Each of the bullet points represent knowledge that you need to understand and apply to new scenarios. The bold numbers, such as 6.2, refer to the topics on AP Classroom. If you do not understand a topic, log into AP Classroom, and watch the AP Daily videos for that topic to review. The “More to know and understand” are details and types of questions you might see on your exam.

6.1 Identify differences between nonrenewable and renewable energy sources

Know:

Nonrenewable energy sources are those that exist in a fixed amount and involve energy transformation that cannot be easily replaced.
Renewable energy sources are those that can be replenished naturally, at or near the rate of consumption, and reused.

More to know and understand:

What are some examples of nonrenewable resources?

Coal, nuclear energy, oil, natural gas, uranium.

What are some examples of renewable resources?

Solar energy, wind, biomass, geothermal energy.

Can you describe something as renewable if it is reusable or recyclable? Why or why not?

Yes, renewable energy sources can also be reused.

Can renewable resources run out temporarily? Explain

No, renewable resources cannot run out temporarily because they are naturally replenished at a rate faster than they are consumed.

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6.2 Describe trends in energy consumption

Know:

The use of energy resources is not evenly distributed between developed and developing countries.
The most widely used sources of energy globally are fossil fuels
As developing countries become more developed, their reliance on fossil fuels for energy increases.
As the world becomes more industrialized, the demand for energy increases.
Availability, price, and governmental regulations influence which energy sources people use and how they can use them.

More to know and understand:

What are BTUs, Watts, Therms and Joules and how are they used in calculating energy? Note: You do not need to memorize exact definitions nor conversions between them

BTUs, Watts, Therms, and Joules are unit measures of electricity. They are used to measure and calculate energy through multiplication of power and time to calculate the total amount of energy used.

Make sure you know these metric conversions with watts. You will NOT need to convert between energy units such as Joules to Watts.

How many Watts in a Kilowatt? 1,000 watts
How many Watts in a Megawatt? 1,000,000 watts
How many Kilowatts in a Megawatt? 1,000 kilowatts

Math Practice: Use the pie graph to calculate: If the US uses 99 quadrillion BTUs of energy each year, how many BTUs for transportation?

99/100x28 =27.72

Math Practice: If the US uses 99 quadrillion BTUs of energy in 2022, and are projected to use 143 quadrillion BTUs by 2050, what is the percent increase?

143/99=1.444.

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6.3 Identify types of fuels and their uses

Know:

Wood is commonly used as fuel in the forms of firewood and charcoal. It is used in developing countries because it is easily accessible.
Peat is partially decomposed organic material that can be burned for fuel.
Natural gas, the cleanest of the fossil fuels, is mostly methane
Crude oil can be recovered from tar sands, which are a combination of clay, sand, water, and bitumen.
Fossil fuels can be made into specific fuel types for specialized uses (ie, aviation fuel, motor vehicle fuel).
Cogeneration occurs when a fuel source is used to generate both useful heat and electricity.

More to know and understand:

🡪 The fossil fuel “oil” can also be called petroleum and crude oil. We can pump crude oil from the ground, mine petroleum from tar sands and extract petroleum from shale using fracking.

What is peat a precursor to? Under what conditions is it made?

Peat is partially decomposed organic matter(often ferns or other plants) found in wet, acidic ecosystems like bogs and moors.

What are the main grades of coal? Which has the highest level of carbon? Which is the best in terms of energy per volume? Which type of coal has the highest sulfur content?

Lignite, bituminous, and anthracite are the main grades of coal. Anthracite has the highest level of carbon. Anthracite is also the best in terms of energy per volume. Lignite also has the highest sulfur content.

What is an example of cogeneration?

In an apartment building, exhaust from a gas-powered electrical generator is captured to produce hot water to heat a swimming pool.

Why has coal in powerplants declined while natural gas has increased?

Coal has declined in power plants while natural gas has increased because natural gas is generally cheaper, has cleaner burning, and is more efficient than coal making it more economically viable

Which fuel causes deforestation?

Palm oil.

Which fossil fuel is the most consumed in the world for total energy? (and also most consumed for commercial energy?)

Oil is the most consumed in the world for total energy and also most consumed for commercial energy.

Which fossil fuel is the most consumed for electricity?

Coal is the most used for electricity generation

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6.4 Identify where natural energy resources occur

Know:

The global distribution of natural energy resources, such as ores, coal, crude oil, and gas, is not uniform and depends on the region's geologic history.

More to know and understand:

🡪Petroleum and natural gas are mainly ancient plankton in ancient oceans. Coal is ancient swamp trees.

Review coal mining and its impacts from Unit 5.

How is oil trapped underground? How does porosity and permeability of rock and soil layers trap oil?

Oil is trapped underground when it flows from its source rock into a reservoir rock. The reservoir must have high porosity and permeability in order for the oil to accumulate. The impermeable rock layer that trap the oil are called caprock.

Which energy sources are not derived directly nor indirectly from the sun?

Nuclear power and geothermal energy.

Where are the main coal deposits in the United States?

The main coal deposits in the US are located in the Appalachian Basin, Powder River Basin, and the Illinois Basin.

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6.5 Describe the use and methods of fossil fuels in power generation and the impact they have on the environment.

Know:

Combustion of fossil fuels is a chemical reaction between the fuel and oxygen that yields carbon dioxide, water, and released energy.
Energy from fossil fuels is produced by burning those fuels to generate heat, which then turns water into steam. That steam turns a turbine, attached to a generator, which converts the mechanical energy into electrical energy.
Humans use a variety of methods to extract fossil fuels from the earth for energy generation (oil drilling (land and offshore), fracking, etc.)
Fracking can cause groundwater contamination and the release of VOC’s.

More to know and understand:

In a coal/natural gas/nuclear power plant, energy is converted from thermal energy (combustion or nuclear fission)🡪 kinetic energy 🡪 mechanical energy (turbines) 🡪 electrical energy (generator)

🡪 Know how electricity is generated and the parts of power plant from your energy diagram packet.

Which is the cleanest fossil fuel to burn?

Natural gas as it produces the least amount of carbon emissions and air pollutants

What greenhouse gasses are emitted from burning fossil fuels?

Gases like carbon monoxide, methane and nitrous oxide

Which fossil fuels primarily are used in transportation?

Petroleum, as this produces other forms of fuel such as gasoline and

How is oil extracted with and without fracking?

Via drilling through rock layers and then pumping the deposit

What fuel is often next to crude oil and can be harvested as well?

Natural gas can be found next to crude oil specifically on top of it as they are both made by decaying plants placed under lots of pressure

What is bitumen? Where do we extract from?

We can extract bitumen via tar sands. They are extracted by heating lots of water and using the steam into the sand via pipes to melt the bitumen into a liquid that is then able to flow in a pipe

What is keratin? Where do we extract from?

Byproducts from biological resources. These are extracted via these byproducts for example by processing poultry

What are the risks with offshore drilling for oil?

For example is the carrying risk of oil spills and because of this affects the surrounding environment

What are the main problems with drilling for oil on land?

They disturb land and marine ecosystems

How does fracking work?

Fracking fluid like acids and water is pumped into a well at very high pressure to crack the rock even & allow natural gas to flow out

What are the environmental impacts of fracking?

There is the process of having wastewater and the release of the greenhouse gases that are extracted by fracking

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6.6 Describe the use and methods of nuclear energy in power generation and the impact they have on the environment

Know:

Nuclear power is generated through fission, where atoms of Uranium-235 which are stored in fuel rods, are split into smaller parts after being struck by a neutron. Nuclear fission releases a large amount of heat, which is used to generate steam, which powers a turbine and generates electricity.
Radioactivity occurs when the nucleus of a radioactive isotope loses energy by emitting radiation.
Uranium-235 remains radioactive for a long time, which leads to the problems associated with the disposal of nuclear waste.
Nuclear power generation is a nonrenewable energy source. Nuclear power is considered a cleaner energy source because it does not produce air pollutants, but it does release thermal pollution and hazardous solid waste.
Three-mile Island, Chernobyl, and Fukushima are three cases where accidents or natural disasters led to the release of radiation. These releases have had short and long-term impacts on the environment.
A radioactive element’s half-life can be used to calculate a variety of things, including the rate of decay and the radioactivity level at specific points in time

More to know and understand:

🡪 Know how nuclear power is generated and the parts of a nuclear power plant from your energy diagram packet.

Where does fission occur in a nuclear power plant?

Fission can occur in nuclear reactors

In what part of a nuclear power plant do accidents occur?

In Nuclear power plants, accidents occur in the reactor core since it can release a significant amount of radioactive isotopes.

What was the worst nuclear accident? What happened?

The worst nuclear accident happened in 1986 at the Chernobyl nuclear power plant in Ukraine and what happened was that unit 4 led to a rupture in the reactor and it led to a fire that lasted 10 days.

What happened at Fukushima?

In Fukushima a tsunami turned off the power supply and cooling supply to three nuclear power reactors causing a nuclear accident.

What are the harmful effects of thermal pollution to ecosystems? (Hint: Range of tolerance and dissolved oxygen)

Some harmful effect of thermal pollution on ecosystems is the loss of biodiversity.

Where is nuclear waste currently stored?

Nuclear waste is currently stored underground inside the nuclear power plant

What are the environmental benefits of nuclear power?

The environmental benefits of nuclear power plants does not emit no fine particles, nitrogen dioxide, sulfur dioxide nitrates or phosphates into the atmosphere

Why can’t nuclear power replace fossil fuels in the long term?

Nuclear power can’t replace fossil fuels in the long term because of operational risks and the associated safety concerns, uranium mining risks, financial and regulatory risks, unresolved waste management issues, nuclear weapons proliferation concerns, and adverse public opinion

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6.7 Describe the use and methods of biomass energy in power generation and the impact they have on the environment

Know:

Burning biomass produces heat for energy at a relatively low cost, but it also produces carbon dioxide, carbon monoxide, nitrogen oxides, particulates, and VOC’s. The overharvesting of trees for fuel also causes deforestation.
Ethanol can be used as a substitute for gasoline. Burning ethanol does not introduce additional carbon into the atmosphere via combustion, but the energy return on energy investment for ethanol is low.

More to know and understand:

🡪Biomass is the most common renewable energy source.

In unit 7 you will learn about specific air pollutants including particulate matter that is emitted from burning biomass. How do you think you could reduce particulate matter in a home?

Vacuum carpets and furniture every week, or more often. Dust often with a damp cloth. Dampening the cloth helps keep settled dust from going back into the air

Why is biomass used instead of fossil fuels for heating and cooking in developing countries?

Biomass is often used instead of fossil fuels for heating and cooking in developing countries because it is readily available, relatively cheap, and considered a renewable resource meaning it can be replenished through plant growth, unlike fossil fuels which take millions of years to form

What are some drawbacks to ethanol?

The production of ethanol requires large amounts of water and energy, which can contribute to water and air pollution.

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6.8 Describe the use and methods of solar energy in power generation and the impact they have on the environment

Photovoltaic Cells Active Solar Passive Solar

Diagram Credits: US Department of Energy

Know:

Photovoltaic (PV) solar cells capture light energy from the sun and transform it directly into electrical energy. Their use is limited by the availability of sunlight.
Active solar energy systems use solar energy to heat a liquid through mechanical and electric equipment to collect and store the energy captured from the sun.
Passive solar energy systems absorb heat directly from the sun without the use of mechanical and electric equipment, and energy cannot be collected or stored.
Solar energy systems have low environmental impact and produce clean energy, but they can be expensive. Large solar energy farms may negatively impact desert ecosystems.

More to know and understand:

🡪 Know how solar energy is captured and used from your energy diagram packet.

How do PV cells work? What are they made from?

PV cells work by converting sunlight directly into electricity through the PV effects. PV cells are primarily made from silicon, either from monocrystalline or polycrystalline and may include cadmium

What are some examples of active solar?

PV systems
Solar water heaters
Concentrated solar power (CSP) systems

What are some home design features of passive solar?

South facing windows which maximizes sunlight exposure.
Using Concrete and brick which absorbs and stores heat.
Insulation to retain heat in the winter and cool air in the summer.

What are drawbacks to solar power?

High Installation costs
The batteries used to store the power can be very expensive.
Requires large space for panels to generate significant amounts of power.

In the northern hemisphere, which direction should PV cells be faced?zq

PV cells should be faced south to maximize exposure to sunlight throughout the day.

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6.9 Describe the use and methods of hydroelectric energy in power generation and the impact they have on the environment

Know:

Hydroelectric power can be generated in several ways. Dams built across rivers collect water in reservoirs. The moving water can be used to spin a turbine. Turbines can also be placed in small rivers, where the following water spins the turbine.
Tidal energy uses the energy produced by tidal flows to turn a turbine.
Hydroelectric power does not generate air pollution or waste, but construction of the power plants can be expensive, and there may be a loss of or change in habitats following the construction of dams.

More to know and understand:

🡪After dams are built and paid off, hydroelectric (hydropower) is the cheapest MW to generate. Water behind a dam is potential energy and water flowing through a dam is kinetic.

Know how hydroelectric dams/power plants operate from your energy diagram packet

What are the benefits of hydroelectric dams?

Some of the benefits are providing flood control, irrigation support, and clean drinking water.

What are drawbacks to hydroelectric dams?

Significant environmental impacts like flooding large areas of land, disrupting aquatic ecosystems, and altering water flow, high construction costs

How do we solve the problem of blocked fish migration?

We open rivers and streams for fish by completely removing barriers. This can mean removing them with heavy equipment like bulldozers and excavators, or even blasting them away with dynamite.

What are the benefits and drawbacks to tidal power?

Although tidal power is considered a green energy source and doesn't emit any harmful gasses, the construction of tidal energy systems can have a substantial impact on surrounding ecosystems, like ocean habitats.

Where is the world’s largest hydroelectric dam?

Three Gorges Dam, China is the world's largest hydroelectric facility.

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6.10 Describe the use and methods of geothermal energy in power generation and the impact they have on the environment

Know:

Geothermal energy is obtained by using the heat stored in the Earth’s interior to heat up water, which is brought back to the surface as steam. The steam is used to drive an electric generator.
The cost of accessing geothermal energy can be prohibitively expensive, as it is not easily accessible in many parts of the world. In addition, can release hydrogen sulfide.

More to know and understand:

🡪 Geothermal energy can be utilized where magma is close to the crust. This does not occur everywhere on the planet which is a limitation for this energy source.

🡪 Know how geothermal energy power plants operate from your energy diagram packet.

Which country has the highest rate of geothermal? Why?

Iceland uses the most geothermal energy because it has lots of volcanoes, making it easy to get to the earth's heat

What are some drawbacks to geothermal?

Geothermal energy can be only be used in some place and can sometimes release gas or cause tiny earthquakes it's also expensive

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6.11 Describe the use and methods of hydrogen fuel cells in power generation and the impact they have on the environment.

Know:

Hydrogen fuel cells are an alternative to non-renewable fuel sources. They use hydrogen as a fuel, combining the hydrogen and oxygen in the air to form water and release energy (electricity) in the process. Water is the product (emission) of a fuel cell.
Hydrogen fuel cells have low environmental impact and produce no carbon dioxide when the hydrogen is produced from water. However, the technology is expensive, and energy is still needed to create the hydrogen gas used in the fuel cell.

More to know and understand:

🡪 Algae is being experimented with to create hydrogen.

🡪 Know how hydrogen fuel cells work from your energy diagram packet.

How do fuel cells work? (Mention cathodes and anodes)

Hydrogen fuel cells create electricity by joining the hydrogen and oxygen atoms. When hydrogen gas enters the fuel cells at anodes, hydrogens separate into protons and electrons. While electrons go through a circuit to make electricity. On the other hand, protons move to the cathode to combine with oxygen to form water.

What are the byproducts?

I would think the only byproduct of this is water. As the hydrogen fuel cells are very clean so they don’t release things like carbon dioxide or any other harmful substances.

What is the primary way we create hydrogen for fuel cells?

Hydrogen is produced by the process called Steam Methane Reforming. Where the hydrogen from natural gas is extracted but it releases carbon dioxide. Another cleaner method is called electrolysis where they split the water into hydrogen and oxygen that doesn’t produce any CO2.

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6.12 Describe the use and methods of wind energy in power generation and the impact they have on the environment.

Know:

Wind turbines use the kinetic energy of moving air to spin a turbine, which in turn converts the mechanical energy of the turbine into electrical energy (electricity).
Wind energy is a renewable, clean (releases no air pollutants) source of energy. However, birds and bats may be killed if they fly into the spinning turbine blades.

More to know and understand:

🡪 Know how windmills operate from your energy diagram packet.

What are the parts of a windmill? How does it generate electricity?

The parts of a windmill are the foundation, the tower, the rotor and hub (including three blades), the nacelle, and the generator. The turbines spin a generator which creates electricity, it is then sent to a transformer to be increased in voltage and transmitted through long distances.

What is the difference between a vertical and horizontal wind turbine?

A horizontal wind turbine is the usual one where the blades spin perpendicular to the wind direction to generate electricity while vertical turbines work in any direction and fit in small spaces.

Why are offshore wind farms more efficient?

Offshore wind farms are better than onshore farms because the wind is usually stronger and more consistent over the ocean.Offshore turbines can be larger and produce more energy.

What is NIMBY?

When people agree with building renewable energy projects but don't want them near their own homes.

How can we minimize impacts to birds and bats?

We can create turbine designs that lower the chance of birds and bats colliding with them like using larger blades that spin more slowly or adding features that make it more visible.

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6.12 Describe methods for conserving energy

Know:

Some of the methods for conserving energy around a home include adjusting the thermostat to reduce the use of heat/AC, conserving water, use of energy-efficient appliances, and conservation landscaping.
Methods of conserving energy on a large scale include improving fuel economy for vehicles, using BEF’s (battery electric vehicles) and hybrid vehicles, using public transportation, and implementing green building design features.

More to know and understand:

Why aren’t PV cells considered energy conservation?

PV cells are like solar panels. They make electricity from sunlight, but they don't help save energy. Energy conservation means using less energy, while PV cells just provide a different way to produce it.

What are CAFÉ standards? What are CAFE standards? Why are they helpful?

CAFE standards are rules that make car companies build vehicles that use less gas. This helps save fuel, reduce pollution, and lower costs for drivers by making cars more efficient.

What are subsidies?

Subsidies are money or support the government gives to businesses or people to help lower costs or encourage certain activities.

What are tax breaks?

Tax break is when the government lets you pay less in taxes, either by giving you a discount or a refund.

What are some features of green building design that help with energy conservation?

Some features are

Saving energy - LED lights
Using less water - collecting rainwater
Smart technology - lights that turn off by themselves to save energy.

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Math:

Percent Change

Ending amount - starting amount X 100
Starting amount

Scientific Notation
Metric Conversions

Percentages

Dimensional analysis

Watts and hours combine in energy math. Usually, we combine kW and h to get kWh. Your electricity bill is in kWh.

Example: A TV uses 200 watts and runs for 6 hours. This is 1200wh OR 1.2kWh.

We also use Therms (for natural gas) or Joules or BTU (for total energy use), but you do not need to memorize any special conversions for these units. They may be givens in the problem.

Half Life: Know how to sketch out and solve:

Text Analysis

Know how to find the author’s claims, evidence, perspective, and assumptions.

Experimental Design Terms

Independent variable

Dependent variable

Constants

Control

Experimental group: The group that receives the treatment or intervention being tested.
Control group: The group that does not receive the treatment and serves as a baseline for comparison.

Note