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Flying Rodents

By January 24, 2012November 9th, 2021Energy Efficiency, Energy Rant

Before I get to this week’s rant, or I should say, this week’s primary rant, I need to share this with you.  Just before the holidays in Strange Magic,I tore into hands-free energy audit software.  All you need is an address and billing information and voila, there it is; an energy audit that tells you everything you need to know to cut your energy bills by a certain guesstimate.

This week I came across an apparent competitor to the one discussed in Strange Magic, so I viewed their online charting and graphics.  They present analysis via bar chart for various end uses; lighting, cooling, heating, miscellaneous, and so on.  They present current consumption and potential consumption for each of these, demonstrating a savings of course.  It took about three seconds for my eyes to pick up the fact that the ratio of all the end uses looked very similar.  Sure enough every single one of the seven end uses has a potential to save almost exactly 23%.  That will never happen.  It would be like every guy on a 12-player roster scoring exactly 10 points.  That isn’t how it works.  Ever.

Now dude, this is bordering on fraud if you ask me.  What did I say in Strange Magic?  The best you can do is guesstimate savings potential for the entire building with the information you can get from billing records and a street address.  Do not be fooled by this crap!

You old gray hairs like me would remember the days when they had cartoons before the movie started.  That was the cartoon, except for it is serious as a brain tumor.  On with the main attraction.

Our beloved California is once again “leading” the nation in energy efficiency policy.  This time the target is… drum rolllllll… the phone charger!  More accurately, all chargers – so-called “vampire loads”.  So this week’s rant features analysis and research conducted in my house.

I’ve seen a number of articles on this topic but this one from Energy Efficiency News seems like a good one.

This is California with 37 million people and so the numbers are incomprehensible until we start pealing back the onion.  These charger devices are reported to consume 8 billion kWh, or 8,000 GWh.  There are 12 million households in CA, averaging 11 chargers per household: 120 million chargers.  Do the math and you get 17 kWh per charger saved annually.  If they are saving energy 24/7/365; dividing 17 kWh per year by 8,760 hours/year results in 1.9 Watts saved every hour of every year for every charger in the state.  The article states that this is 40% savings, so the average charger wastes almost 5 Watts all the time according to California.  See nearby chart for clarification.

So is this reasonable?  Here are my findings using a “Kill A Watt” 120 Volt power meter:

  • My phone, Motorola Droid Pro smart phone:  Consumes about 7 Watts while charging, and turned on.  Once it’s fully charged, it cycles between 0 and 3 Watts, mostly on zero.  When the screen is turned off, you have to wait a long time before it gets a micro shot of 3 Watts.  So it uses almost nothing when plugged in, turned on, not in use and fully charged.  When it tells me it’s fully charged, unplug it to save energy, it would take 16 years to save a (one) kWh.  I’ll get right on that.
  • iPod Touch:  This thing is identical to the iPhone without the phone part.  It guzzles a whopping 3-4 Watts while charging AND in use.
  • Dell Mini Computer:  Booted up with the lid closed and monitor off uses 7 Watts.  With the monitor on, 11-12 Watts.  In use while charging full blast: 30 Watts.  Shut down with a full battery: 0 Watts.
  • Dell 4200, 12 inch laptop (my real computer): Booted up, running a bunch of apps, monitor on and charging full blast: 40 Watts.  All else equal with the battery fully charged: 16 Watts.  Shut down on a full battery: 0 Watts.
  • Rayovac battery charger with 4 AAA batteries: 3 Watts.  I don’t know how these things work exactly but they seem to consume consistent power.  The batteries are always warm – 3 Watts warm.

So first off, as one blogger pointed out, saving energy by eliminating “vampire” loads is crap.  Vampire loads don’t amount to squat.  I’ll tell you want does amount to 10% of squat: not shutting down equipment like computers, stereos, DVRs, and stuff like that.  But these aren’t vampire loads.  They are load loads for crying out loud.

The vampire loads with my electronic stuff, which has to be pretty typical of battery chargers, is virtually zero.

Back to the battery charging.  The power factor on these battery chargers is poor, at only 0.5 or so.  Could it be this is what the once-golden state is targeting?  Not so much.  Poor power factor simply requires more current on the wires from the generator to the device.  More current means more line losses.  Line losses from generator to point of use are roughly 10%.  So if we take 10% of 15 Watts (the remaining 0.5), ooh, ooh, 1.5 Watts.  Well I’ll be darned.

This is within the realm of possibility but probably not likely.  All of these 11 devices per household would have to be in use 24/7, at least (?).  The savings is probably closer to one third of that claimed, or perhaps a quarter.  The devices most likely use substantially less than 15 Watts on average – see the phone Wattages above.

But who gets the savings from power factor correction?  Not the consumer; at least directly.  Residential customers in every precinct I know of pay nothing for crappy power factor.  It all boils down to reducing losses by my guesstimate of 7 Watts per household, or a whopping 6 kWh per year per household.  You’d “save” more by reusing your towels a couple times per wash, in a couple weeks.

But remember, consumers don’t save.  It’s actually the utility that saves.  In a regulated market, some of that would flow to the consumer in the form of lower rates because the utility recovers more revenue for given assets: generation, poles, wires and fuel.  However, the amount is so tiny, it’s within the margin of error I’m sure most likely upgrading chargers is a waste of money for consumers.

Rambling on just a little more, The Washington Post report on this, calling it “vampire battery chargers,” says “Chargers waste electricity by continuing to draw electricity even when a battery is full and suck energy when laptops, cellphones, digital cameras and other devices aren’t plugged in.”

Chargers continue to draw power even when the battery is full?  Well duh!  The device is still running.  As I found in my tests, shutting down the device with a full charge and the thing plugged in results in ZERO energy consumption.  Maybe I should call Kill A Watt because their meters don’t work, apparently.  Chargers still draw power when nothing is plugged in?  None of mine do at least to the threshold of a tiny 1 Watt.

Lastly, the Times article says chargers waste up to 60% of what they consume.  What happens with this 60%?  Energy waste is almost always if not ALWAYS given off as heat.  We’ve established that laptops consume about 15 Watts provided by a “charger” – an electronic doohickey (rectifier or something like that) that converts 120 Volts of alternating current into a few volts of direct current for computer consumption.  This is the only place this ~50% waste can occur because my power cords aren’t melting.  A 15 Watt CFL from my laboratory heats up to about 160 degrees.  My charger: 85 degrees, while delivering 16 Watts.

It’s been a while since my heat transfer courses but I can promise the heat loss from the CFL is a complicated model because of the geometry.  However, it is safe to say it has a lot more surface and better orientation to enhance heat transfer.  That being the case, if both the CFL and the charger are wasting 15 Watts, the charger should be much hotter due to its small size (next to Bailey’s paw for scale) and lousy heat transfer characteristics.  So I conclude there is very little real energy loss from these devices.  To cover the phones, their charger physical size and profiles are much smaller and not warm at all.

I declare these vampire losses to be more of a flying rodent loss and somebody, preferably a team of engineers should spend a day or two, determining the real savings because it isn’t 2 Watts per charger as claimed.

And BTW, the power factor of that CFL 0.59.  Uh oh.

Jeff Ihnen

Author Jeff Ihnen

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