The Romans ground their corn by using water in the streams to turn their paddle wheels, like wind turns a windmill. Hydro-power stations improve on this method by using the power of moving water to turn turbines. At the Snowy Scheme, an operator in a hydro-power station just presses a button to open a valve and electricity can be supplied within two minutes. The water races down the pipes, turning the turbines which drive the generators producing electricity which is sent along transmission lines to your home. Then you can turn on a light, toast a piece of bread, use a computer, watch a video or do any of the other things which electricity lets you do.
Electricity demand varies throughout the day.
Peak hours of usage are in the morning, when you are getting ready for school or work, and when you come home at night. The seasons also influence your use of electricity. In winter, you use heaters, have a lot of hot meals and watch more television. In summer, you may use air conditioners and stock up your fridge with refreshing cold drinks and ice blocks. Because the Snowy Scheme can supply power almost instantly, it operates to meet this peak demand.