Electrical Energy

Electrical Charges Electrical Charges and Current

Like charges attract, unlike charges repel.

Coulmb’s Law

.

.2

21

r

qqkFelectric

Electric and Hydraulic Analogy

Current

Flow rate

Voltage

Elevation

Battery

Pump

Motor Water wheel

Series and Parallel Circuits Series

Same current passes through all devices

If one device fails, all fail Parallel

Currents add up Devices work independent of each other Fire Hazard

Units Charge C Current A Voltage V Resistance Energy kWh Power W, kW, MW, GW

PowerTable 1. Power Consumption For Several Household

Appliances*Appliance Power, W Appliance Power, W

Clock RadioTelevision (color)Freezer/RefrigeratorHair DryerWasher (clothes)Vacuum CleanerHome Computer

270 - 40065 - 200

600 - 10001200 - 1800

350 - 5001000 - 1400

100 - 400

Air ConditionerCoffee MakerIronDishwasherToasterMicrowave OvenDryer (clothes)Oven range

800 - 1000900 - 1200

1200 - 2400850 - 1400800 - 1400750 - 1100

1800 - 500010000 - 12000

Generation of electricity Thermal Powerplants Solar Photovoltaics Thermophotovoltaics Electrically Conductive Plastics Fuel Cells

Fuel Cells

Principle of Operation Electrolysis

H2O + electric current H2+1/2 O2 Fuel Cells

H2+1/2 O2 H2O +electric current

Generation

Storage Battery (chemical energy) Ultracapacitor (static energy) Flywheel (rotational energy)

Batteries Batteries are devices

that produce electric potentials Primary batteries Secondary batteries

Batteries are characterized by: Electrical potential Capacity

Transmission To reduce power loss we must

reduce current P=RI2

To reduce current we must transmit power at very high voltages (Since voltage is constant) P=V.I

Transmission Grid

Load and Capacity Base load Peak load Average load Capacity Factor Optimal Size

Load Duration