Byproducts
In the real world, manufacturing often ends up with various byproducts that companies can either sell or utilize for various other productions. In PrUn, this could be a simple way to give low tech companies more bang for their buck, and give high tech companies more opportunities to interact with local sources for resources they might need. Imagine the Food Processor ends up with 1 Carbon for every 50 Basic Rations they produce, or the Refinery dropping 1 PE every 200 SF or so on. Nothing game breaking, but when you’re heavily investing a base into a niche output it can be nice to get small returns that boost your income potential overtime.