Hyzon managed to run its liquid hydrogen semi-truck for 870km during a 16-hour test run across Texas and called the fuel more economical than its gaseous counterpart. Liquid hydrogen is about two times more energy dense from a volumetric point of view than pressurized gaseous hydrogen (700 bar), but it requires a temperature below -253 Celsius in order to remain liquid, which adds significantly to the cost of any tank that could store it. Looking past the added complexity, due to thermal inefficiencies involved in the usage of any insulating material, there is a boil-off risk. Over a period of time the liquid absorbs some of the ambient temperature – we’re talking tiny amounts here – and it slowly boils…