# Is this a new and useful source of energy?

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1. Aug 6, 2015

### udtsith

Could you tap into the rotational energy of the earth by transporting water from the equator to the poles? For example, imagine a large "oil" type pipe that went from the equator to the arctic pole, perhaps located submerged in the pacific. Water would initially be pumped into it to generate momentum and overcome frictional force. As the water moved an energy gradient would be established between the water and the pipe. The water would still have the angular momentum from the equator but the pipe would not. So then perhaps along the way or at the end the water would be released to turn a turbine. So here is my estimate...the angular velocity at the equator is 445m/s, at the pole it would be (approx.) 0. So that means for 1kg of water you would get .5*1kg*450^2 of energy. That comes out to be 100,000 Joules. If the velocity is 450m/s that means that 450 cubic meters of water (450,000kg) would be outputted per second so...that would be 450K kg * 100,000 Joules would equal 3.9*10^6 kilowatt hours. The average north american home uses 10Kilowatt hours per year so...this would be enough to power 40 Million homes per year. Besides the cost of friction...this seems like a worthwhile endeavor...similar to building a 20KM high dam...it isn't free energy because you are taking it from the rotational energy of the earth. I think...

2. Aug 6, 2015

### tfr000

Er, ah... isn't your pipe moving with the Earth?

3. Aug 6, 2015

### davenn

that's out by a large factor. try around 11 MW ( 11,000 kiloWatts)

source ...
http://www.eia.gov/tools/faqs/faq.cfm?id=97&t=3

dave

4. Aug 6, 2015

### Staff: Mentor

If there were energy to be gained that way then the oceans would naturally flow from the equator to the poles. The flow would continue until the heat from friction had dissipated the energy gained by flowing, and then the oceans would settle at their minimum-energy level. That is, in fact, what determines sea-level.

5. Aug 6, 2015

### OmCheeto

Although flawed, it is an interesting question.
I never noticed before that the level difference, as measured from the center, is 21.3 km or 13.2 miles.
Here's an interesting analysis of what would happen to the oceans if the world slowly came to a stop:

If the Earth Stood Still
Modeling the absence of centrifugal force
By Witold Fraczek, Esri

Ouch! No more Canada, Europe, nor Russia.
On the up side though, everything left over looks pretty much connected.
We could built a railroad along the equator that circled the globe!

6. Aug 7, 2015