When you walk into a dark room, the first thing you do is to hit the switch and put on the light, and when you  spend time outside the house in hot weather, as soon as you get indoors you reach out for something cold in the fridge. But have you ever stopped to think how this technology that has made life so convenient gets to your house? Well, for you to be able to use it in your home or office, the electricity has to go through a long process.  It can be generated from various power plants using materials like coal, natural gas, water and wind. Once it is produced, it then has to be transported through long distances. Before this is done, the current is lowered and the voltage increased in a process called “stepping up". All this happens inside transformers and then the high voltage electricity is transported through thick lines that can withstand the high voltage.

Source: wiring professionals