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New energies 08/02/2021

A New Way To “Blend” Green Hydrogen Into Natural Gas Pipes

Green hydrogen has long been touted as one of the best solutions to decarbonize the world’s energy supply — but transportation problems have so far left its true potential untapped. 

A new Hydrogen Blending Demonstration Program in California is trying to solve all of these problems — by injecting hydrogen in existing natural gas pipes.

For starters, hydrogen has to be kept cold and pressurized, making it difficult to deliver. To be sure it is bonafide “green,” the hydrogen itself must be generated through renewable energy sources, which are intermittent by nature, creating a logistical nightmare for trucking, shipping and transportation companies. Finally, the lack of hydrogen pumps makes switching to hydrogen difficult for gas stations.

A new Hydrogen Blending Demonstration Program in California is trying to solve all of these problems — by injecting hydrogen in existing natural gas pipes. While similar trials have been run elsewhere in the world, the program, which was announced in late 2020 by SoCalGas and San Diego Gas and Electric, is believed to be among the first of its kind in the U.S. and should yield the first preliminary results in early 2021. Here’s the lowdown on how it works:

  • The project will use energy from renewable sources at times in which supply exceeds local demand. It will use the surplus energy to create green hydrogen, a zero-emission fuel. Then, the hydrogen will be blended into the natural gas grid at the point of production in small proportions. By using existing gas pipes, the program aims to show we can sidestep both trucking and financial barriers to transporting hydrogen.
  • The companies involved in the trial want to understand just how to incorporate hydrogen into the gas grid safely. In small proportions, hydrogen behaves almost identically to other compressed natural gasses it’s blended with — and only needs different treatment when it represents more than 30% of the blend. Initially, the companies will test a blend with 1 percent of hydrogen and gradually increase to 20% to study its behavior.
  • SoCalGas is also working with Dutch company HyET to solve the problems where hydrogen has to be taken out of the pipes and used by consumers: gas stations. The companies plan to trial HyET’s Electrochemical Hydrogen Purification and Compression technology, which can sift hydrogen out of the grid and compress it into a storage tank. The program starts small, attempting to compress about 10 kilograms of hydrogen per day and plans to work towards a daily goal of 100 kg. That would be enough to fill up about 20 cars, bringing us another step closer to making hydrogen cars — or trucks, or trains, or planes — commercially viable.


“Natural gas transportation and distribution networks are seen as essential alternatives to road transport of hydrogen. In this case, the hydrogen is injected into the network and then selectively picked up at a point of use. The injection rate depends on the nature of the network and can reach a volume of 20% as demonstrated in the GRHYD project coordinated by ENGIE Lab CRIGEN.

In general, transport networks can only handle hydrogen content of up to a few percent points. Getting high-purity hydrogen then becomes a challenge and developing highly selective technologies becomes essential. Electrochemical compression is a promising solution, since it could allow hydrogen to be separated and compressed simultaneously to pressures compatible with mobility. Nevertheless, developments must continue in order to achieve the expected technical and economic performance.” — Camel Makhloufi, research engineer with the Hydrogen Lab at ENGIE Lab CRIGEN.

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