Concern for potential global climate change will become greater within the next decade, forcing society to move toward energies that will minimize the emission of greenhouse gases. Hydrogen energy is considered to present a potential effective option for minimizing the release of greenhouse gases. The Japanese Government promoted the WE-NET (World Energy Network) Project (Phase I: 1993-1998, Phase II: 1999-2002), which envisions: (1) construction of a global energy network for the effective supply, transport, storage and utilization of renewable energies and (2) promotion of hydrogen energy entry into the market in the near and /or mid- future, even before the construction of a WE-NET system. In this paper, the results of the Phase I research and development are summarized and the Phase II program is described, placing an emphasis on the research and development of small-scale and distributed hydrogen utilization technologies such as fuel-cell vehicle related technologies.
The Japan hydrogen project, WE-NET (World Energy Network), has shown that high-density LH2 (liquid hydrogen) is the most promising medium for transporting and storing large-mass hydrogen efficiently and economically. In the future, large-mass liquid hydrogen storage technology for ground tanks and ocean tankers will be needed, and the commercial scale may be the same as existing LNG storage systems, which have a storage capacity of several hundreds of thousands of cubic meters. The conceptual designs of 200,000 m3 LH2 tankers and 50,000 m3 LH2 ground tanks were studied in WE-NET Phase I (1993-1998). This study has concluded that the optimized thermal insulation structure for a large storage tank should be developed. Therefore, in Phase II of WE-NET (1999-2002), we tested the thermal conductance and cryogenic compressive strengths of insulation materials in order to develop various insulation structures. Their conceptual designs were reviewed by analyzing experimental results. To realize the government target of introducing 50,000 fuel-cell vehicles by 2010 and 5 million vehicles by 2020, a hydrogen supply infrastructure must be constructed. Since LH2 is applicable for the hydrogen infrastructure, we have developed a high-performance LH2 container, a key component of the system. This paper describes the conceptual designs of LH2 tankers and LH2 ground tanks, elementary tests of various insulations, and also the LH2 infrastructure for fuel-cell vehicles.