How is electricity distributed?
The short answer is that electricity is distributed by cables, however the actual process is a lot more involved than simply running power down a single line.
The first step in the distribution of electricity is creating the electricity itself. That happens in power plants, where electricity is generated by a variety of methods – in the UK the power mix is predominantly renewable sources such as solar, wind, or hydroelectric plants. In these plants, power is produced at between 2.3kV and 30kV.
Once the power has been generated, it is sent across the country via a network of high voltage, long-distance cables. As the electricity leaves the power plant, it runs through a transformer which increases the voltage up to between 115kV to 756kV. The increased voltage reduces the energy lost as the electricity travels long distances, making the transmission of power more efficient. The cables for high voltage transmission are usually overhead lines, with the choice of cable dependent on the environments it will pass through and how far apart the supports (pylons) are spaced.
The network (known in the UK as the ‘national grid’), connects at various points to substations. These substations will convert the electricity to progressively lower voltages ('stepping down') for transmission across shorter distances to towns and neighbourhoods. These cables are generally still bare overhead lines, though in some areas such as cities these cables can be buried underground, whether directly or in cable ducts.
The final substation sees a step down from 11kV Medium Voltage power to the low voltage power suitable for domestic properties and industrial buildings - three phase power at 400V and single phase power at 230V. This can then power outlets, lighting circuits, and all the systems that rely on electricity to operate.
It’s important to note that the electrical current being transmitted across the grid is AC - alternate current. Some industrial systems rely on DC power so convert it before use – arguably the last step in the power distribution process. The reverse process happens with solar panels which produce DC power and then have an inverter transform to AC power for distribution and use.
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