I have read that Black holes could be the most efficient generators in the universe , is that what this study is getting at:

http://scitation.aip.org/getabs/servlet/...&type=ALERT

Here's the free paper:
http://lanl.arxiv.org/abs/gr-qc/0511131

Lots of interesting comments here:
http://arstechnica.com/journals/science.ars/2006/8/4/4887

Erich J. Knight