Vehicle cryofuel tanks for LNG and liquid hydrogen are currently multilayer vacuum superinsulated (MLVSI). MLVSI are known for thermal conductivities as low as 10(-6)W(mK)(-1) at cryogenic temperatures. Due to high system costs, these tanks burden the economy of cryofueled vehicles. In search of low tank costs, powdrous load-bearing insulations, applied to large storage and transport vessels today, were examined for their MLVSI-replacement potential. Thermal conductivities of some popular powders were measured to about 2-8 mW(mK)(-1) at zero and full external loads representing vacuum pressure enforced on the insulation layer. Furthermore, a transient simulation program was written to examine the influence of various operational parameters on powder insulated cryofuel tanks onboard passenger cars and trucks. The results were interpreted mainly for LNG fuel tanks with perspectives for liquid hydrogen.