Evaluation of Turquoise Hydrogen Production Technologies (24.RP2.0205) – Completed

Introduction and Objectives

A wide range of methane pyrolysis technologies are under development, including thermal, plasma-based, microwave-assisted and catalytic processes. These technologies differ significantly in operating conditions, energy requirements, technology readiness and, importantly, the type and quality of carbon produced. Carbon products can range from relatively low-value carbon black-like materials to graphitic carbon, carbon nanotubes and other advanced carbon materials. Consequently, methane pyrolysis technologies need to be evaluated not only in terms of hydrogen production, but also in terms of carbon formation, downstream processing requirements and potential end-use markets.

The project therefore aimed to:

• Identify and classify the major methane pyrolysis technology pathways;
• Investigate how different technologies and operating conditions influence the type and characteristics of solid carbon produced;
• Assess the market demand, potential value and applications of methane-pyrolysis-derived carbon products;
• Evaluate opportunities for upgrading lower-value carbon into higher-value products;
• Undertake process-level assessments of selected methane pyrolysis pathways, including indicative mass and energy balances; and
• Identify key technical and knowledge gaps and opportunities for future development of turquoise hydrogen technologies.

Project Findings

The project established that methane pyrolysis should be assessed as a hydrogen and carbon co-production process, rather than solely as a hydrogen production technology. The type, quality, quantity and potential market for the solid carbon co-product have a significant influence on the technical and commercial viability of each pathway.

2.1 Technology Landscape and Carbon Products

The assessment identified several major methane pyrolysis technology families, including thermal, thermal plasma, microwave-assisted, carbon-catalysed, metal-oxide-catalysed and floating-catalyst chemical vapour deposition (FCCVD) processes. These technologies operate under different reaction environments and produce distinctly different carbon materials.

The carbon products reported across these technologies range from low-structure carbon black-like materials to pyrolytic and semi-graphitic carbon, synthetic graphite, carbon nanotubes and other nanostructured carbons. Importantly, the carbon produced within the reactor establishes the baseline properties of the material and limits the extent to which it can subsequently be upgraded. Therefore, selection of the methane pyrolysis technology is intrinsically linked to the potential carbon product and its end-use market.

2.2 Carbon Markets and Upgrading Opportunities

The assessment identified a significant trade-off between market size and product value. Large-volume markets such as construction materials, rubber and plastics have greater capacity to absorb carbon production but generally offer lower product value. In contrast, battery materials, synthetic graphite, carbon nanotubes and graphene can attract substantially higher value but have smaller markets and more stringent product-quality requirements.

A range of post-processing options, including purification, milling, activation, thermal treatment and graphitisation, can improve carbon properties and expand potential applications. However, upgrading introduces additional energy consumption, processing complexity and cost, and cannot necessarily convert all methane-pyrolysis-derived carbons into high-value products.

2.3 Process-Level Assessment

Four representative methane pyrolysis pathways were selected for more detailed process-level assessment:

• Plasma-based methane pyrolysis;
• Catalytic methane pyrolysis using Fe/Ni catalysts;
• Iron-ore-based catalytic methane pyrolysis; and
• Production of synthetic graphite through a tar/pitch intermediate pathway.

Block flow diagrams and indicative mass and energy balances were developed for these pathways to enable comparison of process configuration, energy requirements, carbon products and technology maturity.

The comparison showed that no single pathway simultaneously provides high technology maturity, low energy consumption and high-value carbon production. Plasma-based technologies are currently among the most mature and scalable but have relatively high energy requirements. FCCVD pathways can produce high-value carbon nanotubes and nanofibres but have very high energy intensity and limited scalability. Metal-oxide-catalysed routes offer lower energy requirements and potential industrial integration but produce mixed carbon products requiring further development. The graphite-from-tar pathway offers a potential route to high-value synthetic graphite but currently has low carbon yield and remains at relatively low technology readiness.

2.4 Overall Finding

The central finding of the project is that the commercial development of methane pyrolysis cannot be based on hydrogen performance alone. Process design, carbon formation, downstream upgrading and end-use markets need to be considered together. In the near term, technologies producing carbon compatible with established, relatively large-volume markets appear better positioned for deployment, while pathways targeting high-value advanced carbon products represent longer-term opportunities requiring further technology development, cost reduction and market growth.

Recommendations

Based on the outcomes of this project, future development of methane pyrolysis should consider hydrogen production and carbon utilisation as an integrated system. The following priorities are recommended:

• Target carbon markets early in technology development. Reactor and process selection should be aligned with realistic carbon product specifications and market volumes, rather than treating carbon as a generic by-product. Near-term opportunities are more likely in relatively large-volume markets where product specifications can be achieved with limited post-processing.
• Improve carbon characterisation and product validation. Future experimental and pilot-scale studies should provide systematic characterisation of carbon structure, morphology, purity, particle size and relevant application-specific properties. This is required to establish whether methane-pyrolysis-derived carbon can reliably meet commercial product specifications.
• Evaluate carbon upgrading on a process and economic basis. Purification, milling, activation, thermal treatment and graphitisation can increase carbon value, but also introduce additional energy demand, cost and process complexity. Future assessments should quantify these trade-offs alongside hydrogen production performance.
• Progress promising pathways through targeted pilot-scale validation. Particular attention should be given to pathways that combine reasonable technology maturity and energy performance with carbon products suited to established or emerging markets. The four pathways assessed in this project provide a basis for more detailed experimental, techno-economic and scale-up studies.
• Consider market scale, logistics and certification in future techno-economic assessments. Carbon collection, treatment, storage, transport and market certification should be incorporated into future assessments. Co-location of methane pyrolysis facilities with potential carbon users should also be investigated as a means of reducing logistics costs and improving overall project economics.

Overall, future work should focus on demonstrating an integrated hydrogen-plus-carbon value proposition, with technology development guided by achievable carbon quality, realistic market demand, energy requirements and overall process economics.