Biogas is a renewable feedstock that can be used to produce hydrogen through the decomposition of biomethane. However, the economics of the process are not well studied and understood, especially in cases where solid carbons are also produced, and which have a detrimental effect on the performance of the catalysts. The scale, as well as product diversification of a biogas plant to produce hydrogen and other value-added carbons, plays a crucial role in determining the feasibility of biogas-to-hydrogen projects. Through a techno-economic study using the discounted cash flow method, it has been shown that there are no feasible sizes of plants that can produce hydrogen at the target price of USD 3/kg or lower. However, for self-funded anaerobic digestor plants, retrofitting modular units for hydrogen production would only make financial sense at biogas production capacities of more than 412 m³/h. A sensitivity analysis has also shown that the cost competitiveness is dependent on the type of carbon formed, and low-grade carbon black has a negative effect on economic feasibility. Hydrogen produced from biogas would thus not be able to compete with grey hydrogen production but rather with current green hydrogen production costs.

In this paper, we report the synthesis of a Li4Ti5O12/Graphene Nanoribbons (LTO/GNRs) composite using a solid-coating method. Electron microscope images of the LTO/GNRs composite have shown that LTO particles were wrapped around graphene nanoribbons. The introduction of GNRs was observed to have significantly improved the rate performance of LTO/GNTs. The specific capacities determined of the obtained composite at rates of 0.2, 0.5, 1, 2, and 5 C are 206.5, 200.9, 188, 178.1 and 142.3 mAh·g−1, respectively. This is significantly higher than those of pure LTO (169.1, 160, 150, 106 and 71.1 mAh·g−1, respectively) especially at high rate (2 and 5 C). The LTO/GNRs also shows better cycling stability at high rates. Enhanced conductivity of LTO/GNRs contributed from the GNR frameworks accelerated the kinetics of lithium intercalation/deintercalation in LIBs that also leads to excellent rate capacity of LTO/GNRs. This is attributed to its lower charge-transfer resistance (Rct = 23.38 Ω) compared with LTO (108.05 Ω), and higher exchange current density (j = 1.1 × 10−3 mA cm−2)—about 20 times than those of the LTO (j = 2.38 × 10−4 mA cm−2).

Methane pyrolysis offers a viable route for producing low-carbon hydrogen, providing an eco-friendly substitute for traditional techniques such as steam methane reforming. This method thermally breaks down methane (CH₄) into hydrogen gas (H₂) and solid carbon, preventing direct CO₂ emissions during production. Commonly known as “turquoise hydrogen,” this approach generates a valuable solid carbon by-product, which can be captured or used in industrial processes, improving economic feasibility. The technology utilises current natural gas distribution systems, allowing for decentralised hydrogen generation while incorporating renewable energy sources to drive the high-temperature reaction. This chapter thoroughly examines methane pyrolysis, addressing essential chemical mechanisms, catalytic and non-catalytic routes, reactor configurations, and operational issues such as catalyst deactivation and carbon handling. It explores the importance of operating conditions, kinetic modelling, and new commercial initiatives by firms such as Monolith Materials and Hazer Group, showcasing scalability and market prospects. The advantages for the environment and the economy depend on aspects such as methane leaks, the carbon intensity of energy sources, and the final application of solid carbon products, including carbon black or graphite. Life cycle assessments show that methane pyrolysis, when using clean energy, can attain a carbon footprint much lower than the conventional methods. Methane pyrolysis connects fossil fuel infrastructure to a low-carbon future, positioning it as a key technology for the hydrogen economy, with continuous advancements in catalysts and reactor designs set to improve its scalability and influence.