You're skeptical- a good thing in general and especially in this case.
Zero-point energy is a natural consequence of quantum mechanics. Take a little mass on a spring. Its potential energy is lowest when the spring is exactly unstretched. But that means that the mass is at a particular place, and the uncertainty principle would then require that its momentum have an infinite spread, giving it infinite kinetic energy. The real lowest energy state has the mass spread out over a little region, with the potential and kinetic energies each a little above their lowest possible values, but with the total as low as possible. That minimum is called the zero-point energy. Many quantum systems are mathematically analogous to a mass on a spring and have similar zero-point energies.
It's misleading to say that large fluctuations 'are occurring' in that lowest state, although scientists often use sloppy phrases like that. The system is just sitting in a state, which happens not to have definite values of position and momentum. It's not true, however, to say that its position and momentum are changing in any way. That language comes from inconsistent attempts to force quantum facts into classical descriptions.
No valid theory predicts any way to extract such energy, which would require leaving things in a state with less energy than the state with least energy, by definition of 'zero-point.'
What Prigogine's 'self-organization' ideas have to do with this is beyond me, since they weren't even concerned with quantum mechanics. (His main ideas on quantum mechanics concerned the role of density matrices in time irreversibility- and these ideas are rarely mentioned by any serious students of that issue.) The only connection that comes to mind is that Prigogine wasn't above shoveling a bit of BS on occasion.
Actually, this isn't the whole story here. Zero-point fluctuations in the fields of known particles, particularly the photon, have measurable effects. And even a very tiny amount of energy can be extracted from this when done properly, but you can also think of it as extracting energy from reducing the potential energy associated with the configuration of actual pieces of matter. Here's how this works:
In 1948, Hendrik Casimir found that the zero-point fluctuations in the photon field of the vacuum are affected by nearby conducting bodies, which create a boundary condition on the electromagnetic field, forcing some components to be zero on the surfaces of the conductors. Classically, this means that standing waves in cavities can have wavelengths no more than twice the length of a cavity. The quantum fluctuations are in the standing-wave modes for a piece of vacuum bounded by conducting walls, and so long-wavelength quantum fluctuations (ones with lower energy) are not allowed, while high-frequency, short-wavelength fluctuations are still present. If you make the cavity small enough, or put two conducting plates close enough together, you can shut out an ever-increasing portion of the fluctuation spectrum, starting at the low end. The low-frequency oscillations still take place outside of the cavity, and so the energy density of the zero-point fluctuations inside the cavity is less than that outside. The sides of the cavity therefore feel an inward force (typically this is done with two parallel conducting plates) and the force per unit area is
F/A = pi^2*(hbar)*c/(240d^4)
where hbar is Planck's constant divided by 2pi, c is the speed of light, and d is the distance between the two plates. The force is very very very feeble except at very short distances (microns or nanometers). There are important corrections to this for real materials -- the calculation above assumes that the conducting plates are shiny at all frequencies. Real materials start becoming transparent to very high-frequency electromagnetic radiation, and for real materials the force is less. The apparently large value of 1/d^4 for small d gets cut off by the fact that the short frequencies aren't reflected well.
The force is so feeble it has taken a large amount of effort and technology even to measure it. Here's an article in Reports on Progress in Physics at this link
describing recent measurements of the force.
This is kinda cool, but it really isn't a very good source of energy. In particular, once you've brought your conducting plates together, that's it -- no more energy can be extracted from these plates until you pull them apart again. The force acts a like an weak attractive spring between two conducting plates; it can be overshadowed by other forces, like the electrostatic force if the plates aren't at exactly the same voltage, or perhaps even gravitational forces.
So there's a potential energy associated with the Casimir force between two conducting plates at a particular separation. You can add energy to the system by pulling the plates apart or get energy out by allowing them to pull together. But you cannot get free energy this way, for the same reason that you couldn't if the plates were held together with rubber bands.
(published on 10/22/2007)