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Moving toward the deployment of CO2-free hydrogen chain

Hydrogen produced using a method that substantially reduces CO2 emissions is referred to as CO2-free hydrogen. Like other renewable energies such as solar and wind power, CO2-free hydrogen is an energy source which contributes significantly to CO2 emissions reduction and has therefore attracted attention as a technology which can contribute to long-term global warming countermeasure.
 Tokyo Gas is broadly examining technologies that can contribute to efficient and large-scale production, transportation, storage and usage of CO2-free hydrogen, and looking into the picture of hydrogen society in future.
 

Objective


The significance of environmental issues as societal issues continues to grow, and it is becoming increasingly essential that CO2 emissions be reduced. Hydrogen is attracting much attention as a means to contribute to long-term global warming countermeasure. CO2-free hydrogen has the advantage of emitting no CO2 during production. As CO2-free energy, renewable energy can be mentioned, and hydrogen can help address renewable energy's long-distance transport and power fluctuation issues.
Tokyo Gas is conducting a broad technical examination of the various methods being considered at each stage of CO2-free hydrogen production and hydrogen transportation, storage and utilization. In this way, Tokyo Gas is looking for optimal energy supply systems for its customers.
 

Production methods for CO2-free hydrogen


The two principal production methods for CO2-free hydrogen are outlined below

 

  1. Hydrogen production based on fossil fuels and CO2 underground storage
Water is electrolyzed using electricity generated from renewable energy sources such as solar and wind power, of which there is an abundance overseas or even a surplus in Japan, thus resulting in CO2-free hydrogen.
 
Hydrogen production based on renewable energy
 
  1. Hydrogen production based on fossil fuels and CO2 underground storage
    Hydrogen is produced from low-cost fossil fuels such as natural gas and coal, and the CO2 released as part of this process is separated and collected, and stored underground using Carbon Capture and Storage (CCS) technology, thus resulting in CO2-free hydrogen.
 
Hydrogen production from fossil fuel with the utilization of CCS technology

 

Transportation and storage methods for hydrogen


In its regular form, hydrogen is a gas with an extremely low energy density. For this reason, ways of converting hydrogen into various energy carriers which could be efficiently transported and stored are being studied.
 
  1.  Liquefied hydrogen
This refers to hydrogen cooled at -253ºC and turned into a liquid state for the purpose of transportation and storage.
  1. Methylcyclohexane (MCH)
Hydrogen is converted into methylcyclohexane by binding it to toluene for the purpose of transportation and storage. Before usage, hydrogen and toluene are separated again into individual components.
  1. Ammonia (NH3)
Hydrogen is synthesized with nitrogen (N2) in the air to produce ammonia for the purpose of transportation and storage.
  1. Synthetic methane
CO2-free hydrogen is synthesized with recovered CO2 to produce methane for the purpose of transportation and storage. 
 

Hydrogen utilization


Various methods are being studied for utilizing hydrogen in thermal power generation, fuel cell power generation and powering fuel cell vehicles (FCV); for utilizing ammonia as a direct fuel for thermal power generation and commercial burners; and for utilizing synthetic methane in city gas pipelines.
 

Research and development toward achievement of low cost and high efficiency CCS


Carbon capture and storage (CCS) refers to technology for separating out and capturing the carbon dioxide found in exhaust gas, such as that produced by thermal power plants, and then storing it underground. It is hoped that CCS technologies will become widely adopted, as it contributes to long-term global warming countermeasure by significantly reducing CO2 emissions. It is also a technology that is required when producing CO2-free hydrogen from fossil fuels such as natural gas and coal.
In order to enable efficient, low-cost CCS, Tokyo Gas is partnering with the Research Institute of Innovative Technology for the Earth (RITE) to research technology that converts CO2 into microbubbles which  allows larger amounts of CO2 to be stored underground. This technology makes it possible to efficiently store large amounts of CO2 into a limited space of geological layers, resulting in reducing CCS costs.
 
Achievement of a large amount CO2 storage at low cost Filter for the generation of CO2 microbubbles
  Filter for the generation of CO2 microbubbles
 

 Outlook of a CO2-free hydrogen supply chain


Tokyo gas is taking a broad look at technologies covering the entire supply chain (CO2-free hydrogen supply chain) for large-scale and efficient production of CO2-free hydrogen and hydrogen transportation, storage and usage, while looking into the picture of hydrogen society in future.
 
Moving toward the deployment of a CO2-free hydrogen supply chain

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