of light produced is proportional to the area of the loops.
Electromagnet
Click on the "Electromagnet" tab and explore to determine answers to these questions.
A battery now pushes current through the coils of wire, and no bar magnet exists. However, the compass reacts to the coils.
- How does the battery voltage affect the compass behavior?
- Is the coil a magnet only under certain circumstances related to voltage?
- What does changing to a negative voltage do? You may want to review the "Bar Magnet" tab to be specific about north and south poles.
- How does the number of loops affect the magnetic behavior of the coil?
Generator
Click on the "Generator" tab and explore to explain the requirements to maximize the energy output of a hydropower plant. How is this simulation related to Figures \(\PageIndex{2}\) and \(\PageIndex{3}\)?