Wouldn't it be great if we could get "free energy"? I put "free energy" in quotes to indicate that it doesn't simply mean energy which is free, which
I guess you could claim solar power is once you have your solar collectors. I'm talking about the "energy from the vacuum" and similar claims.
I have read some of the threads about that topic on ATS. While I don't rule out the possibility completely, it seems pretty unlikely that if vacuum
energy is the lowest possible energy state of a system, that we can extract energy by making it go below its lowest possible energy state, because if
we could do that, then we could reasonably claim that it wasn't at its lowest possible energy state to begin with.
But I started wondering what the math would look like if we could extract energy from the vacuum, and I haven't seen anyone else do the math I wanted
to see, so I decided to do the math and thought I'd share it with you here.
How much energy is in the vacuum? We aren't 100% sure but recent measurements by the Wilkinson
Microwave Anisotropy Probe and many other experiments seem to be converging on a positive cosmological constant, equal to roughly 7 × 10^-27
kilograms per cubic meter. This corresponds to a positive energy density of about 6 × 10^-10 joules per cubic meter.
So the question I wanted to answer, is, if the vacuum energy COULD be extracted, how much "space" with this "vacuum energy" in it would I need to
power my home's electrical needs? The average home uses an average of 1020 watts of electrical
.(I picked the middle of the three figures). I use slightly less than that but it's close enough for me and probably more relevant to
everyone else if I just use the average.
Watts are joules per second, so this means if your home is typical, it uses 1020 joules per second.
1020 J/s divided by 6x10^-10 J/m^3 equals about 1.7 trillion cubic meters per second.
An olympic sized swimming pool has a volume of about 2500 cubic meters.
So, 1.7 trillion cubic meters per second divided by 2500 cubic meters equals 680 million olympic pool volumes per second.
There are 84,400 seconds per day, so you'd need 680,000,000 x 84,400 olympic pool volumes per day to power your home with that amount of vacuum energy
if the energy was even extractable, which it probably isn't.
So, you'd need to extract 100% of the vacuum energy from about 57.4 trillion olympic pool volumes per day to power the average home.
I don't know about you, but I can't even fit ONE olympic sized pool in my back yard, they are 50 meters or about 165 feet long by 25 meters or about
82 feet wide, and 2 meters deep. So even if we COULD extract this vacuum energy, where would you get the 57.4 trillion olympic sized pool volumes per
day needed to power your home? If you could only extract say 10% of the energy you'd need 574 trillion of those huge pools of space, every single
It just doesn't sound very practical to me even if we could extract energy from the vacuum, which I suspect we probably can't.
Now compare this with solar power for example. if you adjust the figures in this source
for the average power of 1020 watts, then you'd need 44 square meters of solar panels to power the average home. I believe the average home in the US
probably has that much space on the roof.
So even if you could extract the energy from the vacuum, wouldn't putting solar panels on your roof still be more practical? The solar panels are kind
of expensive now but I think the costs will come down in the future, and the efficiencies might go up too which means you might need less than 44
square meters of solar panels.
edit on 17-12-2011 by Arbitrageur because: clarification