In the heatwave of July-August 2006, the local papers here in LA were full of reports about how our power systems are straining to keep up with demand. Actually they say we have enough power, but are just lacking in the infrastructure to deliver it. Pole mounted transformers were failing as unprecedented loads were placed on them. On one particularly sizzling day, we managed to reach a peak power consumption figure that the local power company (Los Angeles Department of Water and Power) believed would not be seen until several years into the future according to their power projections. The big load is of course air conditioning during hot weather. But the proliferation of small electronic appliances left plugged in but in "standby" condition create a significant "background" load on the system. This is the one place where consumers could choose to save power (and money on their power bills) if they realized just how much this can be.
In an effort to try to quantify this, I went around my house measuring the "standby" and "on" currents and turned this into power using Ohm's law and then into $/year using the KWH rate from my power bill. I only picked "discretionary" devices that really can be completely powered off when not required. As a general rule, any appliance with a power switch that has a solid "click" to it, probably doesn't use power in the standby mode. Any device with a "soft" power switch that just requires a light touch, or that has an infra-red remote control definitely draws power in standby, since the electronics have to be on to wake the device up when you turn it on. Most kitchen appliances like mixers and blenders and old-style mechanical toasters consume nothing when in the "off" condition. If they have a soft membrane-type control panel, there's a good chance that there's some always-on electronics inside. All those adaptors for charging batteries, cellphones, cordless devices etc all consume power when they're left plugged in but not connected to the things they're charging. These either have transformers in them, and on these you can feel their waste heat by touching them, or they have "switched mode" power supplies, which tend to be more efficient.
The only way to stop these devices drawing power is to unplug them in most cases. If everyone with a TV had it plugged into a power strip first, and then into the wall, and then turned the strip off when the TV was not used, that would save a lot of power. Ideally cable/satellite boxes, VCRs, DVD players etc should also plugged into this strip. If as much as possible is isolated and turned off when not used significant savings can be realized. The only inconvenience is the extra step to turn the strip on and off. Unfortunately Tivos and DVRs which draw a fair amount of power really have to be left on all the time. The cable/satellite company may need you to have the cable/satellite box powered up all the time too (for nightly phone calls etc). Also, manufacturers didn't really design for this, so some devices may "forget" settings - the blinking "12:00" on a VCR is an example. I have an older Yahama receiver that forgets its FM presets if left unplugged for a period. This is just lazy design. There's no excuse with any product built in the last 10 years or so - memory chips are cheap. The manufacturers of these devices really could design things better. There could and should be energy standards to be met. And they certainly should be designed so that they retain "soft" setting information when completely unplugged. Computer monitors, printers, fax machines etc all have to conform to "Energy Star" ratings. Why not other electronic devices?
Below is a table of some of the devices I was able to measure around my house. Some of the more notable items:
The DVD player that consumes 1/3rd of its "ON" state power when in standby. This means that if left plugged in 24/7, but used to play a 2 hour DVD every day, then it's actually consuming over 3 times more power when not used, than when it is being used.....and all this so you can fire it up from a remote control across the room. Of course, you had to go to it to put the disc in anyway so how hard would it be to also turn it on from a power strip??! Or better still, have a hard power switch on the front of the DVD player.
11 watts for a TV in the standby condition! That's huge.
Leaving an active subwoofer plugged in is a real waste...sucking 13 watts just sitting there. Definitely something worth only powering when the amplifier is also powered.
I was a bit mystified when I tested my new LCD TV, since I was led to believe that LCDs have a constant always-on backlight. The 332 Watts I measured accords with the 330W specification in the handbook, and was with a bright image on the screen, but with a darker picture, it uses a lot less. For instance when just the text is displayed on a satellite music station for example, the power goes down to less than half of this.
Ikea should be commended for using a very efficient switched mode power supply on the lamp.
As you can see, the "worst" offender in terms of ratio of "standby" to "on" power is the satellite box, a Sony SAT-A55 which is no longer in use. There is barely any difference between Standby and On conditions. Pretty much all standby does is shut off the video output and turn off the power indicator. Where does the power go? Mostly heat. This particular model was notorious for melting access cards. You can see that it wouldn't be hard to reach much higher than 100 watts of constant standby power in households with multiple TVs. On an individual household basis, this may not seem so much or so bad, but if every household has an additional constant 100 watts that they didn't have before, it means the power companies have to supply a whole lot of additional power.
Here is a link to a device that can be purchased for $30 which measures what I'm measuring. I'm actually using a "DMM" (Digital Multimeter) with a rig to wire it in series with the device under test, and it's set to AC Milliamps, or Amps, according to the size of the load.
