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How can the natural gas network be made greener ?

By ENGIE - 16 December 2019 - 17:38

The GRHYD demonstration project tests the injection of hydrogen produced from renewable electricity into the natural gas distribution network and the production of hythane® (a blend of hydrogen and natural gas) for NGV buses operating in the Dunkirk Urban Community.


Key numbers

Client challenges


  • Demonstrate, using real-life operating conditions, the technical, economic, environmental and social advantages of this new type of energy
  • Reduced greenhouse gas emissions
  • Integration of a 32% share of renewable energies in final energy consumption by 2030
  • Anticipation of the roll-out of hydrogen-fuelled vehicles
  • Leveraging of the region's industrial expertise and natural resources
  • Support for local economic development


ENGIE’s solution


The GRHYD* project, coordinated by ENGIE in collaboration with a number of new partners, applies the Power-to-Gas concept used to transform surplus renewable electricity into hydrogen through water electrolysis. Once converted, this energy can be stored, transported and used in the natural gas networks. And it has enormous potential: ADEME puts the potential for hydrogen produced from electricity via Power-to-Gas in France by 2035 at around 30 TWh per year.


The GRHYD project is one of the biggest hydrogen and Power-to-Gas initiatives in France. It tests the injection of hydrogen into the natural gas distribution network of Cappelle-la-Grande, a pilot city in the Dunkirk Urban Community, in order to meet residents' heating, hot water and cooking requirements using a greener form of energy.


Initially, the first hydrogen molecules injected into the local natural gas distribution network accounted for 6% of the total. This was then increased to 10%, and is now at its maximum level of 20%, supplying 100 homes and the heating system of a clinic in Cappelle-la-Grande’s “Le Petit Village” district.


A three-container assembly covers the electrolysis, storage and network injection phases, respectively. An NGV bus station will also be adapted for use with the hydrogen-natural gas blend, with hydrogen accounting for 6% initially, and then ultimately 20%. In total, a fleet of around 50 buses will run on this hydrogen-natural gas blend.


The GRHYD project is a perfect example of the Hydrogen Plan launched on 1 June 2018 by the French government, helping to “determine the acceptable technical and economic conditions for injecting hydrogen into the networks" through real-life data that it can be used to harvest.


Expertise and offers


  • Technological innovation
  • Processing of the electrolysis, storage and network injection phases
  • New way for using and storing renewable energies
  • Sustainable city and green mobility


“With this GRHYD project, we have a demonstrator which shows that it is possible to produce renewable energy that can be stored and then redistributed".

Philippe Vasseur, former president of the Chamber of Commerce and Industry for the North of France, former Minister