Energy Saving - the great standby fallacy

Three more measurements, this time power adapters connected to the mains but without the device connected.

Dell laptop adapter 7W
Apple MacBook 11W

Seems like there's scope for improvement here when no load is being placed on the transformer.

Nokia mobile phone charger 0W (below sensitivity of the meter).

I often hear that mobile phone chargers plugged in all the time mentioned are a problem. It looks like laptop power adaptors are individually more of a cause for concern, although there's probably far more phone adapters left plugged in.

Perhaps all sockets should come with on/off switches on them to save having to pull the plug in and out. Although I expect more efficient adapters will be introduced eventually.
 
George Hook had an interesting guy on this evening during the technology slot with Karlin Lillington of the Irish Times. It did blow some popular views out of the water.
Your TV uses 1% of normal power when on standby for example. Also leaving your phone charger plugged in for one year uses the same amount of energy required for one hot bath.
 
As mentioned in previous posts it depends on the device, newer ones are less likely to be wasteful.

My 10 year old CRT TV uses 16% of normal power when on standby.
 
GeneralZod said:
I often hear that mobile phone chargers plugged in all the time mentioned are a problem. It looks like laptop power adaptors are individually more of a cause for concern, although there's probably far more phone adapters left plugged in.
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I think the biggest danger with these is the fire risk if they overheat.
 
Can anyone with one of their meters check out another myth I heard which is that TVs (presumably CRTs) use a higher rate of electricity the longer they're left on?
 
Can anyone with one of their meters check out another myth I heard which is that TVs (presumably CRTs) use a higher rate of electricity the longer they're left on?

That would not make sense. As something heats up its resistance increases, so as the heaters in the tube heat up less power is drawn. If the TV kept drawing more power it has to go somewhere and eventually it would go bang.

Towger
 
Another myth is that buying A rated appliances saves loads of cash. Not so clear cut. Take a fridge, it does not use much electricity, and therefore does not have the potential to pay back the €150 extra you paid for it.
 
BlueSpud said:
Another myth is that buying A rated appliances saves loads of cash. Not so clear cut. Take a fridge, it does not use much electricity, and therefore does not have the potential to pay back the €150 extra you paid for it.
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According to the guy with George Hook a couple of evenings ago fridges and freezers do use a lot of power. A pretty obvious one, but he said tumble dryers are a disaster power consumption-wise...as any apartment dweller will confirm!
 
This has been an interesting post on a topic which interests me. It appears that a general message 'out there' is that devices use power in standby mode. Many people I know did not actually know this. They did not appreciate that televisions, computers and other devices use power at this time. So the most important thing to realise and appreciate is that stuff uses power at times wen we did not think it was doing so. As far as I am aware, even a kettle plugged into the mains draws a tiny amount of power over time. I used a meter plugged in for a couple of days and there was a very small draw of power.

The next topic to consider is the amount of power on standby. It seems to have been quite large in the past (I note 16% was quoted for an older device) but is getting smaller now. All well and good. My main point I suppose is that just because technology is reducing the amount of waste doesn't mean its not waste and that we shouldn't make an effort to reduce waste. I'm not saying that that suggestion was made here, but I get an impression that people will say to themselves (or are already saying to themselves) 'well, it's not much, I'll leave it on standby'. This strikes me as short-term thinking.

Another poster mentioned the cumulative effects of standby power for devices across the population. I thought this was an interesting point and performed some rough sums. I preface the following calculation with thenote that percentages are rounded to the nearest whole number, and will state what I believe to be reasonable assumptions as I go. I will provide links to information sources at the end of this post.

There are approximately 1,500,000 households in the state. Approximately 98% of these have televisions. Approximately 50% of households have a second television. This amounts to 2,220,000 televisions. Let's assume that about 35% are modern units with low standby ratings, and that 65% are older units with a higher energy use on standby. This gives us 777,000 units with a standby power use of 0.4 W and 1,443,000 units with a standby power use of 12 W. I think a lot of people watch too much of the box, but I'll assume that the televisions are on standby for 19 hours of each day. the instantaneous load of these televisions is (777,000 x 0.4) + (1,443,000 x 12) Watts, which is 17.6 MW. On a yearly basis this gives us 365 days by 19 hours by 17.6 MW which gives approx 122 GW hr.


There are 555,555 computers in use in households. I'll assume that the average computer is on standby for say 3 hrs each day, and that each computer uses, say, 10 W on standby. The daily standby load is 5.6 MW and the yearly volume is 6 GW hr

A similar excercise for the 1,050,000 microwaves gives 1 MW load and volume of about 9 GW hr.

My favourite is lightbulb use. Lets say that each household on average keeps 2 lightbulbs on when they don't need to be. I'll pick two 60 W bulbs for 2 hours over the year. This gives an load of 180 MW and a yearly volume of 131 GW hr

Summing standby use of televisions, computers and lightbulbs as well as inappropriate use of bulbs gives 204 MW and a yearly volume of 270 GW hr.

The volume of electricity used by the state in 2005 was 24,800 GW hr, and expected instantaneous loads are approx 5,000 MW. So we can say that use of householdstandby power in this calculation (for what it's worth) accounts for 4% of instantaneous load and over 1% of total volume of electricity. I note that I did not include DVD players, video recorders, printers and other items of equipment. I am also being generous in my use of standby figures - I suspect there are many empty rooms with televisions and stereos playing at full power.

Now, in dealing with the original points raised: the power is small as a percentage, but its not zero. It can be measured, accounted for, and controlled at the flick of a switch for very little human effort. If I had to climb on to the roof of my house while dodging flying monkey-bats to switch off the television and PC I'd say to hell with the ESB. If the simple step of moving my fundament off the sofa and over to the TV switch will contribute to a saving of 4% of the power requirement of the state, then I'll do it.

Imperator

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As with many things I think you save pennies to save pounds. Also wasting resources is the death of a thousand paper cuts. You won't go wrong turning things off as much as possible, especially if it becomes a habit.

I notice that in Europe lights that turn themselves off by timer are commonplace and much less to here. I think devices that turn themselves off should be the standard, not the exception.
 
An interesting post...well done on your calculations!

However, I think most people would say for a 1% saving they couldn't be bothered.
 
MOB said:
I have often wondered about all the fuss made of turning off lights and electrical devices. Does the law of conservation of energy have any practical meaning in a domestic setting? It seems to me that most of the energy from a light bulb is in the form of heat, so it isn't really going to waste, just because you are not there to see it: - it is still (slightly) warming the room.
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The easiest way to see this is that in an apartment block, the warmest apartments are generally those with apartments above and below, the heat rises from the apartments below, (the top floor apartments have higher losses through the walls to the air).

Similarly, any appliance that generates heat while in standby is likely consuming a significant amount of electricity while in standby. The items I've found are : old stereo system, and the transformers in the cable to a laptop and a printer (although there is no heat loss from the printer, there is heat continually lost from the transformer)...
 
Yes indeed. I have also been checking standby costs using my Electrisave monitor (www.electrisave.ie if you are interested). I am finding that our CRT TV, our DVD and VCR consume negligable amounts of power on standby.

IMHO people should focus on the heavy loads like 1) immersions, 2) computers switched on 24x7 3) tumble dryers, etc.

Once all of these are taken care of, by all means look at the stand by stuff and mobile phone chargers.

Just my 2c.

Ronnie Kav
 
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