|MadSci Network: Physics|
Here is an excellent article discussing many of the zero-point energy claims.
Basically, you can get extremely small amounts of work via the Casimir Effect (two closely-spaced plates will feel an attractive force due to the zero-point field), but this is always a one-time-only event. If you want to get work out of the zero-point energy a second time, you need to pull the plates apart again, which costs just as much work as you got out of the device in the first place! So, unless current thinking about the zero- point-field is all wrong, no one will ever be able to make a useable device which extracts energy from the zero-point field.
The above article makes a very good point; if there's really as much zero- point-energy as a naive calculation would suggest, the universe should have collapsed in on itself a fraction of a second after the Big Bang. Given that we're still here, it's likely that the zero-point energy is *much* smaller than the free-energy proponents are claiming. I certainly support further research into this odd discrepancy between the large calculated zero point energy and the small observed value. But I don't think that pseduoscientists jabbering about "free energy" should be given public funding without a well-documented, published, and peer-reviewed basis for their claims.
Now, outside of "free energy", there may indeed be many undiscovered consequences of the zero point field. If you have run across papers discussing new manifestations of the zero-point field under certain conditions, you may be looking at valid scientific work. But there is no accepted way to get any useful "free energy" from the zero point field.
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