Lies, damn lies, and energy statistics

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Here is a simple and incredibly effective way to make it seem that a power plant will generate much more electricity than it actually will: talk purely about the amount of electricity it will supply to homes.

It’s a simple trick. It goes something like this: “Nuclear power plant to provide enough electricity for 5 million homes”; “Wind farms provide enough electricity for all of Scotland’s houses”. I’m sure you’ve seen it.

It’s an old fashioned PR trick. Most people do not know that around one third of Britain’s electricity is consumed by houses. What, then, are they to make of “millions of houses” as a unit of measure?

I consider myself well informed about these issues, and half capable of counting. But what am I to make of “millions of houses” as a unit of measure?

Consider this statement “Nuclear power plant to provide electricity for six million homes“, from a press release by the UK government about Hinkley C.

Six million sounds big and impressive. And that’s all it is: big and impressive. How is the average person supposed to figure out how big and how impressive it really is?

OK, so they start by thinking about houses. How many houses are there in Britain? Well, they aren’t likely to have the number memorized. But perhaps mental arithmetic can get them close.

So, there are around 60 million people in Britain. (I’m assuming most people know this, but I’m guessing many don’t.) Now, it’s probably well known that the average woman has around 2 babies. There was a even a BBC sitcom in the 1990s, whose title used the statistic (2.4 then, but lower now). So, Britain is made up (on average) of houses with a man and a woman and two children. There must be 15 million houses or so. Ah, hold on. Children go off to university; grandparents live alone. So, the real number must be a bit higher.

In fact, the real number is 26.4 million, according to official estimates; and I’m guessing that most people would guess anything between 10 and 40 million as the figure.

OK, now we are getting somewhere. 6 million houses out of 26.4 million can be powered by this nuclear power plant.

Ah, so it can provide electricity for 22.7% of houses.

But hold on! How much of Britain’s electricity is consumed by houses?

You can be pretty sure the average person doesn’t know this piece of information. I do, or at least I think I do. It’s roughly 33%. In fact, it’s roughly 33% for most developed economies. It’s a useful rule of thumb for people who do mental arithmetic about energy, but pretty useless to anyone else.

So, in the end, this nuclear power plant will generate roughly 7.5% of Britain’s electricity.

Now, why didn’t the British government say so when it made an announcement about it?

The answer, of course, is obvious. Press releases are designed to puff things up. It is the job of journalists to see through such things, and not re-report numbers designed to give false impressions. But almost every news story about a new power plant, wind farm, and so on, always uses the puff figures given in a press release. No effort is made to convert them into numbers that will really inform readers.

Tidal lagoons: an exercise in PR

Here is one final example. The Tidal Lagoon planned in Swansea Bay. Now, I’m rather skeptical of this project, as I explained here.

The project’s PR is perhaps as admirable as its economics and desirability are questionable.

Their press releases have used language in the most cunning of manner. Here is how it goes: “Tidal lagoons can provide 10% of Britain’s domestic electricity demand”.

Did you notice what they did there?


Well, neither did a lot of journalists.

The word “domestic” is key here. Domestic does not British, i.e. how much consume in Britain. Instead it means how much we consume in houses. So, of 10% of electricity demand, they really mean around 3%. Sound less impressive?

Yet, here is a list of media outlets that misreported the figure: the BBC, Guardian (they got it doubly wrong, replacing electricity with energy), Sky (in this case it was someone from the lagoon company who claimed it was 10% of energy, not electricity), CarbonBrief and I could go on.

CarbonBrief’s mistakes are particularly delightful. Tidal Lagoon’s apparently will generate 10% of Britain’s electricity. In turn this will be 3 times as much as Hinkley C nuclear power plant. Hinkley C being the nuclear power plant I discussed above. 7 times 3 equals 10.

But these kinds of errors are commonplace. Think of those media reports that tell you Germany gets half of its energy from solar panels. And then think of those official EU statistics which tell you the true figure is just above one percent.

Numbers matter. They should not be used to exaggerate, downplay or impress, but to inform.


CarbonBrief, to their credit, have since corrected the piece I link to above.


4 thoughts on “Lies, damn lies, and energy statistics

    Arthur said:
    March 30, 2015 at 1:18 am

    Yes I remember this in SEWTHA – thanks for updating the examples…


    Lauri Muranen said:
    March 30, 2015 at 7:51 pm

    You make a fair point but I think you are overly cynical about the motives of the PR-people. I would imagine using MWhs and TWhs would be equally confusing for the average person and one thing that people can relate these figures to is their own consumption at home. The people giving these figure should give a context though, or it can be rather misleading as you point out. And the examples are hilarious.

    I once heard the following definition for expertise: the more of an expert you are, it becomes increasingly painful to read articles about your area of expertise.


    Dan Olner (@DanOlner) said:
    April 16, 2015 at 12:08 pm

    David McKay’s take on defining the “home”. From part IV of sustainable energy without the hot air.


    […] Describing new power plants as powering X thousand/million homes is misleading at best and sometimes purposefully deceptive. […]


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