Forefront HQ, portal room. Previously
"Not so much lightning, as an aspect of the fundamental force that also governs lightning", the engineer clarified. "To power the magnets, electricity is run through them, however. But changing this aspect wouldn't accomplish much, I don't think.
Least of all because this is only half of the process into opening a portal. A tear in space-time made like this will be small, much smaller than anyone could fit through. And unstable to boot. It would remain open for less than a second before collapsing in on itself."
Explaining this, the engineer paused. When he continued, he raised a hand with a finger extended, keeping this up for a few words into the sentence. "So, we need to make it bigger, and keep it open. To do this, we inject negative energy into the breach." The engineer then raised a closed fist, and cupped his other hand around it. "As the negative energy flows through the breach, it forces it open, and keep it that way, for as long as the supply is maintained", he continued to explain, moving the one hand away from the first, and opening it, pantomiming a hole getting wider. "And now we have a functional doorway into another world.
And here, we think, also lies our problem. This stream of energy would be coming out of the other end of the portal, and we think this is how the people on Earth track them. And since we can't make a proverbial door without first making a hole for the door frame, it's a bit of a pickle."
