Introduction: A Telecom Giant's Vision for the Hydrogen Society
Japan's telecommunications giant NTT Group is advancing an ambitious plan to repurpose its nationwide underground communication infrastructure for hydrogen transportation. The project aims to utilize underground conduits that have seen declining usage rates due to the proliferation of fiber optic cables, transforming them into a network for transporting hydrogen—a next-generation clean energy source.
As Japan works toward achieving carbon neutrality by 2050, hydrogen is expected to play a crucial role. However, one of the biggest challenges in hydrogen adoption is establishing transportation infrastructure. NTT's concept represents a groundbreaking approach to solving this challenge through the creative utilization of existing assets.
NTT's Massive Underground Infrastructure Network
NTT Group possesses an extensive communication infrastructure built up since the days of the Nippon Telegraph and Telephone Public Corporation. The scale is remarkable:
Key Infrastructure Assets:
- Underground conduits (pipelines): Approximately 600,000 km
- Tōdō (tunnel-type passages): Approximately 650 km
- NTT communication buildings: About 7,000 locations nationwide
The underground conduits—pipes designed to house communication cables—stretch a total distance equivalent to circling the Earth roughly 15 times. The tōdō are larger tunnel-type facilities where people can walk through, with approximately 290 km running beneath Tokyo alone.
Previously, metal cables (copper wires) were the primary medium for telecommunications, but today, thin fiber optic cables have become standard. Since more lines can now be accommodated in conduits of the same diameter, utilization rates have dropped to around 40%. NTT's concept leverages this "empty space" for hydrogen transportation.
Double-Pipe Technology for Safety
The core of NTT Anode Energy's hydrogen transportation technology development is the "double-pipe method." This approach transports hydrogen using a dual structure consisting of an inner pipe for hydrogen transport and the existing communication conduit as the outer pipe.
Benefits of the Double-Pipe Method:
- Significant cost reduction by utilizing existing conduits
- Reduced risk of damage to hydrogen transport pipes
- Direct detection capability within the hollow layer if hydrogen leaks from the inner pipe
- Potential elimination of "odorization" typically required in conventional gas transportation
Particularly noteworthy is the leak detection system utilizing optical fiber sensing technology. A "composite detection technology" has been developed that leverages the explosion-proof properties and distributed sensing capabilities of optical fibers to immediately detect and respond to hydrogen leaks.
Joint Demonstration with Tokyo Metropolitan Government and AIST
From July 2024 to March 2025, NTT Anode Energy conducted demonstration experiments in the underground common duct of the Tokyo waterfront subcenter area, in collaboration with the Tokyo Metropolitan Government Port Bureau and the National Institute of Advanced Industrial Science and Technology (AIST).
For safety considerations, helium—which has leakage behavior nearly identical to hydrogen—was used for the following verifications:
- Construction feasibility verification - Confirming installation and connection workability in common ducts
- Leaked gas diffusion behavior verification - Understanding diffusion processes during leakage at closures (connection points)
- Air purge verification - Measuring the effectiveness of diluting leaked gas with compressed air
- Advanced optical fiber sensing verification - Confirming leak detection technology through acoustic vibration detection
Hydrogen Supply Chain Demonstration at Osaka-Kansai Expo 2025
At the Osaka-Kansai Expo 2025, NTT Anode Energy and Panasonic are jointly implementing a "hydrogen supply chain model."
Electricity generated by perovskite solar cells on the NTT Pavilion roof is used to produce green hydrogen through a water electrolysis unit. This hydrogen is stored in metal hydride tanks and supplied to the Panasonic Group Pavilion through approximately 200 meters of underground pipeline. On the Panasonic side, electricity is generated using a pure hydrogen fuel cell and used for nighttime LED lighting.
NTT Anode Energy aims to commercialize this hydrogen supply chain model by 2028.
Cost Reduction Effects and Expected Economic Viability
If NTT's concept is realized, significant cost reductions in hydrogen infrastructure development can be expected.
Reduction Effects Compared to Building New Pipelines:
- Initial costs: Can be reduced to 50% or less
- Construction period: Significant shortening possible
Current common hydrogen transportation methods—high-pressure hydrogen cardlers and tube trailers transported by truck—have limited capacity per vehicle and are not suitable for mass transportation. While liquid hydrogen tankers have higher transportation efficiency, they face challenges with high plant construction and operation costs.
Pipeline-based hydrogen transportation is considered the most economical method for short-distance, high-volume transport. NTT's utilization of existing infrastructure has the potential to accelerate this realization.
Domestic and International Collaborative Projects
NTT's hydrogen pipeline concept is linked to several major projects.
Tokyo Airport Waterfront Area Project (Agreement signed September 2024): Based on an agreement with the Tokyo Metropolitan Government Bureau of Industrial and Labor Affairs, business viability analysis and roadmap development for the hydrogen supply chain are being conducted for 2030 and 2050. Individual studies are being carried out for each phase: "producing," "transporting," and "using."
Himeji Area-Origin Project (Adopted June 2024): A collaborative hydrogen transportation and utilization survey involving six companies: Kansai Electric Power, JR West, JR Freight, Panasonic, and NTT Group. The project promotes technological development of hydrogen transportation methods utilizing existing infrastructure such as railways and communication conduits.
Position in Japan's Hydrogen Strategy
Japan formulated the world's first "Basic Hydrogen Strategy" in 2012, which was revised in 2023. A supply chain investment plan of 15 trillion yen over 15 years, combining public and private sectors, is under consideration. Hydrogen introduction targets are set as follows:
- 2030: 3 million tons
- 2040: 12 million tons
- 2050: 20 million tons
In the power sector specifically, the aim is to supply 10% of all power sources with hydrogen and ammonia by 2050. NTT's initiatives could become a crucial infrastructure foundation supporting this national strategy.
Comparison with Global Trends
Hydrogen pipeline development has become a global trend. Germany, in particular, is advancing a plan to build a 9,040 km hydrogen pipeline network by 2032, at a cost of approximately €20 billion. About 60% will be converted from existing natural gas pipelines, with 40% being newly constructed. The first 525 km began operation in 2025.
Across Europe, under the European Hydrogen Backbone (EHB) initiative, a goal has been set to develop or convert more than 31,000 km of pipelines by 2030.
What makes NTT's concept unique is that it utilizes "communication conduits"—completely different infrastructure from gas pipelines. This represents an advanced approach that is unprecedented worldwide.
Challenges and Future Prospects
Several challenges remain for the practical implementation of hydrogen pipelines.
Technical Challenges:
- Addressing leakage risks, as hydrogen is the smallest molecule
- Countermeasures against hydrogen embrittlement (phenomenon where metal materials become brittle due to hydrogen)
- Ensuring airtightness and safety assurance in case of leakage
Regulatory Challenges:
- Compliance with the Gas Business Act and other regulations
- Development of new safety standards and technical criteria
- Accumulation of scientific evidence necessary for legal framework development
Business Viability Challenges:
- Creating and expanding hydrogen demand
- Setting appropriate hydrogen selling prices
- Building collaboration systems with consumers
NTT Anode Energy aims to overcome these challenges by leveraging expertise cultivated in the telecommunications business, including 24/7 operational monitoring systems, network surveillance technology developed since the public corporation era, and rapid response capabilities through personnel deployed nationwide.
Conclusion: From Communication Infrastructure to Hydrogen Infrastructure
NTT's hydrogen pipeline concept is an innovative initiative that discovers new value in underground communication facilities—often viewed as "legacy infrastructure"—and aims to contribute to Japan's decarbonization.
The vast network of 600,000 km of conduits, 7,000 communication buildings, and years of accumulated monitoring and maintenance know-how—by repurposing these assets for hydrogen transportation, there is potential to significantly accelerate the realization of a hydrogen society.
If this concept, targeting commercialization by 2028, succeeds, Japan will establish a model unprecedented in the world: hydrogen transportation utilizing communication infrastructure. This could serve not merely as an energy policy but also as a model case for other countries in terms of creative utilization of existing infrastructure.
What strategies are being considered in your country for utilizing infrastructure toward decarbonization? Are there any initiatives to convert existing facilities into new energy infrastructure? We'd love to hear about them!
References
- https://journal.ntt.co.jp/article/32102
- https://journal.ntt.co.jp/article/23106
- https://www.ntt-east.co.jp/release/detail/20240920_02.html
- https://www.nikkei.com/article/DGXZQOUC025UE0S5A001C2000000/
- https://group.ntt/jp/expo2025/green/
- https://www.mirait-one.com/miraiz/5g/column102.html
- https://globalenergymonitor.org/report/europe-gas-tracker-2025-hydrogen-edition/
- https://www.cleanenergywire.org/news/hydrogen-start-flow-pipelines-germany-2025
Reactions in Japan
NTT's hydrogen pipeline concept is an amazing idea. Utilizing 600,000km of existing infrastructure is truly an evolution of Japan's 'mottainai' spirit. It's far more cost-effective than new installations and shortens construction time. This is Japan's technological prowess at its best.
Hydrogen is the smallest molecule, so leakage risk is concerning. Communication conduits weren't designed for hydrogen transport, right? I want more verification data on whether the double-pipe method can ensure safety. The technical hurdles shouldn't be underestimated.
As a shareholder, I welcome NTT's entry into hydrogen as a new business beyond telecommunications. With concerns about slowing growth in the telecom sector, developing new revenue sources utilizing nationwide infrastructure is commendable. If 2028 commercialization happens, it could be a significant game-changer.
This initiative shows real commitment to decarbonization. I have high expectations for the Expo demonstration. But it's meaningless if the electricity used for hydrogen production isn't green. I hope they aim for carbon-free across the entire chain from production to transport to usage.
NTT conduits are spread throughout rural areas too, so if this is realized, it might help solve the shortage of hydrogen stations. However, creating hydrogen demand in rural areas is a challenge. Even if infrastructure is ready, it's meaningless without users...
Maintaining tōdō and conduits is really hard work. With hydrogen transport, safety management becomes even more critical. I'm worried about increased burden on field workers. Hopefully AI and remote monitoring can help, but there will still be many situations requiring human eyes and hands.
Germany plans to convert existing gas pipelines, but NTT takes a completely different approach with communication conduits. This is advanced even globally, and if successful, it could be exported as a new Japan-originated model. A noteworthy initiative.
Hydrogen has explosion risks if it leaks, right? An underground explosion could be catastrophic. They talk about leak detection with fiber optics, but will it really be in time? If they're doing this in urban underground areas, they need extremely rigorous safety standards.
When large companies develop this kind of infrastructure, it makes it easier for startups to launch new hydrogen-related businesses. Possibilities seem to expand for consumer-side solutions and more. I'm looking forward to it.
I want to see more detailed cost-benefit calculations. Less than 50% compared to new pipeline construction sounds attractive, but what about total costs including existing conduit renovation, safety measures, and operational costs? Won't it be unprofitable unless hydrogen prices drop?
I drive an FCV but hydrogen stations are too few and inconvenient. If this is realized, hydrogen infrastructure could expand rapidly, and FCVs might become more popular. Toyota and Honda would probably be happy about this, right?
Tokyo's underground already has various infrastructure intricately intertwined. Even if they're using existing conduits for hydrogen pipelines, coordination with other infrastructure seems challenging. Although tōdō are large enough for people to pass through, workspace is limited.
It's touching that the communication infrastructure built during the NTT Public Corporation era is being repurposed for hydrogen transport in the Reiwa era. The foresight in developing Japan's communication infrastructure is paying off in an unexpected way.
Regulatory hurdles like consistency with the Gas Business Act seem quite high. Developing new safety standards will also take time, so 2028 commercialization is an ambitious target. I hope they proceed with speed through public-private cooperation.
Detecting hydrogen leaks with optical fiber sensing is technically fascinating. It feels like a fusion of communication and energy technologies. I'd love to work in a field like this. Looking forward to Japan-originated innovation!
I don't really get this 'hydrogen society' talk, but if this is realized, will it affect electricity and gas bills? It would be nice if there are benefits for regular households too.
As factory decarbonization is required, if hydrogen can be supplied cheaply and stably, options will expand. I have expectations for NTT's concept. However, the key is how much hydrogen prices will drop. Currently, the price gap with fossil fuels is too large.
Is it okay to have underground hydrogen pipelines in earthquake-prone Japan? Isn't there a high risk of leaks or explosions during a major earthquake? I'm curious about the earthquake countermeasures.
In Germany, we're advancing plans to convert existing gas pipelines for hydrogen, but NTT's approach of utilizing communication conduits is very unique. Our plan is 60% conversion of existing pipelines and 40% new construction, but we never thought of using completely different infrastructure. I tip my hat to Japan's creativity.
Investment in hydrogen infrastructure is progressing in the UK as well, but it's interesting to see a telecom company like NTT entering the energy field. Creative utilization of existing infrastructure is a brilliant idea that enables both cost reduction and rapid deployment.
In the US, the enormous cost of building new hydrogen pipelines is a challenge. If we could repurpose existing infrastructure like NTT, deployment speed would significantly increase. However, safety verification needs to be done carefully.
France is participating in the European Hydrogen Backbone initiative, but utilizing communication infrastructure wasn't considered. This Japanese approach might be applicable in other countries too. I look forward to sharing of technical data.
South Korea is also pushing forward with the hydrogen economy, but infrastructure development costs are a challenge. NTT's concept is very informative. Communication conduits are spread throughout Korea as well, so a similar approach might be possible.
In Poland, transitioning away from coal is a challenge, but hydrogen infrastructure development takes time. NTT's idea of utilizing existing infrastructure has the potential to accelerate the transition. This is a case the EU should pay attention to.
Australia aims to be a hydrogen exporter, but domestic transportation infrastructure is also important. In our vast country, utilizing existing infrastructure like NTT could lead to significant cost savings. I'd like to know more technical details.
Brazil has high potential for green hydrogen production, but transportation infrastructure is lacking. NTT's concept might serve as a reference model for developing countries too. Reducing initial investment by utilizing existing infrastructure is attractive.
Decarbonization is progressing in Sweden, but hydrogen infrastructure is still developing. Creative approaches like NTT's are worth considering in Nordic countries too. I see particular potential for deployment in urban areas.
Ireland has abundant wind power, but we need means to convert and transport surplus electricity as hydrogen. NTT's communication conduit utilization could be an effective solution for small island nations too. This is an interesting initiative.
Honestly, some argue that hydrogen has significant energy loss during transport and electrification is more efficient. NTT's concept is interesting, but I think there's still room for debate about the merits of a hydrogen society itself.
The Netherlands is developing the Port of Rotterdam as a hydrogen import hub, but inland transportation is a challenge. NTT's concept is a useful approach for hydrogen supply to urban areas. It might also be applicable to our cross-border pipeline plans with Germany.
Italy has plans to upgrade the existing gas grid for hydrogen compatibility, but utilizing completely different infrastructure like NTT wasn't considered. It's an innovative idea, but I'm curious about compatibility with EU regulations.
Canada has potential as a hydrogen producer, but transportation across our vast territory is a challenge. NTT's concept is cost-efficient and interesting, but there are Canada-specific challenges like conduit durability in extreme cold climates.
India has a rapidly growing hydrogen market, but infrastructure development is lagging. NTT's concept could serve as a reference model for emerging countries to realize a hydrogen society. The cost reduction aspect is particularly important.
I have concerns about hydrogen leakage risks. I'd like to see more detailed safety data on whether conduits designed for communication are suitable for hydrogen transport. I acknowledge the technical potential, but careful evaluation is needed.