Apr 06 2009
Home Energy Scams
I was recently asked about a device for saving energy costs at home – a device for power factor optimization. I checked it out, and it indeed does have all the red flags for a juicy scam.
Techno Scams
One flavor of scam is to overwhelm a potential customer with technical information that sounds superficially impressive but which the customer is sure not to understand. There may be a kernel of truth to the science, but it just takes one technical fatal flaw to doom an otherwise plausible scheme. Examples include special audio cables that cost thousands of dollars, but do not produce any audible difference in sound quality.
A subset of these scams is to take a technology that actually has some advantage in specific industrial applications and then adapt them for residential or personal use, where they have not benefit. An examples of this is filling tires with pure nitrogen – this has a small but real benefit for trucks and large vehicles, but not for your family car.
Sometimes part of the scam is to come into the home with some gizmo and then give an impressive-looking demonstration. Home water filter salesmen are known for this.
Protect Yourself
There are some very useful rules of thumb to follow when someone is trying to sell you such a device. Do not purchase of device if you do not understand the science behind it. Do not let a slick salesmen dazzle you with technobabble. If you don’t understand the claims well enough to judge them for yourself, then consult an expert before making a purchase.
Listen to your common sense. If a claim sounds too good to be true, that’s because it probably is. Adding a magnet to your fuel line is not going to increase the fuel efficiency of your car by 30%. You have to ask yourself – if such a claim were true, why isn’t everyone using such a device. Why isn’t the government mandating that such devices are added to all cars. Imagine if we could reduce the fuel use of our automobile fleet by 30%.
Don’t believe testimonials. Testimonials are worthless, they can be invented, they can be given by people who have a stake in the company or the sale, or they could just be cherry picked and misleading. Testimonials are used because people emotionally find them compelling, but they are worthless as evidence. If a company has a link to testimonials, but not a link to published peer-reviewed scientific evidence, or to official government or industry information – then be wary.
But also – be wary of links to official government or industry information. This may be legitimate, but ask yourself if the links actually support the claim or are just provided to give the impression of legitimacy. One trick, for example, is for medical device marketers to claim that their device is listed with the FDA. This makes consumers think that the claims made for the device are FDA approved, but this is not true. Again – if you have dificulty sorting this out, consult an expert or a more knowledgable friend.
And of course – generic advice – don’t let yourself get pressured into a quick sale. Take the time to investigate. Anyone who wants you to make a decision right then is scamming you.
Power Factor Optimization
Now back to power factor optimization – what is it? This falls under the category of something that is useful for industry, but not for residential use. Companies selling this for the home, will typically impress their customers with a long, and generally accurate, description of the physics. But they leave out the little detail that dooms their claims.
In short, these devices reduce reactive force – technically volt-ampere reactive power, or var. There are two kinds of loads in an electric circuit: resistance and reactive. Resistance is what does useful work – turning a motor or lighting a lightbulg. Reactive load results from differences in the current and the voltage and essentially is wasted as heat.
Var devices claim that they balance the current and voltage (using capacitors and other methods) and therefore reduces reactive load, decreasing the amount of electricity that is wasted as heat, and thereby increasing efficiency. This, therefore, will reduce your electric bills by reducing waste electricity.
But here’s the kicker – electric companies measure and charge for only the resistance load, electricity that does work. They do not care about the reactive load for residential homes because it is generally minimal.
They do measure the reactive load for industrial use, where certain pieces of equipment may have significant reactive load. They charge a “penalty” for high reactive loads for industrial use – but not to residential customers.
Therefore the savings for a residential user should be minimal to nothing.
Some companies, like KVAR energy controller, appear to make devices that actually work, in that they may reduce reactive load. They have to be installed by an electrician at the circuit breaker box – the point at which electricity enters the house. The problem appears only to be the application to the home and the claims for electric bill savings, with only testimonials to support these claims.
Even the modest 10% savings they are claiming would be huge if employed nationwide. If it really worked I would think it would either be mandated, or supported by a tax refund or other incentive.
There may also be outright fraudulent products out there also. I recently received this e-mail from an SGU listener:
Last year I was visiting my mom and she had an appointment with some people to come over and check her house because they could “save her money” on her electrical bill. Of couse when they showed up I was immediatly asking for specifics about what they did. They had all kinds of fancy words and equipment, but here is the jist. The lady pluged a device with a small LCD screen into the wall sockett and said, “Ooohhh…” then told me that the current in the line was jumping up and down really bad. She also threw in some “wave” and Diffrental” words She then pluged a capacitor into another plug on the same circuit and showed me her little LCD readout witch had droped to neer zero. She told me that the capacitor would store all that wasted energy “noise” and smooth out the flow in the lines, then release it later. Thus saving up to 30% on your energy bill. I was astounded, mostly that my mother and stepdad would let these people within 100 yards of their front door.
A device plugged into an outlet would not plausibly achieve power factor optimization, so this is a scam of a scam. But we see here the typical ploy of doing the in-home demonstration combined with some technobabble and some impressive claims – 30%, wow.
Conclusion
I had to spend some time investigating this one. The basic concept of installing a device at the junction box to reduce wasted electricity sounds superficially reasonable. There are advancements in effiiciency all the time as the technology evolves. Home appliances and electrical circuits today are generally more effiicient than they were 50 years ago. Just like cars today are much more fuel efficient than those of the past (although in the US they are also bigger on average, offsetting some of the advantage in fuel efficiency).
Also – the back story of reactive vs resistive loads is all correct. But still, the extraordinary claims and the marketing style set off my skeptical alarm bells. The devil is in the details, and in this case power factor optimization seems to be useless for residential use, although legitimate for certain industrial applications.
I also acknowledge that I am not an electrical engineer, and some of the technical websites I consulted exceeded my basic knowledge in this area. So if there are any electrical engineers out there – please add any needed detail or corrections to my summary.
But I followed my own advice – I consulted the experts, and my summary above is what they had to say.
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18 Responses to “Home Energy Scams”
I can tell you that using a capacitor to smooth out power lines is a real technique but the context in which you described is totally false. Unless you are using extremely sensitive equipment in your home, small scale power fluctuations are not going to do anything.
Steve:
The following explanation of resistive power, reactive power, and power factor may be helpful.
AC voltage is transmitted as sinusoidal waveforms with a frequency of 60 hertz, so think of classical sine wave patterns when thinking about AC power. In a purely resistive load, such as an incandescent light bulb or an electric oven’s heating element, the AC current through the load is “in phase” with the voltage across it. In other words, if the current sine wave is overlayed on top of the voltage sine wave, the two waves peak at the same times (and with the same polarity) and cross zero at the same times. For this type of circuit, the power factor is equal to one, because the product of the RMS voltage and the RMS current equals the actual power (called “real power”) delivered to the load.
Capacitors and inductors behave very differently compared to resistors. These are called “reactive” devices, and they are capable of storing and releasing energy during every period of the source voltage. Capacitors store and release energy in electric fields, and inductors store and release energy in magnetic fields. The energy-storage characteristic of reactive loads causes the current waveforms to be phase-shifted relative to the voltage waveforms. For capacitors, the current sine wave “leads” the voltage sine wave by 90 degrees. For inductors, the current sine wave “lags” the voltage sine wave by 90 degrees.
If you look at these “out-of-phase” voltage and current waveforms of purely reactive circuits and multiply the voltage and current at each point in time, you will see that the resulting power waveform is a sinusoid that oscillates above and below zero watts. In other words, half of the time, the reactive load is consuming power, but the other half of the time, the load is returning that power to the source. Therefore, the net power delivered to the load is zero, and so is the power factor. If you just multiply the average (RMS) voltage by the average (RMS) current, you will obtain an “apparent” power of much greater than zero. However, that apparent power is doing no work, and ideally you don’t want to have to pay money for it.
Real linear circuits are usually combinations of resistive and reactive loads, so their resulting current waveforms lead or lag their voltage waveforms by angles less than 90 degrees. For these circuits, the power factor is somewhere between zero (which represents a purely reactive circuit) and one (which represents a purely resistive circuit). By adding the appropriate reactive load (i.e., inductors or capacitors) to such circuits, we can compensate for their current phase angle and bring the power factor closer to one.
Also, I should mention that the explanations above apply to linear circuits, which are circuits composed only of resistive and reactive elements. In reality, many electrical devices used in our homes are non-linear, and they produce non-sinusoidal currents. For example, power supplies that convert AC voltage to DC voltage to power things like computers use switching components (such as diodes), and therefore create non-linear current waveforms. For these circuits, power factor compensation is more complex than just adding capacitors or inductors to the circuit.
Regarding tax breaks for efficiency, very true. In Toronto, you can get a break for installing more water efficient toilets etc. In Ontario, you can get those neon replacement bulbs at a subsidized price. Yeah, anything that would add an across the board 10% efficiency would have public utilities doing back flips and tripping over themselves getting you to install the device and helping pay part of the cost.
C’mon guys, don’t you know it’s just big electrical flexing their muscles. The more energy we waste, the more they sell.
Watcher – I know you are joking
, but I ran across some sites saying that. However, since the electrical companies do not charge residences for reactive load, waste through reactive load is a pure loss for them. Reducing it would be a pure gain.
Ahhh I see. I’m just glad my sarcasm could add something to the conversation
Mostly because you pointed out a distinction I’d missed!
Although it’s amazing that people are jumping on the conspiracy bandwagon already … Well, not really I guess.
I’m not an electrical engineer, but I have worked in the home improvement/repair biz for my entire adult life, and have worked for stores that sell various incarnations of this sort of crap. And belive me, it’s all crap, for the reasons you note and more. Anything that will “save you xx%” on your “fill in the blank” bill every month is a scam, especially your electric bill. There isn’t an electric utility in the US that isn’t overloaded (if one is, they all are, cuz they’re all connected), and power outages due to equipment failure costs them far, far more than people reducing their monthly bills 10% would. Electric companies would be first in line to offer rebates on such devices if they worked – as they do with CFL bulbs. They are often subsidized with tax dollars in doing so, but not always.
taustin: I am an electrical engineer, I can tell you for sure, turning that one really big switch in your breaker box off will save you 100% on your monthly bill
But seriously, the question is: why does the power company care about reactive loads?
I can connect a huge ideal capacitor (or inductor) to my outlets, and it won’t dissipate any power. Zero. Zilch. Nada. By ‘ideal’, I mean there is no resistive component. As Jim says above, it will store energy during half the cycle, and give it back the other half cycle.
But, the reason they care is that you’re pulling current in during half the cycle, and pushing current back out to the grid during the 2nd half cycle. And even if my capacitor/inductor is ideal, the wires between the power company and my house are not. They are resistive.
So, even a pure reactive load in your house will consume power in the power company’s distribution grid, following Ohm’s law: P=I*I*R, where
P = power (Watts),
I = current
R = resistance of the wires between your house and the power company.
(BTW, you can see from the above equation why the power company uses high voltage transmission lines. By using a transformer to trade off high voltage for low current, they use less current, and thus incur less I^2 * R losses during long distance transmission.)
Thanks, ccrome. I was also going to include a description of the transmission line I^2*R losses that occur no matter how reactive the load is in one’s home, but I thought my post was probably too long already. (^_^)
If your power company is only charging for resistive power, then yes, PFC won’t do anything for your pocketbook. However, anything other than a power factor of 1 does waste energy. You just aren’t being charged for it. Power factor correction won’t save much power per home, but if it was done across the nation or world, the energy savings would be huge. Since when is it all about the money in your pocket?
Most homes would have an overall lagging power factor due to the inductive loads. That means that you add a capacitor in parallel to raise it closer to 1. Would it be ideal if you have non-linear circuits as mentioned above? No, but it would definitely help. And yes, you CAN plug it right into an outlet because it only needs to be in parallel with the inductive load. It would be a trivial matter to make a capacitor bank with a microcontroller that performs real time PFC.
Min – No one said it’s all about money. The point that the power company does not charge for reactive loads was to counter the charge they they are not interested in increasing efficiency because they make money from selling electricity.
If such devices could increase efficiency then power companies would have a huge incentive for every home to have them. Heck – why not just install them at the transformer? This would be a total win for the electric company.
The fact is – such devices simply do not work. In order to be useful a reactive load optimizer would have to be built into and specific for each electronic device to optimize its efficiency. High end appliances already do this. Specifically, such devices need to be on only when the appliance is on, so it can’t just be attached to the house and always on.
See: http://energystar.custhelp.com/cgi-bin/energystar.cfg/php/enduser/std_adp.php?p_faqid=4941&p_created=1204908170
Turning off the lights when you leave the house probably saves you as much as these devices claim.
It like my dad always said, “Electricity doesn’t grow on trees!!!”
And when I got to high school, I told him it did in a way … that was a dark three weeks
Along the same lines, “Mr. Free Energy for Christ” Dennis Lee appears to have been busted on Dateline NBC:
http://www.msnbc.msn.com/id/29899191/
I believe SGU has talked about this character before. He tours the USA trying to sell dealerships in his free energy devices, does it from the pulpits of churches, claims big oil is trying to keep the honest christian down…
Steve,
You said that reactive power is wasted as heat. That’s not quite correct. The reactive power is referring to stored energy. This is either inductive or capacitive. Inductive is referring to storing the energy in a magnetic field and capacitive is storing energy in an electric field.
In my electrical energy classes we write AC voltage as a vector (meaning it has components). It has a real component and an imaginary component. The real component is the resistance and is unrecoverable. It’s analogous to friction of a ball rolling up a ramp. The imaginary part (represented with ‘j’) is the stored energy. This is analogous to the ball rolling up the ramp is slowing down and storing energy as potential that can be recovered by rolling back down the ramp.
I would express the voltage like this:
V=[1 + j5] – this would represent an inductive voltage (energy stored in a magnetic field because of the ‘+’ j term)
V=[1 - j5] – this would represent a capacitive voltage (energy is stored in the electric field because of the ‘-’ j term)
So the reactive component is just stored energy and what is dissipated as heat is the real part. If a circuit is purely reactive, no power is lost. It’s just transfered from an electric field to a magnetic field forever. Just like a frictionless pendulum transfers it’s potential energy to kinetic energy forever.
If you would like to reduce your electric bill by 30%, contact your state’s utility consumer advocacy agency. In Illinois, we have a a citizen’s utility board.
I am also an electrical engineer, but my area of expertise is not power distribution however I do understand the whole reactive and resistive load concepts. I had multiple courses that covered these concepts, but no practical experience. My understanding has been that the electrical power meters on our homes do not distinguish between reactive and resistive loads. It just multiplies the amplitude of the voltage by the amplitude of the current and integrates this over time to get the KWhr used. If this is indeed the case, then some of the arguments and description above are technically a little off base. I would appreciate someone in the residential electrical metering business to fill in the details of these meters. Do they in fact ignore reactive loads and not charge for them. If they calculate the KWhrs as I describe they do not completely ignore the reactive loads. In fact if your load was 100% reactive corresponding to a power factor of 0, then you would be charge fully for the reactive load and not getting any energy for it except a minor amount of heat loss in the wires.
I assume that if the meters are not distinguishing between reactive and resistive load it is probably because the vast majority of residential customers have an electric load with a power factor of nearly 1.0 (mostly all resistive). I would also guess that it would cost more to make a meter that was power factor aware, and probably not worth it.
I sure would like to be set straight on all this. Can anyone comment on this?
I actually do work in this field, and I can also agree that this is bunk. I looked at that energy savers website, and although all of their math and science (so to speak) is not untrue, the application of it to residential is pointless.
Adding capacitors will reduce your total current, but only if you match the capacitance to the size of the corresponding inductive loads in your house, these being things like the motors in your fridge, drier, air conditioners, etc. Now, realize that these things don’t run 100% of the time. So unless you have equipment to detect what your inductive load is and automatically adjust the amount of capacitance to add, you’ll probably overcompensate as often as you are improving things. Someone else mentioned that utilities don’t like this, and I can confirm that they don’t. it’s a lot easier for them to manage the grid when they control things like how much reactance is out there.
Which leads to the fact that the utilities DO control this. Utilities will place static (non-varying) capacitors throughout their system to make up for the total inductive loads presented by their customers, and also have larger adjustable capacitor banks that can be switched in and out as required. It makes sense for the utility to do this, as an aggregated group of 50-100 houses will average out to a far more stable load than a single house with all those motors switching in and out…