1. Objective of R&DInternational Clean Energy Network Using Hydrogen Conversion (WE-NET) aims at contribution to solving global environmental problems by means of large-scale and effective utilization of clean and renewable energies such as hydraulic, solar, and wind which are available widely on the earth. Its purpose is also to establish technologies capable of introducing an international energy network utilized in wide fields such as hydrogen production from these energies, conversion of hydrogen as necessary, transportation, storage, generation of power, fuel for transportation, and town gas, in order to satisfy energy demands, and to develop core elementary technology as well as preparation conceptual design of the total system.Phase I of WE-NET scheduled for six years from FY 1993 aims at establishment of basic technologies for hydrogen production, hydrogen transportation and storage, and utilization of hydrogen, by means of necessary investigation, basic researches, and studies for elementary technologies, in order to obtain information necessary for the optimum design of the total system and establish technologies necessary for the design and construction of a pilot plant. In addition, studies for technologies adaptable to the project in future are intended to be carried out in parallel with the above to be properly reflected on every research and development items. The results obtained in R&D of Phase I will be reflected on realization of the plans of Phase II. Fig. 1 shows the schematic illustration of WE-NET. 2. Items and targets of R&DR&D for Phase I has been carried out in the following 9 subtasks.2.1 Subtask 1: Investigation and study for evaluating and reviewing R&DThe research plan for FY 1998, which ended March 1999, consists of an analysis of the current status of research and development activities on elemental technologies for the WE-NET system, total coordination of the whole project, total assessment of development results, and study on the plan of Phase II.2.2 Subtask 2: Review and investigation for promoting international cooperationIn FY 1998, we have examined and promoted the measures to obtain international understanding and cooperation for WE-NET project and examined and developed the measures to promote international exchange of technical information as well.2.3 Subtask 3: Conceptual design of the total systemIn regard to the conceptual design of the total system, followings were studied from various aspects as the items regarding a whole system which is independent of large scale and concentrated utilization by liquid hydrogen utilizing renewable energy, based on various suggestions to the interim evaluation of the WE-NET research and development which had been conducted in FY 1996 by Agency of Industrial Science and Technology and also from a view point of introduction and diffusion of hydrogen energy through the public as early as possible.
In regard to the national-level energy estimation and assessment, the target of the research in FY 1998 is to gain perspectives of hydrogen economy that take into account recent changes in energy circumstances such as the Kyoto Protocol signed at the COP3. The effects of external factors such as energy price, environmental constraints and performance of hydrogen utilization technologies on potential market penetration of hydrogen are examined through simulation studies with the MARKAL as well as a role of transitional secondary energy like methanol. In regard to the city-level estimation and assessment, this phase of the project completes the analytical work carried out in previous years of the research and finalises the comparison carried out between London and Tokyo. In regard to the safety measures and assessment, the following items and descriptions was identified as the agenda for FY 1998 (the last year of phase I). Investigation of safety technologies for dispersed use of hydrogen started from FY 1998.
2.4 Subtask 4: Development of hydrogen production technologyIn FY 1998, development efforts continuing from the previous year were directed at (i) elemental technology under the two hydrogen production techniques of electroless plating and hot pressing, and (ii) large cell stacking (electrode surface area: 2,500 cm2; 5 cells). Also, optimum criteria and conceptual design for a practical scale of hydrogen production as determined the previous year were re-examined, and the impact on hydrogen production cost studied. Under research on high-temperature resistant, solid polymer electrolytes, several types of new polymer electrolytes were synthesized and their properties evaluated.Also, the present status of the ion exchange membrane, essential under the subject hydrogen production method, as well as literature pertaining to water electrolysis were studied. 2.5 Subtask 5: Development of hydrogen transportation and storage technologiesIn regard to the large capacity hydrogen liquefaction facilities, goals of studies in the Phase I are that to make a conceptual design of large-scale liquefaction facilities. In regard to the liquid hydrogen transportation tanker, the research objectives in FY 1998 were to conduct the following work based on the achievements of the previous research:
In regard to the " liquid hydrogen storage facilities", the performance of the large-scale thermal insulation performance test apparatus, that had been fabricated in FY 1997, was checked. Compressive strength of the thermal insulating material at LH2 temperature was tested by using the relevant test apparatus fabricated under Subtask 6. In regard to the devices for common use, the improved magnetic bearing, in which a inducer is installed to prototype pump in order to improve pump suction characteristics was tested in series. Also a feedthrough for sensors was developed and tested in liquid hydrogen.
Following development targets are set for storage by hydrogen absorbing alloys. 2.6 Subtask 6: Development of cryogenic materials technologyAlthough the existing materials useable in the cryogenic range (20K) are available in certain cases at present, there is few data regarding toughness, fatigue, and serration of structural materials at the temperature range of liquid hydrogen. In addition, since structure materials used in the liquid hydrogen environment may contact gas hydrogen at room temperature, they must have the strong property against hydrogen embrittlement. On the other hand, materials useable in the liquid hydrogen range are hard to be welded, and problems of crack in welded parts are caused if welding is made. Therefore, structural materials useable in the liquid hydrogen condition and their proper welding methods are to be studied, by development of new materials as necessary as well obtaining of basic data for the existing materials. The requirements from materials are to be determined relating to the development of hydrogen transportation and storage describing in Subtask 5.2.7 Subtask 7: Feasibility study on utilization of hydrogen energyStudy and investigate about the demand of level and application technologies for hydrogen energy in the future by different mode of use (gaseous and liquid hydrogen etc.), make proposal for application technologies, clarify the advantage and disadvantage of each technology and identify development issues. Furthermore, develop element technologies, if needed, for each of the studied hydrogen utilization technologies.2.8 Subtask 8: Development of a hydrogen-combustion turbineThe high-pressure combustion tests are carried out for 3 types of combustors by means of the test facility in order to evaluate combustors and the measuring device. The basic performance of the combustors is understood, and as for the measuring device, its possibility of application and problem are examined. Furthermore, based on the test results, the performance of each type of combustor is assessed and the optimal type of combustor is selected for the hydrogen-combustion turbine.In consideration of research and development of a hydrogen combustion turbine, the basic technologies necessary for the development of turbine components are surveyed and studied, and elemental, research and development for main auxiliary equipment are conducted as well in order to establish the basic technology necessary for a pilot plant. Focusing on super alloys, ceramic and carbon/carbon composite materials which are expected to be applicable to the hydrogen combustion turbine, design and experimental production of these materials were conducted and then their basic properties were obtained. Also, some technical problems to be solved in future were found. 2.9 Subtask 9: Study of innovative and leading technologyWE-NET is a long-term project. Therefore, in promoting the project, there may be some certain innovative and leading technologies not included in present objects of R&D, although they are promising for the future. On the other hand, incorporation of existing technologies into WE-NET project may be necessary depending upon their technological improvements.Such innovative and leading technologies and existing technologies are to be studied, investigated, and evaluated, and depending on the situation further studies are to be conducted so that useful suggestions and proposals may be made as to the course for the WE-NET project to follow, as well as its R&D. The development schedule of R&D items mentioned above is shown in Table 1. 3. Summary of FY 1998 ResultsIn FY 1998, the R&D activities in each development field were focused on research of existing technologies. However, in some fields, the studies of the elementary technologies were commenced. Major results obtained will be summarized below.According to the project proceeding, subtask 3-2 "Study on a global network" and subtask 8-1 "Study for on optimum system for hydrogen-combustion turbine" were finished in FY 1996 because the aiming results were obtained. 3.1 Subtask 1: Investigation and study for evaluating and reviewing R&DEvaluation was made for the total WE-NET project, and in the meantime overall coordination among each task and the review of the total plan were started in view of the Phase II of the project.3.2 Subtask 2: Review and investigation for promoting international cooperationWe distributed the English version of the 1997 Annual Summary Report on results and outcomes prepared by the NEDO to approximately 170 pertinent organizations overseas, who were listed as our regular partners for information exchange and made presentations of the WE-NET activities at the following international symposiums to develop understanding for the concept of the WE-NET project,
3.3 Subtask 3: Conceptual design of the total systemPower generating costs in the system with hydrogen combustion turbine were estimated, on the assumption that hydrogen could be produced by coal gasification and reforming of natural gas which is a typical hydrogen production method of reforming of fossil fuel and an extension of existing technologies to be able to secure huge amount of hydrogen.A general study was conducted on the economic efficiency of the hydrogen diesel system, fuel cell system, and automobile fuel supply system as a distributed utilization system of hydrogen from a view point of introduction and diffusion of hydrogen energy through the public as early as possible. Assumptions for the simulation study is revised as described in the following considering the Kyoto Protocol signed at the Third Conference of Parties of Framework Convention for Climate Change (COP3) and subsequent changes in energy circumstances: 3.4 Subtask 4: Development of hydrogen production technologyDuring this fiscal year, the present status of membrane technology was studied based on information obtained from membrane manufacturers. Specifically, data provided by four membrane manufacturing firms were used to summarize the membrane characteristics of each firm.The conceptual design and feasibility study of a 32,000 Nm3/h hydrogen production plant were carried out in the last year. Correspondingly, in FY 1998, the results were re-examined more accurately,and a sensitivity analysis was carried out to find the influence of factors on hydrogen production cost. Also, in order to assist a project pertaining to the verification of system performance of hydrogen fueling station, which is one of short-term programs of WE-NET Phase II, a 300 Nm3/h hydrogen production system (package type) was studied. In addition, the feasibility of the electrolyzer operation at high temperature (200°C) was examined in relation to the high temperature polymer electrolytes currently under development. 3.5 Subtask 5: Development of hydrogen transport and storage technologies(1) Development of large-capacity hydrogen liquefaction facilitiesBased on the final trade-off study in the last year, we have chosen a hydrogen Claude cycle as a liquefaction process. To conclude our study of the large hydrogen liquefaction plant in WE-NET phase I, we have conducted a conceptual study of the whole plant including important auxiliary equipment to make a visual image of the plant, and have started preliminary study of a large centrifugal type hydrogen compressor.
(2) Development of liquid hydrogen transportation tanker
(3) Development of liquid hydrogen storage facilities
(4) Development of devices of common use
(5) Development of hydrogen absorbing alloys for small-scale transportation and storage system 3.6 Subtask 6: Development of cryogenic materials technologyResearch and development activities mainly consisting of characteristic tests on candidate materials in liquid hydrogen were performed to accumulate data in the database on cryogenic materials. Further, taking in consideration the actual state of use of materials, studies were performed on the influences of plastic working on materials characteristics and that of hydrogen invasion activity into materials and also investigation of material quality was performed on the materials disassembled from a liquid hydrogen lorry tank.3.7 Subtask 7: Feasibility study on utilization of hydrogen energy(1) Investigation and study for power generationBasic characteristics such as combustion efficiency, indicated efficiency were determined, performing the combustion test wherein hydrogen is injected into argon-oxygen atmosphere and steam-oxygen atmosphere utilizing the rapid compression and expansion equipment installed in the Mechanical Engineering Laboratory of Agency of Industrial Science and Technology, aiming to proof actually for realizability of the two system, namely the hydrogen diesel engine cogeneration of argon circulation type and steam circulating type.
(2) Investigation and study for transportation means
(3) Investigation and study for fuel cell utilizing pure hydrogen
(4) Investigation and study for cryogenic energy application
(5) Investigation and study for hydrogen refueling station
3.8 Subtask 8: Development of a hydrogen-combustion turbine(1) Development of combustion technologyHigh-pressure combustion tests are performed by means of 3 types of combustors in the test facility for evaluation of combustors. As a result of the assessment, the annular type combustor with oxygen-diluting combustion method is selected as the optimal combustor for the hydrogen-combustion turbine. Furthermore, the applicability and problems of the device continuously measuring residual gas concentrations and of the gas temperature probe were found.
(2) Development of turbine blades, rotors and other major components
(3) Development of major auxiliary equipment
(4) Development of ultra-high temperature 3.9 Subtask 9: Study of innovative and leading technology6 proposals were collected in FY 1998. And 7 proposed technologies, including 1 proposal collected in the latter half of FY 1997, were evaluated to prioritize for feasibility study. Conceptual designs for 5 out of these 7 proposals were carried out.4. Future developmentResearch, basic investigation, study of elementary technologies, and other investigations will be carried out continuously to FY 1998 to obtain necessary information for the optimum design of the total system, in order to confirm establishment of technologies required to design and construct a pilot plant.
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