Electricity Recycler? Stupid Question?

I was laying in bed a few minutes ago thinking about my idea to change the world, as i do every night before bed. I thought why can't or hasn't anyone made a electricity recycling generator? like why can't you take say..... a car alternator and make it produce enough electricity to run a small motor to spin the alternator as well as have enough energy left over to power devices? and then why couldn't this theory be applied to large scale generators? or why couldn't you electricly power a vehicle and somehow turn the wheels into basically 4 big alternators that generate power for the vehicle? going back to the alternator idea, is there no way to make an alternator type generator to use say 25 - 50% of its generated power to power itself and the other 50% to power devices? please point out the flaws its hurting my brain

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whatsisface10 years ago
I once saw an interesting design for a perpetual motion machine, which involved a waterfall/river powering a waterwheel which in turn powered a pump to pump water back to the top of the hill. I doubt it would work, but I might have a go one day ;-)
Generally speaking, when it's obvious that something would break one of the fundamental laws of nature, I tend to say "hm... there must be a fault in my reasoning somewhere", rather than "hm... I doubt it would work, but I might have a go one day". ;-)

I'm content to leave trying to break the laws of physics up to people who actually know far more about physics than I do. I think the chances that an "amateur" would discover something that world-altering are on the order of a billion to one or less. Last time something so fundamental happened was Einstein's discovery of special and general relativity a century ago. And he didn't exactly qualify as an "amateur".

There's plenty of really exciting science that can be done within the laws of physics as they are currently understood...
chaoscampbell (author)  Patrik10 years ago
I have a HUGE problem with your logic. granted in our day it is often left up to the "PROS" to make the big discovery but the world altering ideas that made our world possable we're those made by people who said "No, everyone in the world is wrong, I'm right" for an example the world was once thought of as square, the man who discovered it wasn't was ridiculed and laughed at because his idea went against all the ideals and laws man had set for him. I personally think that the man who has no "restrictions" by knowing all the laws of science will be the most likely to try something that defies those laws. the man that follows the law knows whats going to happen the man that dosen't will try something the law abiding scientist would call shenanigans on I'm not saying don't learn science, but I am saying sometimes ignoring laws can open the doors to success (excluding of course, Criminal law. thats just not a good idea)
good point, plus at one time people said it was impossible to fly, it couldn't be done. And now look at us.
lol, this reminds me of how my 6-year-old sister wouldn't believe me when i told her that someone's been on the moon :]
chaoscampbell (author)  chaoscampbell10 years ago
just to prevent any silly comments....... my use of man in this post is in referance to huMANs. wasn't being sexist
That's a very good point, I might still carry it out, if only to see *how* it fails.
Even better - you could do half an hour of research, and see how much electrical energy you can recover from a given mass of water at a given height (looks up some statistics on the best efficiency obtained by hydroelectric dams), and how much electrical energy it takes to pump water up to that height.

Actually, I'll do the honors, if you don't mind...

Top Google hits for "hydroelectric efficiency" indicate that "The
efficiency of today's hydroelectric plant is about 90 percent." That means that out of every 100 kWh of potential energy stored in the water, your waterwheel will only be able to extract at best 90kWh. The rest is lost due to friction, turbulence, etc.

Some power companies actually use something called "pumped storage", which is close to what you have in mind: during periods of low electricity consumption (i.e. at night) they will actually pump water *up* into the reservoir, which they can then use during peak consumption. That way they can run their other power plants (e.g. nuclear plants) continuously, despite fluctuating energy demands. Essentially, they use the water reservoir as a big energy storage device to even out the fluctuating demand.

Let's assume that the hydroelectric plant uses reversible turbines, so they can pump water back up into the reservoir at night with the same machinery they use to generate electricity during the day (i.e. simply reversing your "waterwheel"), and let's assume optimistically that you can do *that* with 90% efficiency as well. That means that if you spend 90kWh of electrical energy to run the pump, you will only be able to store 90 kWh worth of potential energy back into the water reservoir.

Now imagine running a waterwheel and a pump simultaneously... Suppose you have 367 tonnes of water stored at a height of 100 meters - that conveniently contains 100 kWh worth of potential energy. Running all this water past your water wheel will be able to extract 90 kWh worth of electrical energy from this. Running the pump using this 90 kWh worth of electrical energy will be able to pump up enough water to store 81 kWh worth of potential energy, or only 297 tonnes at 100 meters of height (or all 367 tonnes up to a height of 81 meters).

Here's some more info on hydroelectric power, if you want to learn more:

the systems used there have nothing to do with trying to make magic energy they are simply saving money by using cheap energy to refill the reservoir to sell as expensive energy during high demand times. Fiscally it's more than 100% efficient because the difference in price is enough to sell the cheap energy used to pump it up as expensive energy despite having used more energy to pump it up, It's not using the same energy to do it...
You just pee'd all over a 16 year old's 30 minute pipe dream :'-(
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