Alternative Energy Sources

How Electricity is generated…

• A force is needed to push the blades of a turbine• Turbine keeps a generator turning• Electromagnet produces electrical current

Traditional energy production (Fossil Fuels)

Combustion of Fossil Fuels

Hydrocarbon + O2 CO2 + H2O

Benzene – C6H6

(liquid)

Examples:• Methane (CH4) – small – Gas at room temp.

• Benzene (C6H6) – medium - Liquid• Paraffin (CxHx) – large - Solid

Uranium Uranium Pellets

Fuel Rod Assemblies

NUCLEAR ENERGY

Nuclear Fission • Energy within the nucleus of an atom is more than 1 million times stronger than the chemical bonds between atoms.• FUEL = URANIUM (nonrenewable metal)• Uranium atoms are bombarded with neutrons that cause the nucleus to split open and energy is released.

How Electricity is Produced from Conventional Nuclear Fission

Nuclear Energy Advantages

1. Energy is very concentrated in the Uranium (one pellet = 1780 lbs of coal = 149 gallons of oil!)

2. Non-polluting – only steam, not smoke

Disadvantages

1. Disposal of hazardous waste

2. Can be dangerous – meltdown or weapons

Low-Level Radioactive waste

High-Level Radioactive waste

Storage Options - Temporary/On-Site

Storing Spent Fuel in wet and dry storage

Temporary storage includes above-ground storage casks

Solar EnergyPassive Solar Heating – uses Sun’s solar energy to heat something directly

Active Solar Heating – Energy from the Sun is gathered by collectors and used to heat water or heat a building.

Photovoltaic Cells – Energy from the Sun is gathered by collectors and used to heat water or heat a building.

Solar Power Tower – Heliostats (mirrors) focus sun’s light on a central receiving tower. •A liquid is heated inside of a pipe.

• Hot pipe comes in contact with water & makes steam

Solar Energy

Advantages

1. “Fuel” is free (the sun)

2. Provides endless heat & light

3. It’s non-polluting

Disadvantages

1. Expensive to install/build

2. Need battery back up for night & cloudy days

3. Land-intensive

Wind Farm – large array of wind turbines that collectively generate electricity - Sun & convection produce wind

Wind Energy

Advantages

1. “Fuel” is free (sun wind)

2. Meet 10-15% of U.S. energy needs

3. It’s non-polluting

Disadvantages

1. Land-intensive

2. Large & Noisy

3. Hazardous to birds (flyways)

4. Consistent wind is on shoreline & mountainsides

Hydroelectric Energy – Energy produced from moving water

Advantages

1. “Fuel” is free (sun water cycle)

2. Water storage

3. High energy storage

4. Non-polluting

Disadvantages

1. Sediments build up behind the dams

2. Reservoir floods land

3. Disrupts fish migration

4. Too much development to build new dams

Hydroelectric Energy

Geothermal Energy – Groundwater that has been heated by energy within Earth’s crust

Geothermal Heat-pump

Geothermal Energy

Advantages

1. “Fuel” is free (hot water)

2. There is an abundance of hot water underground

3. Non-polluting

Disadvantages

1. Steam in one location only lasts 10-15 years

2. Will not produce a high percentage of power

3. Overuse & reinjection may deplete hot water

Tidal Energy – Energy produced from rising & falling tidal currents

Tidal EnergyAdvantages

1. “Fuel” is free (moon tides)

2. The tides are a steady source of energy

3. It’s non-polluting

Disadvantages

1. Limited use (area must have > 8 ft tidal range)

2. Block boat traffic

3. Hazardous to marine organisms

4. Corrosion in salt water