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The UN concept of “sustainable development” is increasingly penetrating various spheres of life, subordinating not only political interests, but also forcing economics and science to work closely together to preserve a favorable environment, biodiversity and reduce climate emissions. On the one hand, in the current global paradigm, this attitude is mainly positive, as it aims to achieve the goals of the Paris Climate Agreement, prevent negative environmental impacts and other high goals, including the protection of the interests of future generations. However, the “green fever” that is sweeping the world, namely the race of states and various international organizations, carries significant risks. The goals and economic targets set by Governments are sometimes not just overly ambitious, but simply unrealistic and utopian, as in the case of the transition to blue hydrogen in the next five years. In addition, another problem associated with the implementation of the principles of sustainable development is the problem of abuse of rights in the financial market, as well as increasing the competitiveness and attractiveness of investments in this area through the issuance of specialized securities, the so-called “green bonds” or their specialized variety of “blue bonds”. However, it should be noted that with all the marketing activities that accompany the issuance of each financial instrument of this type, it is currently impossible to ensure their liquidity solely for supposed good purposes. Thus, without a clearly formulated economic plan confirming the real financial attractiveness of both projects on the introduction of blue water and projects on the issue of blue bonds, both are doomed to very low performance. [ABSTRACT FROM AUTHOR]

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Methane pyrolysis in molten salts has the potential to provide low-cost, low-CO 2 emission H 2 on an industrial scale. The alkali halides (NaBr, KBr, KCl, NaCl, (Na,K)Br) are inexpensive and environmental benign salts, which may facilitate sequestration or sales of the produced carbon even if low-to-moderate amounts of salt remain trapped in the carbon. In this novel work, alkali halides have been tested as the liquid reaction media, and the results of kinetic measurements and carbon characterisation are reported. The observed activation energies were found to be in the range 223.5–277.6 kJ mol−1, which is significantly lower than those measured during gas-phase methane pyrolysis (~422 kJ mol−1). After washing procedures with deionised water, the purity of the produced carbon was in the range 91.7–97.4 atom% or 55.0–91.6 wt%, with the carbon purities correlating well with the salt compounds size and salt-carbon wettability. The carbon samples generated in each salt are all low density (<1 g cm−3), highly porous (30.1–75.2%), low surface area (1.84–3.14 m2 g−1) and have relatively low-levels of structural order. The suggested relationships between the salt selection and the carbon purity, the mass fraction and degree of well-ordered carbon as well as surface and pore morphologies can be used to optimise process designs. Furthermore, the relationships could be used to tune the carbon properties to tailor it to the carbon market needs if the carbon is considered as a co-product. Image 1 • Comprehensive assessment of CH 4 pyrolysis in inexpensive, benign molten salts. • Evaluation of reaction kinetics and properties of carbon from molten salts pyrolysis. • Carbon structural order and purity are related to the salt cation radii. • Key insights for designing industrial CH 4 pyrolysis processes and tailoring carbon. • Simple, cost-effective methods to evaluate performance and carbon properties. [ABSTRACT FROM AUTHOR]

As the popularity of fuel cell vehicles continues to rise in the global market, production and supply of low-carbon hydrogen are important to mitigate CO 2 emissions. We propose a design for a hydrogen refueling station with a proton exchange membrane electrolyzer (PEM-EL)-based electrolysis system (EL-System) and photovoltaic generation (PV) to supply low-carbon hydrogen. Hydrogen is produced by the EL-System using electricity from PV and the power grid. The system was formulated as a mixed integer linear programming (MILP) model to allow analysis of optimal operational strategies. Case studies with different objective functions, CO 2 emission targets, and capacity utilization of the EL-System were evaluated. Efficiency characteristics of the EL-System were obtained through measurements. The optimized operational strategies were evaluated with reference to three evaluation indices: CO 2 emissions, capacity utilization, and operational cost of the system. The results were as follows: 1) Regardless of the objective function, the EL-System generally operated in highest efficiency state, and optimal operation depended on the efficiency characteristics of the EL-System; 2) mitigation of CO 2 emissions and increase in capacity utilization of the EL-System required trade-offs; and 3) increased capacity utilization of the EL-System showed two opposing effects on hydrogen retail price. [ABSTRACT FROM AUTHOR]