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## The price of power

No, this isn't going to be a rant about the blatant Tory corruption where his Covid startup fund sent nearly £2 million to firms linked to his not-lacking-for-money wife; or how his "solution" to the recent by-election defeats appears to be to propose tax cuts for top earners.

Instead... it's quite literally about the price of power, that invisible (but increasingly expensive) entity that wiggles out of the end of a wire.

I've seen various red top newspaper articles with some rather shady maths in them telling you how much electricity you're using. So I thought I'd have a crack at it...

Your electricity bill, and various adverts, will tell you about the price of electricity. It'll tell you it's a mere 15p per kilowatt hour, or somesuch.
While that is technically correct, that isn't the price you'll be paying. My electricity, for example, is a flat rate of €0.1868/kWh (five centimes more than last year!). That means my 216 units came to €40,35. But then one must add the service charge (€26,46) and the service taxes (€4,68) and then the VAT on all of that (20% = €8,11 and 5.5% = €1,71).
The final result? €81,31.

So the simplest way to get an idea of how much each unit of electricity is costing you is to take the price you paid and divide that by the number of units you used. This will be on your electricity bill somewhere. For me, it's 0.37643 (etc), so let's call it €0,38 per unit.

All of my prices are given in euros and centimes as I live in France. However it's just a name, all you need to do if you're British is swap in the appropriate values, then it's pounds and pennies for you.

### A cup of tea

If you're smart and only fill up the kettle as much as you need for a cup of tea (don't fill the kettle all the way up), then it ought to be done in about two minutes.
The average kettle is about 2kW, which means it'll consume two units in an hour. But heating in two minutes means you'll be able to make about thirty cups for an hour's worth of electricity. Divide that by two (as it is two kilowatt), gives us a value of fifteen. Take the price per unit and divide by fifteen...
And making yourself a cup of tea costs €0.025, so round this to three centimes per cup.
A sad irony is that with French tea prices, it's around €0,20 per tea bag! Which is why I buy proper Tetley in sacks of 1,100, which costs a much better €0,04 per bag.

...which reminds me, time to go put the kettle on. ☺

### Making a cake in a mini oven

This will take about half an hour in an electric oven, however the oven won't be on all the time. How long it will be on depends a lot on the design of the oven and how well insulated it is, suffice to say that "being on half the time" seems about right (especially if you have a mini-oven). This means we'll have the oven running for a total of fifteen minutes.
Now since most cakes have two layers, we should double this for the second layer. Half an hour of heating.
Now we should add in preheat time. It isn't unreasonable to need at least ten to fifteen minutes to get the oven up to working temperature.
Now we're up to 45 minutes. A mini oven typically has two heating elements. One at the top, one at the bottom, and they're both 1kW each and typically they both need to be on.
So... forty five minutes at 2kW. We'll work out 45 minutes at 1kW because that's just dividing the unit by four and multiplying by three (for three quarters of an hour), then double it for the other kilowatt.
Which means it'll cost €0,57 to bake a cake in a mini oven.

If you have a regular electric oven, the timings are typically the same except you can do both layers of the cake at the same time, so it's thirty minutes of 2kW heat. Which equals a kilowatt, or €0,38.

As for Sunday Roast... I've found everything from fifty minutes to five hours (!), so let's just make it easy and say it'll be about unit for every half hour of cooking.

### A jacket potato in a microwave

Mom's recipe was simple. Stab a potato a few times and pop it in the microwave for ten minutes. Turn it over, give it ten more minutes.

Now the problem here is that while your microwave will be rated something like 800W, that's talking about the output power - how much radio energy is being blasted into that poor spud.
The input power is going to be higher. The magnetron is not 100% efficient, so you'll be looking at maybe something in the range of 1.1kW in to get 800W out. Add to that the turntable and the light, and it'll typically add up to something like 1250W. Your microwave will have a rating plate on the back (or bottom) that will tell you its real power consumption.

This, we can calculate too. Divide the price of a unit by a thousand (so per watt), then multiply by the rating of the oven. This means it'll cost about €0,48 to run it for an hour. Since it was only twenty minutes, divide by three.
Which means making a baked jacket in the microwave will cost €0,16.

### A jacket potato in a halogen cooker

When I do it, it's an hour on one side and an hour on the other. It's much slower than a microwave because you're heating by convection, but on the other hand it produces a far superior result.
As halogen ovens tend to be horribly lacking in insulation (it's just a thick glass bowl), it isn't unusual to see that it'll be on for easily half the time. On the other hand, it's basically a fan and a bright floodlight (sort of). Which means your energy rating is going to be something in the order of 1300W.
Being rated a fraction more than the microwave, it'll cost €0,49 per hour to run. Two hours, of for half the time? Let's call it €0,50 for a jacket potato.

By way of comparison, doing the same in a regular oven will cost a fair bit more as that will be around 2000W plus preheat time. You'll notice I didn't bother to mention preheat as for a halogen oven it's something like four or five minutes, I just set it running from cold and factor that into the cooking time...which is basically "turn the knob as far as it'll go".

### Chicken nuggets in an air fryer

About seven minutes of preheat time, plus about eight minutes of cooking time. My air fryer seems to do things like nuggets and fish fingers in about half the time it says for oven cooking, though it's all rather experimental as cooking instructions on packets rarely mention air fryers.

An air fryer is a little ring heater rated about a kilowatt, and a fairly beefy motor to keep that fan turning. With the proximity of the heat source, plus the fan, it is convective heating with attitude.
Typically consuming around 1500W, it'll consume a unit and a half per hour (or €0,57), but being so damn quick it'll only cost you around €0,14 to make nicely crispy nuggets. Or chips. Whatever.

Note: While an air fryer has a temperature control, in my experience if you leave it set at 200°C (which is the temperature most things want to be cooked at), it probably won't click off...especially if you take the panier out a few times to shake the contents.

### Internet box

Also broadly counts for other similar rated things like printers on standby, mobile chargers, and so on.

Let's assume eight watts. Actual consumption varies wildly, and any markings on the device itself are liable to refer to the DC input consumption, not the AC consumption of the power brick.

Eight watts means you can run it for 125 hours for a unit of electricity. That's five-and-a-fifth days. There are 8,760 hours in a year (we'll ignore leap years for simplicity) which means 8750÷125 gives us 70 units. Which means keeping the internet running will cost you around €26,60 per year.

Now multiply this for all the stuff you leave plugged in.
Go on, unplug that inkjet printer if you aren't using it. It doesn't have a switch on the front, it has a little press button just like the "paper feed" one. Which means that the internal controller is always running in order to respond to it.

### Satellite TV

Because of the need to power the LNBs and some rather meaty computational stuff going on inside, your typical satellite TV receiver will be drawing something in the order of 20-25W.
If we assume 25W, that means 40h per unit, or 219 units per year. Which is €83,22 per year.

Note that in the case of receivers with integrated programme guide, putting the box into standby doesn't actually do much. The video output is blanked and the little LED turns red. However in order to keep the EPG up to date, deal with middle-of-the-night firmware updates and so on, the box is pretty much entirely active all the time. As long as you can tolerate the several minutes it takes the thing to start up and get programme updates, it would make much more sense to unplug it when it isn't in use. Here's a thought... if you use it for around six hours a day, that means there's eighteen hours when it isn't being used. Which means you're paying around €21 for watching satellite TV... and around €62 for nothing.

### Water heater

This is the second most frightful one.

Two hundred litres, from cold. You're looking at four or five hours. At a typical rating of 2.2kW.
Which means €0,84 per hour, or €3,36 to €4,20 to heat it. If you bath even once a week, then you're going to be looking at around €200 per year just for bathing.

Alternatives exist, such as on-demand showers, or simply boiling a kettle or two of water, putting it in a bowl, and washing like they did in the 18th century...

### Electric heating

For a two kilowatt space heater (bar heater, fan heater, whatever) the calculations are much the same as for the water heater.

However, rather than spending money to always heat a space, try heating it only when you need it. For other times, such as when you're in bed, an electric blanket will be much better as it'll heat you for a small amount of electricity.
Sleep in a sleeping bag. Put the electric blanket on top of that (the sleeping bag acts as a basic insulator in case there's anything wrong with the blanket) and then put a decent duvet on top of that.
Electric blankets typically draw around 30W, but if you do it as said above you'll find that heat level 1 or 2 (out of five or six) will be more than adequate, so it'll probably cost about as much per hour as an internet box.

Safety! Electric blankets are mains powered heaters that go in bed with you. So... don't leave them plugged in while you sleep. Always use on a circuit protected by an RCCB. Don't crank it up to maximum and leave it there. A few minutes at max to get it warmed and then flip down to minimum, you'll find that's more than enough when the blanket is covered by a duvet. If you put it to max and leave it there, you could suffer serious burns. It isn't wise to put the heated blanket under you (plus your back is less sensitive to heat so you might feel colder than you are). Multiply that by a million if you're a bed wetter. ☺ Don't use if you have circulation problems or nerve damage, as your concept of what is and isn't warm may be quite out of whack.

### Fridge (simple fridge with cold box at the top)

This is the frightful one.

Extremely difficult to calculate. Most fridges have a simple mechanical temperature sensor inside, and this actually varies quite a lot depending on the ambient temperature.
However, as a broad approximation, they tend to run for about five minutes in fifteen, or about twenty minutes per hour, drawing around 300W. Which means about €0,11 per hour continuously, or about €0,04 in actual use. Over the course of a year, this could be €350ish.
Unfortunately, there isn't really an alternative unless you really like corned beef and the taste of UHT milk.

### Billing

One final note - if you have a smart meter, do not pay by Direct Debit. It seems that the energy companies are still debiting for imaginary "estimated usage" which is unjustified (and should be illegal) considering that you have a meter telling them exactly how much you're using on a daily basis.
You can usually pay by plastic on either the company's app or their website. Okay, it's not automatic, but you'll be paying for exactly what you have used and not some plucked-out-of-their-arse figure that is absolutely guaranteed to be more than your actual consumption.

And... since it only costs three centimes in electricity, I think, after writing all of that, that a good strong cuppa is what is needed now.

Please note that while I check this page every so often, I am not able to control what users write; therefore I disclaim all liability for unpleasant and/or infringing and/or defamatory material. Undesired content will be removed as soon as it is noticed. By leaving a comment, you agree not to post material that is illegal or in bad taste, and you should be aware that the time and your IP address are both recorded, should it be necessary to find out who you are. Oh, and don't bother trying to inline HTML. I'm not that stupid! ☺ ADDING COMMENTS DOES NOT WORK IF READING TRANSLATED VERSIONS.

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