In addition, Ru/Pr2O3 and Ru/Ba-Ca(NH2)2 save electricity for compression of the introduced gas due to their low pressure. On the other hand, the low pressure makes liquefaction and recovery difficult, and as shown in Table , very low temperatures are required. In other words, the advantage of reduced power costs due to lower pressure reaction conditions is offset by the power necessary for lower temperatures in the recovery process. It is the same conclusion as our previous report. 70