Science - Chapter 8

What are fossil fuels?

Nonrenewable carbon-based resources formed between 150-300 million years ago from remains of dead organisms

What are the types of fossil fuels?

Petroleum or oil, coal, natural gas

How is oil formed?

Partially decomposed ancient marine microorganisms sunk to ocean floor and over time, were buried under layers of sediment and rock.  

Made up of a mixture of hydrocarbons

How is oil extracted?

1) Seismic surveys are used to locate likely rock structures underground in which oil and gas might be found.

2) Shock waves are fired into the ground. These bounce off layers of rock and reveal any structural domes that might contain oil.

3) Once an oil or gas prospect has been identified, a hole is drilled to assess the potential oil

(The cost of drilling is very great.  On an offshore rig, it may cost $10,000 for each meter drilled. A company incurs vast losses for every “dry hole” drilled)

4) Once extracted, oil and gas must be sent to a refinery for processing

5) Pipelines transport most of the world’s oil from well to refinery

6) Massive Oil Tankers also play an important role in distribution

What is oil used for?

• Transportation Fuels (gasoline)

• Electrical generation

• Asphalt

• Plastic!

How is natural gas formed?

• Formed in the same way that oil forms

  • Due to density differences, natural gas is found trapped on top of petroleum deposits

• Composed of mostly methane, but could also contain butane or propane

How is natural gas extracted?

Natural gas is extracted by drilling wells into subsurface rock formations.

For conventional gas, a well is drilled into a porous rock formation, and the gas is released and brought to the surface. 

For "unconventional" or shale gas, which is trapped in low-permeability rock, a technique called hydraulic fracturing ("fracking") is used to fracture the rock and allow the gas to flow out. 

What is natural gas used for?

• Cooking

• Heating homes

• Manufacturing

How is coal formed?

1) Decomposing swamp plants buried under mud with no oxygen, these remains produced peat.

2) Peat = partially decayed vegetation

3) Over time, increased pressure & heat transformed this peat into the coal we use

How is coal extracted?

1) Exploration to locate coal deposits

2) Followed by surface or underground mining to extract the coal, which includes removing overburden, drilling, blasting, and loading

What is coal used for?

• Generate electricity

• Manufracture steel

• Produces cement

How coal is converted from chemical potential energy into electrical energy:

1) Coal is burned in a furnace- converted to thermal energy

2) Thermal energy heats water to make steam

3) Steam turns a turbine

4) Turbine blades spin an electric generator

5) Electrical current transmitted along power lines

Why use coal?

• Safer to ship, cheaper to extract, abundant in US

  • Wyoming, Appalachian 

Mountains hold majority of US coal

• Inexpensive

Cost of coal:

• More air pollution than any other fossil fuel

  • CO₂ released into the atmosphere -> global warming

• Extraction= lots of environmental damage

  • Many hazards associated with mining

Combustion Reactions:

Methane

Ethane

Propane

Butane

Octane

Methane: CH4 + O2 —> CO2 + H2O

Ethane: C2H6 + O2 —> CO2 + H2O

Propane: C3H8 + O2 —> CO2 + H2O

Butane: C4H10 + O2 —> CO2 + H2O

Octane: C8H18 + O2 —> CO2 + H2O

Pros and Cons of Fossil Fuels

Pros: 

• Fossil fuels are well developed

• Low-cost energy source

• Reliable energy source

Cons:

• Contributes to climate change

• Non-renewable source

• Fossil fuels are unsustainable

• Land degradation

• Accident-prone

• Human health impacts

Difference between renewable and nonrenewable resources

Renewable resources are naturally refilled over a short period, while non-renewable resources exist in a fixed amount and are consumed much faster than they can be produced

Differences between fission and fussion

Fission: 1 atom splits into 2 atoms

Fusion: 2 atoms comine into 1 atom

Components and functions of a nuclear reactor

A nuclear reactor contains components like the reactor core, which includes the fuel (uranium pellets in fuel rods), control rods (to regulate the reaction), moderator (to slow neutrons), and coolant (to remove heat)

Nuclear Fuel

Nuclear fuel is a material, like uranium, that can release energy through nuclear fission or fusion.

A substance is good for nuclear fuel if it has a high-energy density and contains isotopes that are either fissile (can be split) or fertile (can be converted into a fissile material), allowing for a sustainable energy reaction. 

Pros and Cons of Nuclear Energy

 

Pros	Cons
Does not produce air pollutants that burning fossil fuels does No release of CO2 Large amount of energy produced from small amount of uranium	Disposing of nuclear waste is difficult Uranium is not renewable Power plants expensive to build, takes 10+ years Radioactive material harmful to living organisms and the environment

Nuclear Waste

• Nuclear Waste- leftover radioactive material from fission reactions, must be disposed of 

• Half-Life- the amount of time it takes for half of a substance to decay and become non-radioactive

  • Low-level waste- short half life

  • High-level waste- long half life

• Most nuclear waste is stored in durable, stable containers and buried underground

How does solar energy generate electricity?

How a solar panel works A photon hits one of the silicone atoms  Knocks off an electron  The free electrons make their way to a metal conducting strip on the solar cell surface. The strip transports steady stream of electrons out of the cell, so that it can flow into the powergrid

Pros and Cons of Solar Energy

Pros: 

• Reduces electricity bills

• Low greenhouse gas emmisions

• Reduces carbon footprint

• Increases home value

• Improves air and water quality

• Conserves water

Cons:

• High cost

• Cannot be used during the night

How does hydroelecticity produce electricity?

1. Hydro electric power plants are built on rapids, waterfalls, or creates falling water by damming a river.

2. The moving water spins a turbine

3. The turbine is connected to a generator

4. The generator has electro magnets on the rotor which spins because of the turbine, within coils of copper wire.

5. This process creates a flow of electrons in the copper wires which can be turned into electricity.

Pros and Cons of hydroelectricity

Pros:

• Low greenhouse gas emmisions 

• Flood control

• Irrigation

• Reliable and flexible

Cons:

• Cost

• Building a dam ruins the environment

• Limited locations

How does tidal energy produce electricity?

1. Takes energy from the rise and fall of tides.

2. Caused by an earth's gravity and the gravitational interaction from the sun and the moon

3. It spins the turbines and generates electricity.

Pros and cons of tidal energy

Pros:

• No greenhouse gasses

• Predictable and reliable

• Provides a more consistent energy output than wind turbines and energy

Cons:

• It is also very slow

• Has bad environmental side effects

• Inexpensive

How does wind energy produce electicity?

As the wind blows, the propeller spins, the propeller is connected to a generator the greater the wind speed and the longer the wind blows. The greater amount of wind energy is converted to electrical energy.

Pros and cons of wind energy

Pros:

• renewable source

• does not pollute the air or water

Cons:

• wind is unpredictable

• can only be put in a few places.

How is geomthermal energy produced into electicity?

Heat from the earth’s crust is warming water that has seeped into underground reservoirs. When hot enough, the water breaks thrush as hot water or steam, where it is pushed into a pipe for a power plant. Here,it can spin turbines to get generators to generate electricity.

Pros and cons of geothermal energy

Pros:

• Low carbon dioxide emissions produced

• A small carbon footprint

• If there is gas being produced, it is usually diluted with water, and injected underground.

Cons: 

• The cost of building a geothermal plant

• Geothermal energy is limited to areas where volcanic activity is and where the magma is near the surface.

How does biomass produce electricity

Plant waste, wood, scraps sawdust, and crop waste can be collected from farms or manufactures. The waste is burned to heat water, the hot water creates steam. Then the pressure of the steam spins a turbine, the turbine powers a generator. Finally, the generator creates electricity.

Pros and cons of biomass:

Pros:

• Protects ecosystems

• Prevents greenhouse gas emissions

• Carbon-Neutral

Cons:

• Not entirely clean

• Can lead to deforestation

• Biomass plants require an abundance of space.

What is a natural greenhouse effect?

• Keeps our atmosphere livable- without it Earth would be near 0 degrees F!

• Sun’s energy is absorbed by Earth’s land and water

• Land and water give off energy in a different form- infrared radiation

• Greenhouse gases trap infrared radiation (heat) and keep our atmosphere warm

How are humans enhancing the greenhouse effect?

• Humans are adding to the amount of Greenhouse Gases in the atmosphere by burning Fossil Fuels

Types of greenhouse gasses

H₂O (Water vapor), CO₂ (Carbon dioxide), CH₄ (Methane), O₃ (Ozone), N₂O (Nitrous Oxide )

Definition of albedo and examples

• ability of a surface to reflect away solar radiation

• Light colored surfaces have a high albedo (snow, glaciers)

• Dark colored surfaces have a low albedo (oceans, pavement)

Connection of melting polar ice and earth’s overall albedo

Melting polar ice reduces Earth's overall albedo