Various sources of energy can be used to power human activities, and often this energy must be transferred from source to destination.

Teaching about energy sources is supported by 7 key concepts:

4.1 Humans transfer and transform energy from the environment into forms useful for human endeavors. The primary sources of energy in the environment include fuels like coal, oil, natural gas, uranium, and biomass. All primary source fuels except biomass are non-renewable. Primary sources also include renewable sources such as sunlight, wind, moving water, and geothermal energy.

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4.2 Human use of energy is subject to limits and constraints. Industry, transportation, urban development, agriculture, and most other human activities are closely tied to the amount and kind of energy available. The availability of energy resources is constrained by the distribution of natural resources, availability of affordable technologies, socioeconomic policies, and socioeconomic status.

4.3 Fossils and biofuels are organic matter that contains energy captured from sunlight. The energy in fossil fuels such as oil, natural gas, and coal comes from the energy that producers such as plants, algae, and cyanobacteria captured from sunlight long ago. The energy in biofuels such as food, wood, and ethanol comes from the energy that producers captured from sunlight very recently. Energy stored in these fuels is released during chemical reactions, such as combustion and respiration, which also release carbon dioxide into the atmosphere.

4.4 Humans transport energy from place to place. Fuels are often not used at their source but are transported, sometimes over long distances. Fuels are transported primarily by pipelines, trucks, ships, and trains. Electrical energy can be generated from a variety of energy resources and can be transformed into almost any other form of energy. Electric circuits are used to distribute energy to distant locations. Electricity is not a primary source of energy, but an energy carrier.

4.5 Humans generate electricity in multiple ways. When a magnet moves or magnetic field changes relative to a coil of wire, electrons are induced to flow in the wire. Most human generation of electricity happens in this way. Electrons can also be induced to flow through direct interaction with light particles; this is the basis upon which a solar cell operates. Other means of generating electricity include electrochemical, piezoelectric, and thermoelectric.

4.6 Humans intentionally store energy for later use in several different ways. Examples include batteries, water reservoirs, compressed air, hydrogen, and thermal storage. Storage of energy involves many technological, environmental, and social challenges.

4.7 Different sources of energy and the different ways energy can be transformed, transported, and stored each have different benefits and drawbacks. A given energy system, from source to sink, will have an inherent level of energy efficiency, monetary cost, and environmental risk. Each system will also have national security, access, and equity implications.

The topic of energy sources may be one of the defining issues of our students' lives

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As oil resources become more scare, exploration pushes the boundaries of what is technologically possible, such as drilling in deep offshore waters.

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The origins of our energy supply is an exciting and engaging topic for students and is an excellent way to learn about different ways that energy can be generated, as well as the impacts and societal implications of various types of energy. These concepts revolve around energy that is used for human purposes, including renewable and nonrenewable sources of energy, storage of energy, generation of electricity, and transportation of energy from place to place.

An essential starting place for this topic is the concept of renewable vs. non-renewable energy sources. Many students will already be familiar with the idea that fossil fuels regenerate at a rate far slower than we use them, which is why they are non-renewable. Renewable energy comes in many forms: hydroelectric, solar, wind, geothermal, and biofuels. Each of those offers a host of related topics and nuances. For example, solar energy can be generated on a single rooftop or in large, utility-scale solar farms. Solar energy can also be generated in concentrating solar power plants that use an array of mirrors to direct the Sun's energy to a central tower. This type of solar power can deliver energy even at night. A detailed study of energy generation can prevent overly simplistic labeling of particular types of energy as good or bad.

It's also worthwhile to address the practical and technological aspects of energy. The distribution of energy resources across the globe is uneven, as some regions have an abundance of energy sources while others do not. The areas where energy is used most intensively are not necessarily the same places where energy resources naturally exist. For example, rich oil and gas deposits are found in offshore marine environments and wind farms are located in rural settings. In both cases, this energy is transported to a location where the energy is consumed. Moreover, the end uses of energy vary with geography, time of year, and time of day. Thus energy needs to be transported, stored, and converted from one form to another so that it is available when and where it is needed.

Learning about energy sources offers real-world lessons

Just as ecosystems depend on the input of energy, human societies are also dependent on energy for infrastructure, transportation, food, and most other types of human activities. However, there are limits to how much energy is available to a given society. Even renewable forms of energy are dependent on geographic location and technological accessibility. Nonrenewable energy supplies are finite and create impacts from their extraction, transportation, and consumption. Energy pricing, energy equity, and energy security are all factors that dictate how readily energy is available to different parts of society. Some societies have an abundance of energy while others struggle to have their basic needs met. By learning about these concepts students can begin to see how humans are dependent on using energy but are also constrained by the practicalities of energy use.

Helping students understand these ideas

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This image contains information by the U.S. Energy Information Administration (EIA) that shows a breakdown of energy consumption as a function of the different types of energy sources. This image is updated yearly so the most up-to-date information can be found at: https://www.eia.gov/energyexplained/us-energy-facts/

This illustrates the extraordinary challenges we face in moving beyond fossil energy. Transitioning away from fossil fuels brings about a new set of questions such as energy storage, battery technology, and an energy supply that is knit together from numerous intermittent sources rather than a few, steady-state power plants.

Today's students are likely to be enthusiastic about renewable energy, which is a great way to get them engaged. But they must learn about the challenges and realities of overhauling the energy system. For example, consider the vast installations of renewable energy it will take to replace the 79% of the energy supply that comes from fossil fuels, and the logistics of where to locate wind turbines, solar farms, or other new energy infrastructure. Numbers are important. A quantitative treatment of these subjects makes it clear that we have a long way to go in securing a dependable, safe, and clean energy supply.

Bringing these ideas into your classroom

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Energy is part of every student's life and is used all around us. Therefore it is easy to find relevance in teaching about energy sources. The activity Power Source, asks teams of students to create a concept sketch of electricity that begins at their light switch and trace it back as far as they can go. This activity can be used with any grade level and it serves as an introductory activity that can prompt further exploration and can also reveal misconceptions. Students can take this concept further and design their energy portfolios based on internet research about various energy sources.

Students could also examine cutting-edge energy innovations such as solar roof shingles, energy from algae, or novel ways to store energy. Nearly every day we learn of a new possibility. The flip side of this is that it can be hard for educators to keep pace with the rapid changes. For example, renewable energy prices are falling every year, and renewable energy installations are outpacing projections all around the world. Educators need to be mindful to present up-to-date information, which may involve checking and updating figures every year. The Energy Information Administration offers an abundance of data, maps, graphs, and forecasts that can be used to investigate several questions.

Teaching materials from the CLEAN collection

Middle school

• Energy Production by Country describes global and regional energy production.
• Algal Biofuels: An Emerging Renewable Energy - students explore the basic living requirements of algae (phytoplankton) through hands-on experience and an interactive game.
• Oceans of Energy focuses on ocean exploration as a way to learn how to capture, control, and distribute renewable ocean energy resources. Students research one ocean energy source using the internet, then build a micro-hydroelectric generator.

High school

• The Great Energy Debate allows student teams to develop key points on the pros and cons of their assigned energy source and compare it to others.
• The United States of Energy is an engaging, interactive map and database that illustrate energy production and consumption in different states. Useful for student-driven internet research, or comparing energy in different states.
• Wind Maps is a map of the mean annual wind speed 80 meters above the ground. This map can be used to evaluate the potential for wind energy in the US.

College

• Wind Energy Using Google Earth uses seven large wind farms scattered over the globe to compare the potential wind resource capacity of each farm.
• Our Energy System is an interactive diagram from the National Academy of Sciences that shows how we rely on a variety of primary energy sources to supply energy to four end-use sectors (residential, commercial, industrial, and transportation).
• Electricity data browser contains up-to-date data on electricity generation in the US. Data can be filtered and graphed in multiple ways and is useful for inquiry-driven lessons about energy generation.
• Natural Gas and the Marcellus Shale uses a case study approach to learning about hydraulic fracturing.
• Selecting Sites for Renewable Energy Projects uses Google Earth to investigate a variety of renewable energy sources and to select sites within the United States that would be appropriate for renewable energy development.