CNN has an interesting article talking about the slow progress that has been made in battery technology compared to digital technology over the same period. The batteries used today are essentially the same ones used in the 1950s. Best quote: "Had batteries advanced at the pace of the computer processor, `a double-A cell would contain more energy than a tactical nuke.' " There are also brief mentions of battery-replacing technology that we've covered before such as hydrogen micro-turbines and mini-fuel cells.