It seems obvious that future power is going to have to come from some other source than burning gas. My guess is nanobatteries. These advanced fuel cells will revolutionize the energy industry.
There are already applications in the military to power individual combat suits. You can bet that DARPA and the DOD have been long aware of the potential of these miniature power systems, and it seems like their commercial production has recently become more viable.
Nuclear Nanobatteries
Scientists at Sandia National Laboratories are developing a battery powered by a radionuclide source, which offers energy densities 3 to 5 orders of magnitude greater than chemical batteries.
See the article at sandia.gov
(wiki) Nuclear battery
Here is an excellent article about the commercialization of nanobatteries on Small Times News page.
Battery Power Online - http://www.batterypoweronline.com/
A nice article from Wired Magazine on the future of batteries: http://www.wired.com/wired/archive/14.11/battery.html
MIT's Laboratory for Electromagnetic and Electrical Systems has designed a revolutionary ultracapacitor. lees.mit.edu
Sandia National Laboratories is designing a nanobattery that will be used to power implantable devices, like the artificial retina developed by the Doheny Eye Institute at the University of Southern California.
Some nanobatteries are miniature fuel cells.
You can learn more about fuel cells at the Department of Energy's Fuel Cell R&D page.
Urine Battery
Physicists in Singapore have created a battery that is powered entirely by urine. Click here to view the 5-page research report. http://www.iop.org/ (PDF, 878k)
U.S. Patent 6,586,133 was awarded to Professor Dale Teeters and two of his chemical engineering students at the University of Tulsa. Click here to read the univesity article.
Solicore
Solicore makes thin, flexible batteries for smart cards, RFID, and medical devices. Check them out at www.solicore.com
Also see: Nanofuture | Powerfuture | Fluoride Batteries