By Energy Worth Online
Black holes are generally portrayed as cosmic monsters that swallow everything that ventures too close, including light. But one of the strangest ideas in modern physics turns that picture on its head: under certain conditions, a black hole may not only consume energy — it could also give some of its energy back.
Scientists have long studied theoretical mechanisms through which energy can be extracted from a rotating black hole, potentially making these mysterious objects some of the most extraordinary energy sources imaginable.
The idea dates back to physicist Roger Penrose, who proposed in 1969 that energy could theoretically be extracted from a spinning black hole through a process now known as the Penrose process. The concept relies on a peculiar region surrounding a rotating black hole called the ergosphere.
The strange region outside the black hole
A black hole has an event horizon — the boundary beyond which escape is impossible. But a rotating black hole has another important feature outside this boundary.
The ergosphere is a region where the black hole's rotation causes spacetime itself to be dragged around. Anything entering this region is effectively forced to participate in the black hole's rotation.
This unusual environment creates the possibility of extracting some of the black hole's rotational energy without crossing the event horizon.
Penrose imagined sending an object into the ergosphere and splitting it into two parts. One part would fall into the black hole while the other escaped. Under the right conditions, the escaping part could carry away more energy than the original object possessed. The extra energy would come from the black hole's rotation, causing the black hole to lose some of its rotational energy. In simple terms, the black hole would effectively be acting like a gigantic cosmic flywheel.
But how can energy come out of a black hole?
This does not violate the laws of physics. The important distinction is that scientists are not proposing that matter or electricity is pulled out from inside the event horizon. Instead, the process extracts rotational energy stored in the black hole itself.
A rotating black hole possesses enormous angular momentum. If some of that rotational energy can be transferred to matter, electromagnetic fields or radiation outside the event horizon, energy can escape into the surrounding universe.
Researchers have developed another important theoretical mechanism known as the Blandford–Znajek process. In this scenario, powerful magnetic fields surrounding a rotating black hole can interact with its rotation and extract rotational energy electromagnetically. The mechanism has been extensively studied as a possible explanation for the enormous relativistic jets observed emerging from regions around some black holes.
A cosmic power plant?
This is where the idea becomes particularly astonishing. Some theoretical and numerical studies suggest that black-hole rotational energy extraction can be extraordinarily efficient. One influential study found that, under certain magnetically arrested accretion-flow conditions, energy-extraction efficiencies could reach roughly 300 per cent relative to the energy supplied by the accreting matter.
That does not mean scientists have discovered a machine capable of producing 300 per cent energy from nothing. Rather, the additional energy comes from the black hole's own rotational energy.
The process therefore resembles withdrawing energy from a spinning flywheel: the energy output can exceed the energy being supplied to the immediate system because another reservoir — the black hole's rotation — is being depleted.
Nature may already be doing it
Perhaps the most fascinating part is that this may not be merely a mathematical curiosity.
Astronomers observe powerful jets of particles and electromagnetic radiation associated with some black holes. The Blandford–Znajek mechanism has been proposed as one way in which rotational energy from black holes could help power such jets.
Scientists are still investigating exactly how these extreme cosmic engines work, and competing models suggest that some observed jets may instead draw much of their energy from the surrounding accretion disc.
Recent research shows that the subject remains active. In February 2026, researchers examined possible observational signatures of the Penrose process involving magnetic reconnection in a black-hole ergosphere. Another Physical Review D paper accepted in July 2026 investigated energy extraction from a magnetised charged black hole.
Could humans ever use it?
For now, the answer is no. Humanity has neither the technology nor the ability to travel anywhere near a black hole, much less construct an energy-harvesting system around one. The radiation, gravitational forces and extreme environment would make such an undertaking extraordinarily dangerous.
Therefore, the idea should not be confused with a practical renewable-energy technology.
Yet it remains one of the strangest possibilities in energy science: a black hole, famous for swallowing everything around it, could theoretically have its own rotational energy tapped and converted into outward-flowing energy.
The universe may already contain power plants far more extreme than anything humanity has built — and they may be hiding behind some of the darkest objects in existence.
The piece is based on established theoretical physics, while clearly distinguishing theoretical energy extraction from an actual deployable energy technology.
