l Kinetic energy

l Potential energy

l Thermal energy

l Chemical energy

l Nuclear energy

l Electrical and magnetic energy

 

 

l Fossil fuels (coal, oil, natural gas)

l Nuclear

l Solar

l Geothermal

l Hydro

l Wind…

 

 

l Contain carbon or hydrocarbons.

l Around 75% of the world energy consumption comes from fossil fuels.

l The resource is depleting very rapidly.

l Environmental Impact: Pollution; Acid rain; Global warming.

 

 

(1) Emission of sulfur dioxide and nitrogen oxides from burning of coal.

(2) Sulfur dioxide and nitrogen oxide gas combines with water and forms acid.

(3) Acid float up into the clouds.

(4) Come down as acid rain and cause damage.

 

 

Solar radiation penetrates the glass covering of an ordinary greenhouse rather efficiently, but the infrared radiation from inside the greenhouse does not go out.

 

 

(1) Higher sea levels, flooding of coastal areas and Salinity intrusion

(2) Increased droughts

(3) Increased incidence of storms

(4) Impact on food production

(5) Impact on natural ecosystems

 

 

AC (current) has zero-crossing point, and is relatively easier to die out as compared with dc (dc circuit breaker is very expensive!)

 

 

Power through a Resistor: Twice the frequency. Average power consumed is equal to RI². Current & Voltage occur simultaneously.

 

Power through a Capacitor: Twice the frequency. Average power consumed is equal to 0. Current lead Voltage. Average energy stored:

 

 

Power through a Inductor: Twice the frequency. Average power consumed is equal to 0. Current lag Voltage. Average energy stored:

 

 

 

9. S = VI* = P+jQ

On the transmit line, P proportional to Δθ, Q proportional to ΔV. So we could use Δθ to control real power, and use ΔV to control reactive power.

Capacitor “injects” reactive power into the network.

So capacitor can be used to control voltage and to reduce losses.

We have Q_c = -wCV²

 

10. In power system operation, the main concerns are reliability and economics (in that order).

For real-time operation, AGC (Automatic Generation Control) is used to instantaneously balance generation and load.

 

Economic Dispatch: To minimize the total cost of production of Electricity. The optimal point occurs when all generators have equal incremental cost

Unit commitment: To determine for a specific period of time which generators should put into use in order to save cost.

 

 

1 kcal = 1 Calorie

1 watt = 1 joule/sec

Watt-hour = 3600 joules