Conversion of Natural Gas pipelines to Hydrogen?

[Sparty]

Key research and development areas for hydrogen pipeline coatings:

key hydrogen pipeline conversion projects that have been announced or are underway:
Major European Projects:

H2ercule (Netherlands/Germany)


Converting existing natural gas pipelines
Gasunie and TenneT involvement
North Sea to Ruhr region industrial corridor
Focus on industrial hydrogen transport


European Hydrogen Backbone


Multiple countries involved
~75% planned to use converted gas pipelines
Phased approach through 2040
Mix of new and converted infrastructure

North American Projects:

HyBlend (US DOE project)


Testing different blend percentages
Material compatibility studies
Multiple pipeline operators involved
Focus on partial hydrogen blending

Asia-Pacific:

Japan's Hydrogen Pipeline Initiatives


Primarily new construction rather than conversion
Some testing of existing infrastructure
Focus on industrial ports

Key Technical Learnings:

Pipeline Assessment Methods


Material testing protocols
Inspection requirements
Fitness-for-service criteria


Conversion Approaches


Section-by-section conversion
Parallel system operation
Purging and commissioning procedures

[Sparty]

Each major area in detail.

H2ercule Project (Netherlands/Germany):

Technical Details:

Around 1,100 km of existing natural gas infrastructure being converted
Operating pressure target: 50-60 bar
Diameter: Primarily 36-48 inch pipelines
Capacity: ~1.5 million tonnes hydrogen per year by 2030

Conversion Process:

Pipeline integrity assessment using smart pigs
Valve replacement program for hydrogen service
Compressor station modifications
Installation of new hydrogen-specific monitoring systems

Timeline:

Initial assessment phase: 2021-2023
First conversions: 2025
Full operation: 2030
Gradual scaling up approach

Challenges:

Dealing with mixed material types in existing lines
Maintaining supply during conversion
Cross-border regulatory alignment
Material qualification programs


HyBlend Research Program:

Material Testing:

Comprehensive testing of pipeline steels:

X42, X52, X65, X70 grades
Various vintage materials
Different welding techniques
Coating compatibility



Blend Percentage Findings:

Up to 20% hydrogen generally acceptable without major modifications
20-50% requires case-by-case assessment


50% typically requires significant modifications


Temperature effects on blend behavior

Pipeline Operator Experience:

Development of new inspection protocols
Modified emergency response procedures
Training requirements identified
Risk assessment methodologies

Technical Solutions:

New sealing technologies developed
Modified compression solutions
Advanced monitoring systems
Leak detection adaptations


Technical Conversion Process:

Assessment Methods:

In-line inspection requirements
Material sampling protocols
Fitness-for-service criteria
Risk-based assessment approach

Pipeline Preparation:

Cleaning requirements:

Chemical cleaning to remove hydrocarbons
Mechanical cleaning for scale/debris
Drying requirements
Surface preparation for coating



Material Replacements:

Valve replacement criteria
Gasket and seal specifications
Compression system modifications
Instrumentation updates

Testing/Certification:

Pressure testing protocols
Leak testing methods
Commissioning procedures
Certification requirements
Regulatory compliance verification


Economic Analysis:

Conversion Costs:

Assessment phase: $50-100k per km
Basic conversion: $200-500k per km
Full upgrade: $1-2M per km
Compressor station modifications: $5-20M each

Operating Costs:

Higher compression costs for hydrogen
Modified maintenance requirements
New inspection protocols
Training and certification

Business Case Factors:

Hydrogen demand projections
Carbon price assumptions
Government incentives
Infrastructure utilization rates

Funding Approaches:

Government grants
Public-private partnerships
Industrial consortium funding
Carbon credit mechanisms

Ongoing Research Needs:

Materials:


Long-term hydrogen effects
Fatigue behavior
Weld performance
Coating durability


Operations:


Flow modeling
Compression optimization
Blending control
Safety systems


Monitoring:


Real-time hydrogen detection
Leak detection systems
Material degradation monitoring
Performance optimization

Key Learnings So Far:
Technical:

Material compatibility is highly dependent on operating conditions
Successful conversion requires comprehensive system approach
Monitoring and safety systems need significant modification
Quality control during conversion is critical

Economic:

Conversion generally cheaper than new construction
Costs highly variable based on pipeline condition
Operating costs higher than natural gas
Business case improves with scale

Regulatory:

Standards still evolving
Safety requirements being developed
Cross-border coordination needed
Certification processes being established

[Sparty]

As of today there isn't a clear "showpiece" complete conversion of an LNG/natural gas pipeline to 100% hydrogen service at commercial scale. Most projects are either:

In Planning/Construction:


H2ercule project is often cited but still in progress
European Backbone segments are mostly planned
Many announcements but few completions


Partial Implementation:


Small test sections
Limited blend percentages (<20% hydrogen)
Pilot scale demonstrations


Closest Examples:


Air Liquide has operated some dedicated hydrogen pipelines (but these were purpose-built, not conversions)
HyStock project in Netherlands (small scale)
Some industrial corridor projects (limited scope)

The lack of a clear showpiece project highlights some important points:

Technology is still maturing
Regulatory frameworks still developing
Many projects announced but still in early stages
Most success stories are with new construction rather than conversion

[Sparty]

Hmmm how do hydrogen powered vehicles get their H2? How is it transported to the "bowsers"?

Current Common Methods:

Tube Trailers to Station


Compressed gas in cylindrical tubes
Typically 200-500 bar pressure
Special composite or steel tubes
Entire trailer exchanged or decoupled
Most common current method


Station Storage & Dispensing:


Multi-stage compression at station
Storage cascades (low/medium/high pressure banks)
Typically stored at 450-500 bar
Dispensed at 700 bar for passenger vehicles
350 bar for buses/trucks
Cooling systems required (-40°C target)
Special dispensing nozzles/protocols


Pipeline Supply (Limited Locations):


Some industrial areas have H2 pipelines
Direct connection to stations
More common in places like Germany/Netherlands
Requires local compression

Key Technical Elements:
Compression Systems:

Multi-stage compression
Oil-free design
Special sealing systems
Cooling between stages
Buffer storage

Safety Systems:

Leak detection
Emergency shutdown
Excess flow protection
Grounding systems
Vent stacks
Fire protection