Obstacles include a restricted vehicle range, due to an on-board fuel storage system that is currently much larger and heavier than a gasoline tank, and a limited distribution and refueling network.

• 其中的障碍包括由机载的燃料储存系统一般比油箱体积要大并且重很多而导致行驶里程受限；以及有限的燃料分配和燃料补给网络.