There is currently a glitch in the game which allows you to get Unlimited Power Nodes.
At Chapter 14, after the Zero-G area, save your game, exit and reoload it, then follow the instructions below - check the video out too to see how it's done.
Now, make your way back to the secured storage room earlier and you'll find replenished power nodes. (If you see credits only, just restart the checkpoint and try again.) Now head back to save your game again and reload the saved file and do it again. Sometimes you'll get one or two power nodes. If you're lucky, you'll find two nodes and a Ruby Semi-conductor.Click here to view the video