Re: Where does electricity come from?

The electricity that you get when you plug something into a wall socket in 
your house has traveled several miles over wires to get there.  The 
electricity arrives in the form of 250 volts in England (125 volts in the 
US) alternating, meaning that the positive and negative side switch places 
50 times (60 in the US) every second.  This is different than the 
electricity that you get out of a battery, which is direct current.  The 
battery terminals are positive and negative, and the positive side stays 
positive all of the time.  Alternating current is easier to transport over 
long distances, and makes such things as appliance motors and clocks easy 
to design and build.

The electricity itself is generated at a central power plant somewhere near 
you.  The plant has a large machine called a generator that creates an 
electrical voltage as it is turned.  The power to turn it comes from either 
a steam or gas motor called a turbine.  All of the energy created by 
burning coal, gas, or other source is converted to electrical energy.  This 
electrical energy is then sent along wires to all of the homes and 
businesses in the area.

Many power plants exist in the world, and they stay connected by a power 
grid similar to the internet.  If one goes down for repairs, the others can 
help fill in the gap by running a little harder to make up the difference.