Energy SourcesChapter 9

Using Energy

Where does our energy come from?

How do we obtain our energy?

What types of energy are available?

What is Efficiency?Efficiency is the amount of work put in versus the amount of work gotten out.

Efficiency = output work (J)/input work (J) x 100

Non-Renewable Resources

•Include petroleum, natural gas, coal, and nuclear power.

•They cannot be replaced by natural processes at the rate which they are used.

What are Fossil Fuels?

Petroleum•Is a flammable liquid formed from decayed

ancient organisms.•It is made up of hydrocarbons.•Is used to make gasoline, heating oil, and

asphalt.•Is used to make plastics and synthetic

fibers.

What’s in a barrel of petroleum?

How Petroleum is Formed.

300-400 Million Years Ago

50-100 Million Years Ago

Today

Natural Gas•Is formed through the same process as petroleum.

•Mostly made up of methane, CH4.•Also contains butane and propane.•Is used to provide energy for cooking, heating, and manufacturing.

•Contains more energy per kilogram and burns more cleanly than other fossil fuels.

Coal•Is a solid fossil fuel that is mined

underground.•25% of all energy used in the United

States comes from coal.•90% of all coal used in the United States

is used in power plants to generate electricity.

•20-40 times more coal than petroleum.•It is the most inefficient and polluting of

the fossil fuels. It contains sulfur and nitrogen compounds.

How Coal is Formed

300 million years ago plants died and formed peat which is an accumulation of partially decayed vegetable matter.

The layer of peat was covered with a layer of sediment. The peat is compressed and forms lignite which is 25%-35% carbon. It accounts for 7% of the coal mined in the United States.

The lignite is compressed with high heat and pressure to form bituminous coal which is 45-86% carbon. It accounts for over half of the coal production in the United States.

The bituminous coal is further compressed to anthracite which is 86-97% carbon. It accounts for .5% of the coal mined in the United States.

Using Fossil Fuels to Generate Electricity

Chemical to Thermal 60% efficient

Water to steam 90% efficient

Overall 35% EfficientTurbine spinning the generator 95% efficient

Transmission through power lines 90% efficient

Steam turning the turbine 75% efficient

Costs of Using Fossil Fuels•Burning Fossil Fuels gives off smoke that

contains particulates and CO2.•Particulates can cause breathing problems.•CO2 contributes to the warming of the Earth.•Coal is the most abundant but is of the

lowest quality. Sulfur compounds in coal can cause acid rain.

•Fossil Fuels are a NON-RENEWABLE resource.

Why are Fossil Fuels non-renewable?

Nuclear Power•Is a non-renewable resource•Uses nuclear reactors to generate power

•Produces 8% of all energy consumed in the United States.

•Generates nuclear waste

Nuclear Reactors•Use nuclear fuel, usually Uranium-235

•Contain fuel rods, control rods, and cooling systems.

•Uses the energy of controlled nuclear reactions to generate heat

•Works through a process called fission

Fission

Generating Electricity with Nuclear Power

Renewable Resources•Includes solar, geothermal, wind,

hydroelectric, and alternative fuels.•Can be replaced by natural processes or

use natural processes.

Solar Power

•Can use photovoltaic cells to convert sunlight into energy

•Photovoltaic cells are made up of two layers of semiconducters

•It is 7-11 % efficient•Solar Power is more expensive than using

fossil fuels•Solar Power Plants concentrate the suns

rays to boil water and generate electricity.

Geothermal Power

•Uses the heat of the Earth to generate electricity

•Has an efficiency of 16%•Low to no pollution•Can only be used where magma is close to

the surface

Wind Power

•Uses wind to turn turbines and generate electricity

•Causes no pollution•They are 20% efficient•There are few places where wind blows

consistently with enough power to turn windmills

Hydroelectric Power

•Hydroelectricity uses the power of moving water to generate electricity

•Uses a dam to convert potential energy to kinetic energy

•Produces 8% of the electrical energy used in the United States

•It is 60% efficient since it does not use heat exchange

•Disturb natural ecosystems

Alternative Fuels

•Ethanol - can be made from corn or sugarcane

•Biodiesal – can be made from waste grease

•Hydrogen fuel cells•Biomass – renewable organic matter used

to obtain energy•Biomass is one of the oldest forms of

power and includes wood, sugar cane fibers, rice hulls, and manure

Energy Consumption

Where does the Energy Come From?

From Radioactive Decay•Geothermal•Nuclear Power

From the Sun•Fossil Fuels•Solar Power•Hydroelectric•Ethanol•Wind Power•Biomass

Geothermal

Nuclear Power

Biomass Ethanol

Hydroelectric

Wind Power Solar Power

Fossil Fuels