Energy Saving Trust

@EnergySvgTrust

A quick way to #saveenergy at home is to turn off tablets, laptops and consoles as soon as you stop using them, and ideally unplug them.

This is a big potential #energy saver and could save you up to £30 a year.

Find out more here:
ensvgtr.uk/pS1ut

#EnergyEfficiency pic.x.com/q2CWdlkaBH

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This is known as "Vampire Energy" and, amusingly, is a bit of a Zombie statistic. Being the party-pooper that I am, I emailed the Energy Saving Trust to ask how they calculated the stat. They replied quickly with:

The calculation for £35 savings from turning off stand-by devices per year per household comes from average 201KWh for stand-by power times GB average standard electricity price 16.471 £p/KWh, then rounded to nearest £5.

201KWh comes from “Further Analysis of the Household Electricity Survey Early Findings: Demand side management”.

Please note that the term “stand-by” used in this situation also include device on idle mode.

Please refer to the report in more detail about the assumptions used in the analysis. Here is the link for this report: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/275483/early_findings_revised.pdf

OK, let's take a look at the 2013 report.

First up, what disclaimers do they have?

Straight away they say that it's hard to measure low power devices - so they've been rounded up. But at least they're honest about their methodology.

So, what devices did they monitor?

I'm not sure how many people were still using VCRs back in 2013 - Dixons stopped selling them in 2004. I'd bet hardly anyone uses them now. If you still use one - please switch it off at the wall when not in use!

Set top boxes still exist - but most TVs now have digital decoders built into them. When the TV is on standby, the "STB" is also on standby. Drawing a tiny amount of electricity. But, OK, not everyone has a new TV.

What about things like Sky boxes? Well, the report mentions two issues:

Yes, you can switch these boxes off at the wall - but then they won't record the programmes that you want.

As the report was being published, Sky updated their boxes so they'd be eco-friendly. I'm told that this mode is now the default - but it may be worth checking to see if your devices have an "eco" setting. That will do more good than unplugging things.

It's not just AV equipment contributing to this "vampire" power. Computer equipment is also included:

Again, the report acknowledges that things like modems and routers don't really count as "standby" because they can be in constant use. If you want to check your TikTok in bed, you don't want to have turned off the WiFi.

Laptops have a high average "standby" because they use the first few hours charging their batteries. So, again, legitimate use rather than "vampire" use.

The report also looks at things like microwave oven clocks, tumble-dryers, dishwashers. Some of these do use a considerable amount of standby power. Although resetting the clock on the microwave every morning may not be the best start to your day.

That all feeds in to the 201kWh per year figure.

There's also some discussion about the idle power for things like doorbells, smoke alarms, burglar alarms. They have a significant power draw - but I don't think anyone would suggest that it is sensible to switch off your alarms overnight.

Remember that original Tweet?

Energy Saving Trust

@EnergySvgTrust

A quick way to #saveenergy at home is to turn off tablets, laptops and consoles as soon as you stop using them, and ideally unplug them.

This is a big potential #energy saver and could save you up to £30 a year.

Find out more here:
ensvgtr.uk/pS1ut

#EnergyEfficiency pic.x.com/q2CWdlkaBH

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It suggests turning off tablets - which are not included in this report. Go buy a cheap Watt-meter and see how much "vampire" energy it is using. Once the battery is fully charged, it will use very little.

Similarly, laptops - even older ones - won't draw too much electricity once they've gone to sleep.

Consoles? Sony publishes stats for the PlayStation. Some of the older ones will use up to 4W in "rest" mode. That allows the device to check for updates and to power on quickly. If you switch it to low-power mode, it'll use less than a Watt.

This "advice" is bunkum.

Should you switch your devices to "eco" mode? Absolutely! Will it save you £30? Not even close.

Update - 27th April 2022

This zombie stat is doing the rounds again today. Here's a Twitter thread where I go into a bit more detail about it.

Terence Eden is on Mastodon

@edent

I looked into these claims when they were made last year.

It is mostly nonsense.

Here's what I found shkspr.mobi/blog/2021/10/n…

Sadly, the BBC don't link to the original British Gas research.
Pushing responsibility onto the consumer is, ironically, gaslighting.None

BBC News (UK)

@BBCNews

‘Vampire devices’ cost UK households £147 a year bbc.in/3xX0yOY

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It's been ages since I did any real electronics. Most of my work involves software and pre-assembled bits of kit. I thought that it was time I reacquainted myself with the joys of electricity :-)

Because I'm fundamentally lazy, I purchased the all-in-one Raspberry Pi 2 kit from Vilros.

Lots of LEDs, some buttons, a nice case, all the cables, resistors, and all sorts of bits and bobs. Including a breadboard!

What's A Breadboard?

I remember - from school - that a breadboard is a.... thing... that lets you... electricity?

Honestly, it wasn't until I saw this diagram from Adafruit that it all finally clicked into place:

Aha!

The kit comes with a T-Shaped Cobbler which fits onto the breadboard and means you have a neatly labelled system with fewer wires running about the place.

I followed a sample tutorial on how to wire in an LED to be permanently on. Basically +3.3v → long leg of LED. Short leg of LED → 330Ω resistor → Ground.

Ok, that was easy. Now lets make it flash on command!

The wiring is fairly similar, but we use a controlable GPIO pin instead.

GPIO pin 21 → long leg of LED. Short leg of LED → 330Ω resistor → Ground.

Here's what it looks like:

And here's the Python code to switch it on, then off.

import RPi.GPIO as GPIO
GPIO.setmode(GPIO.BCM)
led = 21
GPIO.setup(led, GPIO.OUT)
# Switch on
GPIO.output(led, 1)
# Switch off
GPIO.output(led, 0)

Wooo!

Ok, so, next thing - how to get information in to the Pi?

I was confused about exactly how the push switch worked - why were their four pins?

I read the O'Reilly Raspbery Pi Tutorial and became enlightened.

So, lets create a thingumy which lights up an LED when a button is pressed.

The LED will be the same as the above. The button will be wired as: GPIO pin 19 → Button A. Button B → Ground.

And the code is:

import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BCM)

# Pin 19 will sense for button pushing
button = 19
GPIO.setup(button, GPIO.IN, pull_up_down=GPIO.PUD_UP)

# The LED
led = 21
GPIO.setup(led, GPIO.OUT)

while True:
    input_state = GPIO.input(button) # Sense the button
    if input_state == False:
        print('Button Pressed')
        time.sleep(0.2)
        # Switch on LED
        GPIO.output(led, 1)
    else :
        # Switch off LED
        GPIO.output(led, 0)

I'm not entirely sure why if input_state == False: is the logic for the button being pressed. Seems like it ought to be True, no? Anyway, there's a long discussion about all the ways sensors can be read on the raspberry-gpio-python pages.

Well, there you have it. An utterly simple guide to getting started. I just hope future-me finds this useful!