We've been working on this, actually, as an alternative energy source, starting way back with Johnson &amp; Johnson, to run an iBOT, because the best batteries you could get -- 10 watt-hours per kilogram in lead, 20 watt-hours per kilogram nickel-cadmium, 40 watt-hours per kilogram in nickel-metal hydride, 60 watt-hours per kilogram in lithium, 8,750 watt-hours of energy in every kilogram of propane or gasoline -- which is why nobody drives electric cars.