What is Energy? Energy is the ability to do work

What is Energy?

• Energy is the ability to do work

Sources of Energy

• 1. Fossil Fuels• a. Coal• b. petroleum• c. Natural Gas• 2. Nuclear Energy• a. Fission• b. Fusion• 3. Wind• 4. Solar

More on Energy

• 5. Geothermal• 6. Hydroelectric• 7. Biomass

Fossil Fuels

Nonrenewable resources formed by the decay of plant and animal matter in the earth’s crust.

Coal

• 1. formed in the absence of oxygen from swamp plants which were buried for a long period of time under heavy layers of rock

Stages of Formation

• Characterized by the removal of impurities and moisture

Stage 1: Peat

• 1. 50-60% carbon• 2. dark brown spongy

substance that looks like rotted wood.

• 3. important energy source in Ireland and Russia

• 4. Can be cut, stacked.• 5. produces much

smoke but little heat

Stage II: Lignite: “Brown Coal”

• 1. 70% Carbon

• 2. lost most of its moisture, oxygen, and nitrogen

• 3. burns with a smoky flame, and produces little heat

Stage III: Bituminous “Soft Coal”

• 1. 80% Carbon• 2. more

compact and efficient

• 3. burns with a smoky flame.

Stage #4 Anthracite: “Hard Coal”

• 1. 90% carbon

• 2. burns hotter and longer with a blue, nearly smokeless flame.

Advantages of Coal:

• 1. plentiful supply

• 2. burns with great heat

Disadvantages of Coal

• 1. produces physical and chemical pollution:

• a. fly-ash

• b. acid rain

• c. co2

• d. smog

Dry Ash………..Acid Rain

II. Petroleum

• 1. Thick, black, liquid flammable hydrocarbon formed from the decay of marine organisms.

Oil• 1. mean “oil from rocks”

Oil Formation

Oil Formation

• 1. from dead one-celled organisms collected on the muddy ocean floor.

• 2. eventually sand and other materials cover these.

• 3. mud becomes shale• 4. hydrocarbon fluid from organisms

collected in the available space between rocks.

• 5. Pumped from oil fields

5. Pumped from wells drilled into oil fields

Oil can be separated into various compounds

• 1. propane• 2. butane• 3. ethane• 4. gasoline• 5. jet fuel• 6. Lubricants• 7. waxes• 8. asphalt

Oil is easy to transport

Other Advantages

• 1. easy to transport

• 2. cleaner than coal

• 3. produces greater heat

Disadvantages

• 1. limited supply

• 2. more expensive than coal

• 3. major chemical pollutant

Natural Gas

• 1. methane formed from the decay of marine organisms.

• 2. clean burning

• 3. less expensive than coal and oil

• 4. easily transported

• 5. limited supply

NUCLEAR ENERGY

2. Nuclear Energy

• A. Fission: Splitting of atomic nuclei resulting in the release of large amounts of energy

Uranium-235

• Chain reaction: neutron hits uranium nucleus, resulting in the release of great amounts of energy

• Krypton-94• Barium-140• 3 other neutrons• Nuclear power plants operate through

nuclear fission, which is the splitting of atoms to release energy. To accomplish this, radioactive uranium (U-235) is bombarded with free electrons

• Energy produced:

• heat from fission

• water is turned to steam

• steam turns turbines

• which run generators that produce

• electricity

Reactor

• 1. consists of 20 cm thick steel vessel which stands 10 m tall

• 2. uranium is in tubes in the lower part; top part contains control rods that move up and down which absorb neutrons, thus regulating (slowing or speeding the rate of reaction

• 3. contained within large, heavy concrete containment building

Advantages……Disadvantages

• 1. produces great amounts of energy with small amounts of material

• 1. safety hazards due to radioactivity

• 2. problem of waste storage 600-1000 years until it is not harmful

• 3. thermal pollution

Thermal Pollution

Fusion

Union of atomic nuclei to form heavier nuclei resulting in release

of large amounts of energy

• 1. four hydrogen nuclei join to form helium• 2. much like the sun

• Advantages:• 1. unlimited supply of hydrogen (ocean)• 2. non-air polluting

• Disadvantages:• 1. needs temperatures in millions of

degree to make the reaction occur

Wind Power

• Winds can be used to turn a turbine and generate electricity– Wind power plants “wind farms” consists– of many windmills. 1% of world’s electricity

- – fastest-growing energy source– free -- no pollution

• Wind Power - Using the wind to turn propellers connected to turbines. Wind power is considered renewable because the Sun and the Earth's rotation are always generating more winds. Wind power, like biomass and hydropower, is really another form of indirect solar power. The wind power resource of the United States, like its solar power resource, is huge. The dark blue areas in the map below show the areas where "class 6" winds exist. It is estimated that developing even a small fraction of these areas would power the US several times over, without creating adverse environmental or social impacts

Wind Power

Solar Energy

• Types

• 1. Solar Cell: made of silicon and small amounts of arsenic and boron and produces and electric current as sunlight strikes electrons loose from top layers

Solar Collector

• Sunlight heats water as it passes through black tubes located inside a has a clear plastic or glass top; hot water can be collected in a tank.

Power Tower

• Many mirrors are used to reflect sunlight to the top of the structure; here concentrated light heats water to produce steam which runs turbines and generates electricity

Passive Solar House

• Through a greenhouse-type structure on the side of a building, the sunlight strikes a storage mass (concrete, brick, or stone), which gives off radiant heat energy during the day and night which causes convection currents to carry warm air to the rest of the house.

Advantages

• 1. free supply of energy• 2. non-polluting

• Disadvantages:• 1. direct and constant use not available in

some places• 2. some methods are expensive• 3. storage problem during cloudy day

Geothermal Energy

Energy supplied from deposits of heat in the earth

Dry Steam

• Steam piped from wells to turbines which run generators to produce electricity.

Hot Water

• 1. piped directly to buildings for heat or to a plant where it is used to boil Freon (fluid with low boiling point of 30 degrees), whose vapor turns turbines which run generators to produce electricity

2. Geo pressurized Hot Water:this water which is under pressure due to dissolved

natural gas has not yet been developed as an energy source

Hot, Dry Rock

• This is the most common form of geothermal energy has not yet been developed as an energy source

• Advantages: free and clean source of energy

• Disadvantages:• Limited availability• Thermal pollution

Arguments• In order for the United States to

remain a world leader we must find sources of energy within our borders. We can not keep depending on other countries to provide us with energy. This means that sources such as geothermal energy must be researched in order to improve their productivity and affordability. Also geothermal energy is safe for the environment. It does not lead to global warming or the depletion of the ozone. And there is no waste material after the energy is used.

Advantages to Geothermal Energy

• Geothermal energy is a very good alternative to traditional forms of energy. It does not do harm to the atmosphere as burning materials such as coal or oil do. It helps to decrease the US dependency on foreign oil, and homes that use geothermal heating systems often pay much lower heating bills than those without.

• In fact the Soviets had discovered huge deposits of methane hydrate, methane gas molecules trapped inside cages of water ice in a form so concentrated that, when melted, the gas expands to 164 times its frozen volume.

• Gas hydrates are plentiful in permafrost; in the 1980s enormous quantities were found on Alaska's North Slope. Hydrates are even more plentiful under the sea. During deep-sea drilling in the 1970s, they were found to be the source of mysterious fizzing and bubbling-although an intact core sample of sea-bottom methane hydrate wasn't recovered until 1981

Hydroelectric Power

• 1. Produced by flowing water

• 2. Most widely used source of renewable energy

• 3. water stored behind dams falls through large pipes in the dam to a powerhouse where it moves turbines to run generators

• Advantages:

• a. power source is free

• b. self-renewing resource

• Disadvantages

• a. dams are expensive

• b. limited locations

• c. environmental concerns (lakes behind dams cover farmland, deposits of minerals, scenic areas, alters ecosystem.

Hydropower

• Hydropower - Channeling falling water to drive turbines (generators) to generate electricity. This is renewable because the Earth's hydrological cycle, which is driven by the Sun, continuously replenishes lakes and rivers through rain. Hydropower is an indirect form of solar power

Biomass

• Parts of plants or things made from plants that can be used for energy

• Examples: wood, leaves, stems, other plant parts, wood chips, trash, and animal wastes.

• Uses:

• 1. can be burned directly for heat energy

• 2. can be converted to fuels

• 3. biomass rotted in a closed container

• without air produces methane

• 4. Biomass containing sugar or starch, with the addition of yeast, produces alcohol; this alcohol can be mixed with gasoline to produce gasohol

• Advantages:

• 1. inexpensive power source in most cases.

• Disadvantages

• 1. could never be sole supply

• 2. practical aspects are being researched.