You're referring to a possible Dyson sphere around Tabbi's star. Scary stuff if it is. Any civilization that can build on that scale could wipe us out on a whim. I don't buy the notion that an advanced race would be benevolent. Neither does Steven Hawking. Just look at human history and what happened when a primitive society was introduced to an advanced one. See how that worked out for native Americans.
Are you talking about a wormhole? Creating it and keeping it stabilized would require a massive amount of energy. A star would be a great source, although it wouldn't be enough. It requires more energy than the sun will put out during its entire lifetime. One question: How do they determine where they'll end up if they go into the hole? That's the bigger issue.