"Under no scientific theory can you pluck energy from the vacuum." You can if you're very patient, have a lot of material, and lucky aim, thanks to the metric

"Under no scientific theory can you pluck energy from the vacuum." You can if you're very patient, have a lot of material, and lucky aim, thanks to the metric expansion of space. From within a galaxy cluster shoot one end a very very long wire into the central black hole of a galaxy in a distant galaxy to anchor the far parts of the wire, and wind some near part of the wire around the pole of an electrical generator in your galactic cluster. You won't get much power for a long time by human standards, but you'll get an awful lot of energy (and eventually substantial power give or take divergence in the stress-strain tangent modulus and related quantities) even after the gravitationally anchored far end has receded outside your generator's Hubble volume. Mining \Lambda dark energy for fun and profit, brought to you by $nabla_\mu T^{\mu\nu} = 0$, where $nabla_mu$ is the covariant derivative. It only takes a large up-front investment that you'll wish you had made billions of years ago.