2013: Advent Oil & Gas: Power and energy basics

by on December 1, 2013

It’s generally known that oil and gas are pretty big industries but it’s important to quantify exactly how big.  As this is the first article of Advent I’ll take the opportunity to run through some common units, and use them to get to grips with the scale of energy supply and demand.

The basic SI unit of energy is the joule, abbreviated as J.  If you use one joule per second, you are using one watt (W).  However, these are quite small units, so we’ll consider multiples of these using the standard system of prefixes:

  • One kilowatt (kW), 1000W, is roughly the power of an electric kettle.
  • One megawatt (MW),  1000000W, is roughly the power of a commuter train.
  • One gigawatt (GW), 1000000000W, is roughly the power of a large nuclear reactor.
  • One terawatt (TW), 1000000000000W, is roughly the power of a lightning strike.  (That’s one trillion watts, so twelve zeroes.)

To find energy, multiply the power by the time in seconds.  This is important when working out total consumption.  For instance, a typical lightning bolt, despite its very high power, will deliver an energy of just 30 megajoules (MJ) because it lasts a fraction of a millisecond; compare this with the 200MJ or more that an average car will use on a one-hour journey.

Quite often the power is instead multiplied by the time in hours, to get the energy units of watt-hours (Wh), kilowatt-hours, and so on: a kilowatt-hour is therefore equal to 3.6MJ, and is about how much energy you will use if you boil a kettle for an hour or run your car engine for just one minute.

With that in mind, let’s look at the scale of energy consumption in the UK.  We used a grand total of 2490TWh in 2012, which equates to an average power of 336GW.  A quick look up tells us that this is roughly the output of three hundred and thirty-six big nuclear reactors running all the time.  Oil and gas made up well over half of this total, including a quarter of our electricity generation (223TWh), the majority of our domestic heating and cooking (490TWh), and almost all of our transport (656TWh).

By now it should be clear that when we are talking about oil and gas we dealing with some quite large numbers.  Just to underline that, next time you’re in your car, consider that the power consumed by UK road traffic alone is equal to almost ninety nuclear reactors I hope that sounds like a lot, because it is!

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