special feature
Switching on the kettle
Exploring electricity
Imagine a world without electricity ... no television, no computers, no traffic signals, no street lights.
Without our command of electricity, the world would be a very different place.
And to run our world, we need a continuous supply of electricity — lots of electricity. And since large quantities can't be stored, it has to be generated on demand.
The basic activities of electrical supply are straightforward ... generation, transmission, distribution. For public supply, the scale is huge and there are choices to be made, choices that affect the environment and the physical landscape.
But before we delve into the big questions, let's take a moment to look at just how
close to home this topic is .....
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What happens when I switch on the kettle?
introduction |  the command of electricity |  Faraday's work ...  biography of Faraday >
switching the kettle on |  supplying electricity |  an electrical conversation
history of public supply |  electrical timeline  |  definitions

We do it without thinking, don't we — "How about a cup of tea? Yes? I'll put the kettle on!" We just flick the switch. We don't really think about where the power is coming from or what's involved in maintaining a constant public supply.

What happens when I switch on the kettle?
technical information : John Biscoe  |  illustration : Paul Weston
So, how is electricity generated in the first place?
How is it distributed round the country and how are the voltages modified?
Want to know more .... supplying electricity >
Or you can eavesdrop on a conversation between the electrical engineer John Biscoe and engineering timelines. We quiz him on the ins and outs of electricity supply and and whether we have any choices .... an electrical conversion >
introduction |  the command of electricity |  Faraday's work ...  biography of Faraday >
switching the kettle on |  supplying electricity |  an electrical conversation
history of public supply |  electrical timeline  |  definitions

home  •  news  •  search  •  FAQs  •  references  •  about  •  sponsors + links
The household
power switch
is the tip of a very
big iceberg. In turning
it on, we tap into a vast
network stretching the
length and breadth of the country.

But the power can't just flow
unmodified directly into your kettle. Most household
appliances require low voltage power, typically 230V.
However, electricity is generated and transmitted at far higher
voltages, so high that the kettle would blow up
if adjustments weren't made.

Boiling a kettle ...
CARBON DIOXIDE EMISSIONS
Comparison of power station fuel sources

To boil 1.7 litres of water in a 3kW kettle ... for which it takes 4 minutes and 700kJ to raise the temperature from 10° to 100°

Coal .... 0.153 kgCO²
Oil .... 0.136 kgCO²
Gas .... 0.075 kgCO²
Nuclear .... 0.000 kgCO²
Hydro .... 0.000 kgCO²
Wind .... 0.000 kgCO²
Photovoltaic .... 0.000 kgCO²

Gas direct fire ... 0.042 kgCO²

These figure do not include CO² emissions relating to power station construction (embodied energy) or fuel sourcing and supply