Unit 9 - Energy Sources

Primary Energy Sources

 * Are sources that exists in nature.
 * E.g. Coal, Nuclear, Wind, Oil, etc
 * Oil produces the most energy in the world

Secondary Energy Sources

 * Are energy generated from primary energy sources.
 * Most commonly electricity

Renewable Energy Sources

 * Are sources that are replenished faster than consumed.
 * E.g. Bio fuel, wave, hydro, wind.

Non-Renewable Energy Sources

 * Are sources that are consumed faster than replenished.
 * E.g. Coal, Nuclear, Oil

Sustainable Energy Sources

 * Are sources that can be used indefinitely without serious/permanent harm to the environment.
 * E.g. Wind, Solar, Tidal

Sankey Diagrams

 * Are diagrams used to show the efficiency of a system and the degraded energy from production.

Image Example: ☀http://www.bbc.co.uk/staticarchive/3c6f516fb35a7c45f2f1738970ae40b82c445f62.gif

Energy Density (J/m3)

 * is the amount of energy stored per cubic metre of a given fuel.

Specific Energy (J/kg)

 * is the amount of energy stored per kilogram of a given fuel.

Fossil Fuel Power Plants

 * 1) If it is coal, then it must be ground into power for use
 * 2) Fuel is burned in the boiler,  which heats the water, and producing high pressured steam
 * 3) Steam passes through a turbine, which spins the generator, producing electricity
 * 4) Hot steam is then cooled back into water by using a nearby cooling source, usually a lake

Nuclear Power Plants
Advantages: No CO2, production is not environment dependent, large of amount of energy is produced
 * 1) Uranium is formed into pellets, and is used to undergo a controlled chain reaction that emits heat. A control rod and a moderator is used to ensure the reaction is controlled
 * 2) Pressurized water around the reactor vessel is heated, which transfers its heat to another system of steam pipes
 * 3) Steam is passed through a turbine, spinning the generator and producing electricity
 * 4) Steam is then condensed back into water using a cooling source such as a lake

Disadvantages: Large initial, reprocessing (waste managing) and regulation cost

Hydro-electric Power Plants

 * 1) A dam is built across a river to produce a reservoir
 * 2) Water is controlled by a flood-gate called a pen-stock
 * 3) After passing through the pen-stock, water spins a turbine, producing electricity.

Wind Energy
Kinetic energy of wind converted into electricity by turning the turbine blade

Equation: P = 0.5(A)(p)(v)3
 * A = 𝜋r2-> area of the turbine blade. r is length of the blade
 * p -> density of air
 * v -> speed of air

Solar Power

 * Obtains energy directly from the sun.
 * Works by having two cells - n-type (negative type) and p-type (positive type). Having them close together provides an electric current, thus generating electricity.
 * Solar Photovoltaics converts sunlight directly into electricity
 * Solar panels converts sunlight directly into thermal energy