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Free Energy! Tell me how my design is flawed

  1. Jun 7, 2004 #1
    It’s so simple to produce unlimited, clean electricity that my design must be flawed. Let me know where my thinking has gone astray.

    This is a gravitational generator that uses the Earth’s gravity to produce electricity. We start with a standard turbine generator such as those used in windmills. The next component is similar to a mechanism in a child’s “top” toy in which downward pressure is applied to generate the spinning motion. The downward pressure is generated by a large mass/weight attached either directly above the turbine or connected indirectly via pulleys and cables. Similar to the physics of a coo-coo clock, the escapement mechanism needs to be finessed by a clever mechanical engineer.

    The key to this system is the mechanism that efficiently resets the heavy mass to yield more than one “round” of electricity. Drum roll please. And, the winner is the ancient yet all too under-utilized fulcrum and lever system! In an automated system, when the mass needs to be reset, electric motors would move counter-weights along the long lever (or levers) to reset the mass at its optimum height.

    Viola! Free energy. Is the reason no one has thought of this before because it doesn’t work? Dios mio! Did I just give away potentially millions in technology licensing fees? Oh well… ;-).

  2. jcsd
  3. Jun 7, 2004 #2


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    And have you ran the calculation to find out how much energy is required to reset the thing?

    [tex]\Delta E <0[/tex]

    You have created a perpetual motion machine of the first kind. You have violated the first law of thermodynamics.
  4. Jun 7, 2004 #3


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    Do the bookkeeping --- then wire Stockholm.
  5. Jun 7, 2004 #4
    I'm great at ideas. But, with the math... its not that I'm bad, I'm just unfamiliar with the math needed here. So... uh... er... help?
  6. Jun 7, 2004 #5


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    Potential energy is mass times G (9.8m/s/s) times height. Pick some hypothetical values for the size of your machine and calculate the energy gained by dropping the mass a certain distance. Then calculate the energy required to raise it back up. Add 20% to the second number for losses in the generation of useable energy. Compare the two numbers.
  7. Jun 7, 2004 #6
    You don't even really need any math. It's a perpetual motion machine of the first kind, violating the first law of thermodynamics: the conservation of energy.

    If I understand your device correctly, the falling mass turns a generator to create electricity, stored in a battery, perhaps. You plan on using that same electricity to again raise the mass and reset the cycle.

    In a perfect world where energy could be converted with 100% efficiency, you could convert all of the mass's initial gravitational potential energy into electrical energy. Then, you could raise the mass to its original height by exhausting all of the electricity you generated. This would be converting the electrical energy back into potential energy. However, even in the impossible perfect case, you'd only be right back where you started: mass at its original height and your batteries empty of energy.

    In the real world, you'll lose energy in this process, since you can't convert all of the mass's potential energy into electrical form, and you can't convert all of your electricity back into potential energy. There are losses along the way that you can never entirely minimize. In the best case, your device might run for a long time (like a grandfather clock can tick for a long time), but it would die down eventually, and there would never be any net output of energy.
    Last edited: Jun 7, 2004
  8. Jun 7, 2004 #7
    Okay, just to provide a visual... in the "3rd world model" I envision a person averaging 150lbs climbing to their roof, stepping onto a platform attached to the end of a 30 or 40 foot lever and pressing a button which drops them down to the ground and resetting the 1000 lb weight. I only mentioned the "automatic model" for the lazy, overweight, American audience. I will try and post the math tomorrow.
  9. Jun 8, 2004 #8
    a 150lb person on level does not balance a 1000lb weight on the other end

    if you're talking offset fulcrum then your 40 ft tall person coming down would probably only raise the 1000lb weight about 10 ft on the other side

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    Last edited: Jun 8, 2004
  10. Jun 8, 2004 #9
    I'm thinking more in terms of a "crowbar" style lever -- perhaps with a winch at the end to reset.

    Height/distance is the battery in this mechanism.
  11. Jun 8, 2004 #10
    If you use a person to reset the device, then it's not a perpetual motion machine. The person's work is input of energy into the system. His work is converted into the potential energy of the mass when the device is reset, and then into electrical energy when the mass falls. If you've got a man in there constantly resetting this lever, he's producing the electricity. You might as well have him on an exercise bike hooked directly to a generator.

    However, I don't think you really intend for this to be a human powered generator. You're still trying to cheat conservation of energy. You have to realize that whatever mechanical mechanism you devise to reset the mass (fulcrum, crowbar, lever, pulley, camshaft, whatever), it takes more energy to raise the mass than you can produce in your generator when the mass falls. There is absolutely no way around it.

    Here is some math:

    A 100 kg mass is elevated 10 m. The potential energy possesed by the mass is mgh = 98 kJ. You might be able to capture and store 80% of this energy in your battery. So you have 78 kJ in your battery.

    Now it's time to raise the mass again. If the mass started with 98 kJ of potential energy, it takes 98 kJ to raise it again. It doesn't matter who or what mechanism raises the mass, you will always need 98 kJ. You clearly don't have enough stored in your battery to raise the mass all the way, so you need an outside source of energy.

    Due to inefficiencies, again, perhaps only 80% of a man's muscle energy might be converted successfully into the potential energy of the mass. So the man would need to expend 123 kJ to reset the lever and raise the mass.

    Total system input: 123 kJ. Total system output: 78 kJ. Efficiency: ~ 63%. There's no free energy here. In fact, you lost energy in the process.
    Last edited: Jun 8, 2004
  12. Jun 8, 2004 #11


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    Great idea, and I am sure it works as you say.

    But don't lose your valuable patent. Instead, I will handle all of the mundane paperwork for a small fee. Send me $5000 today before anyone steals your brilliant idea (I prefer Paypal...)


  13. Jun 9, 2004 #12
    My Bad: I now understand the first law of thermodynamics. Thank you. However, my original concept was far less grand than a perpetual motion machine, which this certainly is not. I think the concept got lost in my phrasing of “free energy” and “automatic system”. I now understand that this mechanism cannot run “automatically”.

    My original idea was simply to create a generator that was clean and utilized a renewable energy source. While resetting weights would probably not appeal to an American market, there are parts of the world that cannot afford costly solar panels or where wind generation is not practical. Like resetting a grandfather’s clock, resetting the generator weights would become a daily chore.

    So my question still persists, can a generator based on gravity be built that would supply enough electricity for a modest house for say one day?
  14. Jun 9, 2004 #13

    Chi Meson

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    As was mentioned on a completely different thread, the gravitational field can not be considered a storehouse of energy. It is a field; it is convenient to think of an field as a "condition of the space itself." Gravitational fields are called "conservative" which means that, in a perfectly fricitonless world, they give back only what you put in.

    We currently use the gravitational field to generate electric energy; they are called "hydroelectric dams." The gravitational energy is in the water thanks to the sun which evaporates water at sea level. THe extra energy of the water molecules allows it to rise to a high level in the atmophere where it condenses and falls as rain. (I know you learned "the water cycle" already, I'm just recapping it here, honestly, not being pedantic, really, let's move on...)

    Anyway, gravity is only allowing us to get back the energy from the water that the sun put into the water. No matter how it got there, anything* that is up in the air had to be lifted up there somehow.

    (* talking terrestrial things here, hairsplitters!)
  15. Jun 9, 2004 #14
    Suppose we do have all these free energy at our disposal. The question is what we going to use it for. There are a lot of free energy out there in the form of entropy but the key is how to harness it. Make it useful.

    When something is useful, it always means that it can save time and money. But money is just potential energy. It's another form of energy derived from other forms such as kinetic energy or other stored potential energy. In a materialistic world, money can also make energy. But a poor person can conserved energy by not doing anything and be at rest, by not moving and no action. He is not wasting any energy but using at a minimum just to stay alive. So, a poor is not really using energy to produce more energy. In the industrial society, energy is use to make other forms of energy with the aim that it must save time and money and still keep the society alive and continue functioning the way it wants to work.
  16. Jun 9, 2004 #15
    According to Chi, its sounds like a gravitational generator is not an efficient way of generating energy. So what about this? Perhaps the process I describe is better utilized as a "Gravitational Battery"? A clean, environmental-friendly way of storing eccess electric capacity and redistributing the power when needed? According to TALewis this "Gravitational Battery" would be 63% efficient at storing and redistributing energy. How does this compare to chemical batteries? A penny saved is a penny earned...
  17. Jun 9, 2004 #16
    Please take my numbers with a grain of salt. They are by no means exact. They were only mean to illustrate how energy is lost when it is converted from one form to another.

    You can use gravity to store energy for later release. Instead of your idea of an elevated mass, consider an elevated storage tank. If you fill the tank with water, you can later release the water and let it fall through a turbine, converting potential energy into kinetic energy and then into electrical energy.

    The falling mass and the water tank and the chemical battery are all intermediate means of storing energy for later release. Each system has its own strengths and weaknesses that can be evaluated depending on a given scenario. There are a lot of variables, and it's not easy to say that one choice is better than another without a more detailed study of the proposed process.

    I will say that batteries are not always the best way of storing energy. It depends on the situation. You might be interested in doing a Google search on flywheels. Energy is stored in a spinning flywheel in rotational-kinetic form. A flywheel is an interesting example of an alternative way of storing energy, similar to the way in which you are interested in using gravity.

    Rather than focusing on the battery, it's more interesting to me to consider the first step -- the actual means by which you propose to "create" the energy. If you're going to use a falling mass, how are you going to raise it? If you're going to use an elevated tank of water, how are you going to fill it? If you intend this to be a human powered daily chore, consider the following:

    One of the most efficient ways for a person to convert his or her muscle power into useable mechanical energy is by riding a bicycle. An average healthy person can probably reliably produce around 75 watts (0.1 horsepower) while riding a stationary bike without become exhausted. Conversely, a very light household load consisting of a few appliances (such as a computer and monitor) might consume 300 watts. This is only a fraction of what the average American household uses at any given moment.

    In order to make available 300 watts for one hour of use, a person on a bike would have to ride for four hours. This is without considering inefficiencies and losses, and it doesn't depend on the intermediate form of energy storage (elevated mass, water tank, chemical battery). There are limits on the power a human can produce that are independent of how you intend to store it.
  18. Jun 9, 2004 #17

    Chi Meson

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    The aforementioned hydroelectric dam IS a "gravitational battery," and compared to other forms of electric power generation, it is very efficient (If it just didn't destroy the entire river, it would be great!)

    A standard "dry cell" or "wet cell" battery is a device that stores chemical potential energy. A capcitor is a device that stores electric potential energy. A bucket of rocks that you haul up to the fifth floor of a building is storing gravitataional potential energy.

    The usable energy is not stored in the gravitational field itself, but in the mass that is lifted up within the field. The mass does not get the energy unless someone or something does the lifting.
  19. Jun 9, 2004 #18


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    Chemical batteries can be upwards of 90% efficient. But that doesn't mean gravity storage isn't done. There is a reservoir in Philadelphia that stores energy by pumping water uphill at night and running it downhill during the day.
  20. Jun 10, 2004 #19
    You guys are great teachers! Thank you.
  21. Jun 10, 2004 #20


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    If you wanted to have human powered generators, why even bother with the heavy weight. You could just have people walk up a set of stairs and stand on the lever that would generate the electricity. Make it fun enough, it'd be like an amusement park ride. :smile:

    One inventor created a small radio operated by winding a clock spring. Then people living in poverty who could afford this radio but not the batteries could listen to it anytime they wanted. Similar idea of being human powered but much smaller scale.

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