Is it “Green” or Is It Just Theft?

This is reprinted from my other blog.  I usually confine my posts on this blog to issues with the science of global warming rather than policy issues, but I know I get a lot of folks with science backgrounds here and I would honestly like to see if there is something in this I am missing:

From (via Engadget) comes a technology that I have written about before to leech energy from cars to power buildings:


Now when you shop, your can be responsible to power the supermarket tills. As in with the weight of your vehicles that run over the road plates the counter tills can be given power. How? Well, at the Sainsbury’s store in Gloucester, kinetic plates which were embedded in the road are pushed down every time a vehicle passes over them. Due to this a pumping action is initiated through a series of hydraulic pipes that drive a generator. These plates can make up to 30kw of green energy in one hour which is enough to power the store’s checkouts.

The phrase “there is no such thing as a free lunch” applies quite well in physics.  If the system is extracting energy from the movement of the plates, then something has to be putting at least as much energy into moving the plates.  That source of energy is obviously the car, and it does not come free.  The car must expend extra energy to roll over the plates, and this energy has to be at least as great (and due to losses, greater) than the energy the building is extracting from the plates.  Either the car has to expend energy to roll up onto an elevated plate to push it down, or else if the plates begin flush, then it has to expend energy to pull itself out of the small depression where it has pushed down the plate.

Yes, the are small, almost unmeasurable amounts of energy for the car, but that does not change the fact that this system produces energy by stealing or leeching it from cars.  It reminds me of the scheme in the movie “Office Space” when they were going to steal money by rounding all transactions down to the nearest cent and taking the fractional penny for themselves.  In millions of transactions, you steal a lot but no one transaction really notices.

I have seen this idea so many times now portrayed totally uncritically that I am almost beginning to doubt my sanity.  Either a) the media and particular green advocates have no real understanding of science or b) I am missing something.  In the latter case, commenters are free to correct me.

By the way, if I am right, then this technology is a net loss on the things environmentalists seem to care about.  For example, car engines are small and much less efficient at converting combustion to usable energy than a large power station.  This fact, plus the energy losses in the system, guarantee that installation of this technology increases rather than decreases CO2 production.

Postscript: One of the commenters on my last post on this topic included a link to this glowing article about a “green family” that got rid of their refrigerator:

About a year ago, though, she decided to “go big” in her effort to be more environmentally responsible, she said. After mulling the idea over for several weeks, she and her husband, Scott Young, did something many would find unthinkable: they unplugged their refrigerator. For good.

How did they do it?  Here was one of their approaches:

Ms. Muston now uses a small freezer in the basement in tandem with a cooler upstairs; the cooler is kept cold by two-liter soda bottles full of frozen water, which are rotated to the freezer when they melt. (The fridge, meanwhile, sits empty in the kitchen.)

LOL.  We are going to save energy from not having a refrigerator by increasing the load on our freezer.  Good plan.  Here is how another woman achieved the same end:

Ms. Barnes decided to use a cooler, which she refilled daily during the summer with ice that she brought home from an ice machine at her office.

Now that’s going green!  Don’t using electricity at home to cool your groceries, steal it from work!

Update: The one place one might get net energy recovery is in a location where cars have to be breaking anyway, say at a stop sign or on a downhill ramp of a garage.  The plates would be extracting speed/energy from the car, but the car is already shedding this energy via heat from its brakes.  Of course, this is no longer true as we get more hybrids with dynamic breaking, since the cars themselves are recovering some of the braking energy.  Also, I have never seen mention in any glowing article about this technology that placement is critical to having the technology make any sense, so my guess is that they are not being very careful.

16 thoughts on “Is it “Green” or Is It Just Theft?”

  1. This suggests a wonder perpetual motion machine. Let’s have hydrogen fuel cell cars drive up a hill, and on the way down drive over a series of these “energy recovery plates”. We can then use the electricity they generate to crack water and generate hydrogen to fuel the cars.

  2. As soon as I saw the picture, I had the same reaction you did — the cars have to be providing the energy. Definitely not a green solution if it is on level ground. I do think there could be something to your idea of placing the energy absorbing device in a place where braking is required anyway. Perhaps something could be made of that?

    Using the freezer to cool the “fridge” is a hoot. The main savings they are realizing come from two sources: (i) the cooler is way smaller than the fridge was, so there is far less space to keep cool, and (ii) the freezer is in the basement, which means it is likely in a cooler place than the upstairs fridge was, thus requiring less energy than if it were in a warmer location. So great, they’ve downscaled their consumption by going with a much smaller “fridge” and by using their own muscular energy to schlep the ice upstairs and water downstairs on a regular basis. I feel so guilty, I’m almost tempted to unplug my second fridge in the garage!

  3. Where there are currently speed bumps may be a location where the extra energy being used might be a good location provided that the speed bumps would be there whether the generation device were there or not. I have seen these in some shopping areas that get enough traffic to possibly make it worth a shot but as far as being green I would not call it that due to the combustion engine that is one of the least effecient means of power production in use today.

  4. A ridiculous rube goldberg approach to capturing electricity.
    Unless there was some sort of solid state piezoelectric generating material that would make a potential when pressed by the cars, it would be hopelessly complicated and inefficient- an expensive, ineffective stunt.
    Here is on Rube Goldberg device
    And here is another, which like the goofy idea presented by our AGW friends, is also a fantasy:

  5. I think that you are quite correct in stating that getting the car engine to do extra work and harvesting the energy, this is stealing. It reminds me a little of the idea of placing an induction coil near power lines. Now if the wasted energy of the engine were harvested instead, perhaps making use of the waste heat, that would be legitimate.

  6. Hunter:

    Oh, My! That is one very fantastic machine! Many thanks for that link!

    But back to the original thread…

    Any approach like this to harvesting energy can never be “green.” You might be able to build it so it doesn’t constitute theft, but even so, I can’t imagine that the benefits would ever outweigh the costs of operating and maintaining this contraption.

  7. Please–the word here is “braking”.

    And the other word is “theft”. Pure and simple.

    When the car is stopped, what is it going to do next? Sit there forever?

  8. Dave K: re. your comment on costs.

    I checked the linked articles to try to find some numbers. According to the Guardian article, the devices (how about calling it ‘The Highwayman’?) planned by UK councils cost between £20,000 and £55,000, and ‘generate’ 10 to 36kW, equivalent to between £5,840 and £21,024 a year. Accepting these figures, you could argue that they will pay for themselves in 3-4 years, but in much the same way that a machine-gun can ‘pay for itself’ rather quickly if used to hold up banks. The articles are full of breathtaking rubbish from the inventor and from someone described as Sainsbury’s ‘Environment Manager'(!)about ‘green’ and ‘free’ energy, completely ignoring the fact that you have to drive large numbers of cars over them to make them work! If they are so convinced, they could buy one themselves and fit it to their drive, then spend the day driving backwards and forwards over it – think of all the free energy they could generate!
    And I thought that the ‘green lobby’ had lost the power to surprise me!

  9. Jim Turner:
    Thank you for the figures, but I am not sure that we have all the relevant numbers. I can believe that a device can cost between 20K and 55K pounds, but it is difficult to believe that this includes installation costs. Also kW is a measure of power — not a measure of energy usage. Typically, commercial and industrial customers pay both a fee for power and a fee for usage — residential customer typically pay only for usage. The devices may very well not affect the power portion of the commercial building’s bill.

  10. I got intrigued by the refrigerator vs. freezer topic, so I looked up some figures. I read the New York Times article and it looks like in order for the Mustons to live guilt-free they’re practically going back to the way their parents lived (using the old ice box), except they’re creating their own ice. Kind of makes one wonder how much energy it takes to do that…

    They are falling into what a lot of people caught by “green” are caught up in: feelings of energy guilt. It looks to me though they may not really be thinking about what they’re doing. According to the article their old refrigerator used 1300 Kwh/yr.

    According to Public Service of New Hampshire ( here is what they said about stand-alone freezers in the chest configuration, 17 cu. ft.:

    regular: 173 Kwh/mo. (x 12 = 2076 Kwh)
    frost-free: 216 Khw/mo. (x 12 = 2592 Kwh)

    These use more power than their old refrigerator! It’s difficult to find other energy rating data. Maybe there are smaller freezer units than this and that’s what the Mustons are using. But this should give one pause. People should really check on the energy your appliances are using if you’re going to make a decision like this.

    Here are some refrigerator configurations that probably would’ve saved more energy than what the Mustons have, based on what NH Public Service said. Modern refrigerators are much more efficient than the older ones:

    This list is apparently refrigerators without separate freezer spaces:

    14 cu. ft.: 65 Kwh/mo. (x 12 = 780 Kwh)
    14 cu. ft. frost-free: 91 Kwh/mo. (x 12 = 1092 Kwh)

    So one can surmise that if they had simply replaced their refrigerator with a more energy-efficient model they’d actually be accomplishing their goal, saving on their energy bill, and not inconveniencing themselves. 🙂

  11. I guess I shouldn’t come down too hard on the article. It cites other people who explain the facts about modern refrigerators. Here’s a quote that even beats what I said above:

    “Mr. Campbell was surprised to read online that refrigerators do not use all that much energy. Marty O’Gorman, the vice president of Frigidaire, said an 18-cubic-foot Energy Star-rated Frigidaire refrigerator uses about 380 kilowatt-hours a year — less than a standard clothes dryer — and costs a homeowner $40, or about 11 cents a day.”

    Here’s another:

    “It’s this sort of practical calculus that has led many who advocate sustainable living to view unplugging the fridge as a dubious practice. They point out that it is likely to result in more trips to the store (which burns more gas, for those who drive) and the purchase of food in smaller portions (thus more packaging).”

    This really makes me wonder whether the Mustons have turned into worse polluters than before while thinking they’ve gone “green”. 😛 It’s painful to watch irrational people do what they do thinking they’re doing good. All one can do is shake one’s head in disbelief.

  12. This is a great idea. I still think things like installing geothermal systems instead of conventional heating and cooling systems is the way to go though. I mean it saves energy instead of trying to find more and more ways of generating it.

  13. Great site. I hate to diagree with your conclusion in my 1st comment, but this does look like a useful system to me. My gut reaction was probably like yours, that the machine was relying on the vehicle to expend kinetic enegy to climb a ramp, which would compress a spring that the machine would ineffeciently covert to kinetic energy for the store, with a net energy loss, and an unhappy Gaia. However, after a second look, I believe what’s happening is the vehicle has a forward momentum when it pulls into the parking spot. That momentum normally has to be stopped by the driver by braking, but the store’s ramp helps the vehicle to slow down, microscopically reducing your car’s brake wear and tear in the process.

  14. I don’t know about the US but in the UK, most supermarkets have parking systems – some now photograph your car as you go in and leave to check that your not overstaying but most have the routing stop and get a ticket type. The mechanical systems break down frequently.

    The Sainsbury system assumes that, irrespective of the “theft” aspect, that these systems will work all the time. A bit like the wind farm enthusiasts who always quote capacity and never output.

    Of course the other hypocrisy is that the supermarkets know that they need large flat carparks provided free to make the store viable and thus encouraging car use plus the useful benefit of concentrating rain to increase the risk of flooding.



  15. This is so funny… but there is so much more to tell. I was attending the 31st annual “Health and Harmony Festival” in the heart of Sonoma County, California (don’t ask how I got there…)

    Of course this is dominated by Obama worship, green politics, vegitarianism…. and of course getting high and dancing to live music as a means to “change the world” after you are done buying your $30 tie dye shirt.

    On the stage, the MC of the show, between musical acts, asked the crowd of thousands… “How many of you have cell phones!?” and then offered this bit of trivial “knowledge”: “Where is the best place to recharge your phone… in your car, or at home?”

    Of course she advised the stoned masses that they should charge their phones in their cars… because “there is this little generator in there, which is running anyway, so you should use the free energy coming from it!”


    A dancing hippie stepped on my lower lip as my jaw dropped. A woman dressed as a sunflower told her car driving “earth first” fan club to use gasoline to charge their phones.

    My plan is to get an electric car without batteries, and tow a gas powered generator behind it to power the thing directly. That way I get to claim that I am green, AND use the commute lanes for being so environmentally friendly.

    Why is it that support for global warming theory relies so heavily on stupidity?


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