One of the myriad issues with hydrogen as a clean energy source is infrastructure, as it's very expensive to move around and store an extremely explosive gas. Toyota and its subsidiary Woven Planet believe they may have a solution with a new portable hydrogen cartridge prototype. The idea is that they can be filled up at a dedicated facility, transported where needed, then returned when you receive your next shipment. The cartridges would be relatively small at 16 inches long, 7 inches in diameter and about 11 pounds in weight. Toyota calls them "portable, affordable, and convenient energy that makes...