The Spacial Variance Reactor works by drawing energy from the natural movement of verteron particles between subspace layers as they maintain the 2nd law of thermodynamics. As the surrounding energy level decreases, they increase the local entropy to maintain a balance between subspace layers. The reactor pulls verteron particles through a series of accelerator coils as they emerge from subspace, which in turn causes more such particles to pull between the subspace barriers. The particles themselves are of low energy, the primary energy is gained from the intense disturbance in the subspace barriers which occurs when significant particle flow is drawn from nearby layers of subspace.
Size Restrictions
Thus far the size of the reactor is limited, as the reactor size increases it is more and more difficult to pull enough particle flow through subspace to generate power. It is far more effective to have a very small drawing particles from subspace and then amplifying the energy output or storing it for later use.
Clustering
It is also not possible to cluster reactors close together as the subspace layers become disturbed and may form a full micro-rift in space-time if reactors operate too close together (usually a range of about 35-38 mm or so).
Power
The power supplied can be substantial as the reactor's accelerator coils increase energy output exponentially. The only restriction is that if the subspace layers become too disrupted by the particle flow they can become unstable and power output is then absorbed back into the adjacent layers while the system tries to find equilibrium. This makes the reactor of limited usefulness, capable of creating bursts of very high power output that quickly falls off to a lower energy level in a very small space.