I'm working with a factory which has a backup generator which is used during grid instabilities or whenever the factory must disconnect from the grid for maintenance. In these cases, the generator is used instead to maintain operations.
However, I'm investigating whether there's another opportunity in using the generator's excess capacity to sell power on the grid.
I'll advance now that this question is not concerned with energy-market regulatory or financial viability issues for this idea (I've simplified the context here). The question is whether this is technically feasible.
The generator would then need to power two separate networks (the factory and the regional network), as seen below.
I had to create this with Powerpoint due to do the particular setup for the generator, which needs to feed into the two circuits without connecting them with each other (otherwise that'd just be the grid powering the factory, when this is precisely in the case when that's not possible or desirable).
So, this is the first part of the question: is this even possible? Can a source power two circuits while keeping them isolated from each other?
Assuming it is possible, we then get to the second part of the question. The generator's primary objective is powering the factory. Whatever is done on the grid is secondary. So the power must satisfy the factory and -- if there's excess capacity on the generator -- then feed into the grid.
Now, my thinking is that the factory has certain power needs (let's assume 1 MW). The generator (let's assume it can generate 1.5 MW) can run at 2/3 capacity and satisfy those needs. However, if the generator is also connected to the grid and is ramped up to generate it's maximum of 1.5 MW, where will those new electrons go? The resistance of the grid will be effectively infinite (when compared to the factory or the generator), so the natural route would seem to be factory. Which would mean the generator fries the factory's circuit and feeds almost nothing to the grid.
So, is it possible to design a circuit or device (including PIDs, microcontrollers, whatever) such that as much power as needed goes to one circuit, and the excess goes to another?