1. Chapter 8: Energy Sources and the Environment
Section 1: Fossil Fuels
Section 2: Nuclear Energy
Section 3: Renewable Energy Sources
Section 4: Environmental Impacts

2. Fossil Fuels Fossil Fuels Nonrenewable energy source
Formed from the decayed remains of ancient plants and animals
Burned to supply energy and generate electricity
Includes oil (petroleum), natural gas, and coal
Composed primarily of molecules of carbon, hydrogen, and oxygen (example: ethanol – C2H5OH)
Other elements are found in fossil fuels including sulfur (primarily in coal)
Fossil fuel consumption:
Total U.S. energy consumption (2008)
1.054 x 1020 J
83.4% from fossil fuels
8.748 x 1019 J
37.1% of total from petroleum
23.8% of total from natural gas
22.5% of total from coal
The U.S. consumes 20% of the world’s production of petroleum annually, is only 5% of the world’s population

3. Fossil Fuels Consequences of burning fossil fuels
Fossils fuels are composed primarily of carbon, hydrogen, and oxygen
The fuels are burned to produce useable energy
The reactions:
Gasoline: 𝐶 2 𝐻 6 𝑂𝐻+ 𝑂 2 + 𝑁 2 → 𝐶𝑂 2 + 𝐻 2 𝑂+ 𝑁𝑂 2
Coal: 𝐶𝐻+𝑆+ 𝑂 2 + 𝑁 2 → 𝐶𝑂 2 + 𝐻 2 𝑂+𝑆𝑂+𝑁 𝑂 2
Nat. Gas: 𝐶 3 𝐻 8 + 𝑂 2 + 𝑁 2 → 𝐶𝑂 2 + 𝐻 2 𝑂+ 𝑁𝑂 2 Notes: 1) Oxygen and Nitrogen are the two most abundant gases in the atmosphere 2) Coal is a hydrocarbon but typically occurs as a mixture with other, inorganic, substances
Greenhouse Effect
Allows energy from the Sun to enter Earth’s atmosphere, but heat given off by Earth is reflected back to Earth (acts like an insulator)
CO2 and H2O are greenhouse gases
Result: Since 1861 the average global surface temperature has increased by 0.33oC. Scientists project that in 100 years the average surface temperature could increase by 0.88oC to 3.5oC.
Result: 1) evaporation will increase
2) average global precipitation will increase
3) soil moisture will decrease
4) sea level could rise  20 feet

4. Fossil Fuels
Acid Rain
When coal is burned oxides of sulfur and nitrogen are released into the atmosphere
These oxides react with water vapor to form sulfuric and nitric acids: 𝑆𝑂 2 + 𝑁𝑂 2 + 𝐻 2 𝑂→ 𝐻 2 𝑆𝑂 4 + 𝐻𝑁𝑂 3
These acids fall as rain and result in acidic lakes, dying forests, and corrosion of metal structures
In 2008: (from utilities only):
5,461 million tons of CO2
2 million tons of NO2
5 million tons of SO2
Were released (U.S. only)

5. Alternatives to Fossil Fuels
Nuclear Energy:
Nuclear reactors – convert nuclear energy into heat. The heat from the nuclear reaction is used to boil water, turning it into steam. The steam is used to spin a generator turbine.
Solar Energy:
Energy from the sun
A renewable resource. It travels through space as sunlight and provides the earth with both light and heat.
Solar energy drives the winds, is responsible for the water cycle, and provides the energy necessary for plant growth.
Solar Heating
Passive solar heating – heat generating as a result of the simple absorption of solar energy.
No mechanical devices are used to transfer heat from one place to another.
Active solar heating – Uses mechanical devices to move heat form one place to another.
Most systems include solar collectors that gather sunlight and convert it into heat.
A heat exchanger is necessary to transfer the heat from water to the air in the rooms.

6. Alternatives to Fossil Fuels
Hydroelectric Energy:
Electricity is generated when the water held back by the dam flows through turbines.
Wind Energy:
Wind turbines – convert the energy of the wind into electricity
Wind farms are collections of wind turbines
Electricity generated by the turbines can be used directly or sold to a power company.
Geothermal Energy:
Heat that has its source within the earth
The heat is contained in magma which is melted rock
As the magma rises to within 4 to 6 kilometers of earth’s surface hot spots are formed
Alternative Fuels
Hydrogen fuel cells behave like batteries. They combine hydrogen with oxygen from the air to generate electrical energy, water, and heat.
Problems: obtaining hydrogen uses more energy than it creates, the cells are made of platinum (very expensive), and there is no infrastructure to support the use.
Biomass – renewable organic matter, such as wood, soy, corn, sugarcane fibers, rice hulls, and animal manure.
When burned biomass fuels convert chemical potential energy to thermal energy