Generating Electricity

What Is Energy?

• Energy has many different forms. • When an object is able to change its

environment, we say the object has energy.• Energy is the ability to do a task, such as

moving an object.

Common Forms of EnergyForm of energy Examples

Chemical - Gasoline; food; fireworks

Thermal - Warmth from a fire

Sound - voices; music

Radiant (light) - sunlight; microwaves

Mechanical - wind; running water

Electrical - lighting; electricity for your home

Energy Transformations

• There are many ways to change or transform one form of energy into another form.– Your body and a car’s engine change chemical

energy into mechanical energy.– When you bang a drum, the mechanical energy is

changed into sound energy.– A wind turbine changes mechanical energy into

electrical energy.

Examples of Energy TransformationsExample Energy Transformations

Solar panel Light energy electrical energy

Fire Chemical energy thermal energy and light energy

Wind turbine Mechanical energy electrical energy

Car engine Chemical energy thermal energy mechanical energy

Light bulb Electrical energy thermal energy and light energy

Generating Electrical Energy

The Grid:• Most or the electrical energy we use comes to

us through the electrical energy distribution grid.

• The electrical energy distribution grid is a network that carries electricity from the energy generating station to the consumer.

Generators:• Most energy is distributed by the gird is

produced in electrical energy generating stations.

• These stations use generators.• A generator is a machine that converts

mechanical energy into electrical energy.

• The energy in the wind, flowing water, or stream can be converted into electrical energy.

• The movement is used to push blades of a fan-like device called a turbine.

• The turbine is connected to the wire coils inside a generator.

• When the turbine spins, the coils of a wire generate electrical energy as they spin at high speed near powerful magnets.

Measuring Electrical Energy

• All energy is measured in joules (J).• How quickly we use electrical energy can be

measured as the number of joules used per second.

• A joule per second is called a watt (W).• A 20 W bulb uses 20 J or energy per second.

• A joule is very small, so we often use a much larger unit, the kilowatt hour (kW h).∙

• A kilowatt is 1000 W.