Here is an interesting interview with a scientist/engineer working on the possibilities of using nanomachining to build Casimir Force generators.
http://www.crnano.org/interview.tymes.htm
The claim here is about using arrays of nanostructured Casimir force generators that harness "Casimir torque" energy.
From the interview:
" Question 10: How great is the potential for generating energy from the Casimir effect? Could machines based on Casimir torque obviate the need for fossil fuels or nuclear energy?
If it works, yes. The usage model would be much like solar energy, except not affected by weather or day/night or needing to be outdoors. (For the record, most of my home's power needs are provided by solar power - and that's only "most" because I have a lot of computer servers, and thus use enough power to qualify for industrial rates. Or rather, I did before the panels were installed. Suffice it to say that they've already paid for themselves, and it's been less than 5 years since installation.)"