Electricity. It powers every single modern piece of technology in our lives, from computers and mobile phones to the lights and appliances in our homes. It’s such a ubiquitous and well-developed utility, we completely take it for granted – yet so many of us have no idea how electricity actually works.
In light of our customer satisfaction ratings for electricity providers, we’ve decided to create a comprehensive guide in plain English to help you understand the most important form of energy in the world.
What is electricity?
In the context of power supply, electricity is simply the motion of electrons around a circuit from a negative terminal to a positive terminal. The positive terminal attracts the negatively charged electrons, and as they move from one atom to the next, they carry kinetic energy – energy which can be harnessed to do work in electronic devices.
An electric current moves at close to the speed of light, though individual electrons move fairly slowly between atoms. Some substances are better at conducting electricity than others – the most widely used material in wires is copper, due to its great conductivity and abundance in nature. Conductive materials are known as conductors, and non-conductive materials are known as insulators. Many polymers and plastics are good insulators, hence why you often see them used to coat wires.
How is electricity measured?
The most common measurement of an electric current is how much power it’s delivering to a device; the units of power are watts (W), where 1 watt is equal to 1 joule of energy per second. This is more commonly expressed in kilowatts (kW), where 1 kilowatt is 1000 watts.
Another common measurement is the total amount of energy being supplied (or used by an appliance), and for this the most common units used are Kilowatt hours (kWh). 1 kilowatt hour means the total energy provided at a rate of 1kW over the course of an hour, which is 3.6 megajoules. Engineers often need to measure the current (electrons per second) and voltage (energy per electron) of an electric current, but they’re not usually necessary in a domestic context.
How is electricity produced?
Electricity is simply a form of energy, which means that is can be generated from many different energy sources in nature. Electricity is always produced using a generator, which converts mechanical energy into electrical energy. A generator consists of a spinning magnet on a shaft, surrounded by wire (or spinning wire coils surrounded by a magnet); the shaft is connected to a turbine which is powered by whatever energy source is being harnessed. When the wires move relative to the magnet, it induces electrical current – a great animation of this can be found here.
There are a variety of energy sources in nature that we use today: power plants can burn coal or gas to create steam which spins turbines, windmills are spun by the wind and generate electricity directly, hydro plants use the energy of flowing water to drive turbines, solar panels use sunlight to generate electric current through the photovoltaic effect – there are a lot of ways to generate power.
How is electricity stored and transported?
Electricity is transported through the electricity grid – basically a collective term for the nationwide network of producers, transporters and retailers which provide electricity to homes and businesses. After being generated at a power station, electricity is converted to high voltage using a transformer before being transported long distances along power lines to residential areas – the reason for this is that increasing the voltage decreases the current, and doing so reduces the amount of heat loss due to electrical resistance.
Electricity output at power plants nationwide needs to be closely matched to demand to avoid waste energy or inadequate supply. To achieve this, the Australian Energy Market Operator operates the National Electricity Market to facilitate sales between producers and retailers, and to supply demand data to produce electricity as efficiently as possible.