Publications

National Grid Gas Transmission (NGGT) contracted Rosen UK Ltd (Rosen) and The University of Warwick UK (Warwick) to conduct a literature review on the subject of “impact of hydrogen conveyance on the performance of cathodic protection (CP) and pipeline coating degradation”. NGGT’s motivation for this project comes as part of the route to Net Zero with NGGT looking at opportunities to increase the percentage of hydrogen transported within natural gas. As the percentage of hydrogen increases there may be increased risk for the evolution of atomic hydrogen which could permeate through the steel pipe and affect external coatings and the efficacy of CP polarization potentials. Pertaining to the above NGGT’s goal is to gain an appreciation of the work that has been undertaken on coatings and CP systems of hydrogen pipelines and what corrosion protection currently utilized on hydrogen pipelines worldwide as well as reported effects of hydrogen on the behaviour of coating

types with or without impressed voltage. Specifically the focus was to identify potential impacts of hydrogen on coating performance adhesion and CP polarization for differing concentration levels of hydrogen being transported at a range of pressures for:

1. A selection of applied and factory coatings and coating types both for a range of aged and new applications.

2. A selection of coating holiday (coating defect) sizes at varying levels of CP polarization.

The project was divided into three work packages:

1. Work Package 1: Literature Review – Rosen as an Industrial Partner.

2. Work Package 2: Literature Review – Warwick as an Academic Partner.

3. Work Package 3: Reporting – presented as a joint effort between Rosen and Warwick.

During the execution of the projects all parties involved participated in two interactive on-line workshops; Workshop 1 was held on the 20th of December 2022 and Workshop 2 on the 2nd of May 2023. Both workshops served as platforms for sharing work progress and obtained results and their discussion; presentation slides delivered at both workshops can be found in Appendix A – Workshop 1 Presentations and Appendix B – Workshop 2 Presentation.

The current document presents the final stage of the project i.e. Work Package 3.

This report was submitted to HSE for their assessment of the safety evidence for 100% hydrogen heating which can be found at Hydrogen heating: HSE assessment of the safety evidence - GOV.UK.

Queries should be directed to DESNZ: https://www.gov.uk/guidance/contact-desnz.

Proton transport plays a crucial role in acidic oxygen evolution reaction process. Iridium oxide (IrOx) exhibits good stability yet its catalytic activity remains insufficient at high current density. Trace sulfonates introduced into electrocatalysts can enhance the proton transfer process; however their significant leaching compromises catalyst stability. Herein we report a sulfonic groups ( − SO3H) grafted catalyst Ir/IrOx ~ SO3H featuring covalent bonding between sulfonic groups and iridium oxide. The anchored sulfonic groups facilitate enhancing the proton transfer process and promote the formation of *OOH intermediates thereby accelerating the oxygen evolution reaction kinetics. A proton exchange membrane water electrolysis assembled with an Ir/IrOx ~ SO3H anode needs a cell voltage of only 1.75 V at 3.0 A cm−2 and stably operates over 1000 h without leaching of sulfonic groups outperforming a water electrolysis assembled with a commercial iridium oxide anode in activity. Moreover the elevated surface potential of catalyst particles alleviates their agglomeration which is benefit to the industrial membrane electrode preparation. The strong bonding strategy holds promise for advancing the development of sulfonates-grafted catalysts in energy conversion applications.

As part of Germany’s LuFo 6 program ’WOTAN’ Rolls-Royce Deutschland (RRD) investigated direct H2 combustion in Rich-Quench-Lean (RQL) mode. Two H2-injectors previously tested under atmospheric conditions were evaluated at elevated pressures and preheat temperatures in the High-pressure Optical Triple Sector (HOTS) at DLR’s HBK1 facility. These tests served as a safety check for the following full-annular test at take-off operating condition. Both injectors were tested at 7% take-off load with variations in air-to-fuel ratio (AFR) to examine the effects of stoichiometry on flame characteristics and NOx emissions. Flame imaging was conducted using ultra-violet (UV)- near-infrared (NIR)- and visible spectrum diagnostics to visualize OH* water vapor and flame luminosity. Exhaust gas measurements were performed downstream of the combustion chamber’s convergent section. Both injectors demonstrated stable combustion across all test conditions maintaining consistent flame position and shape despite changes in pressure temperature and AFR. However significant differences in NOx emission index (EI) were observed between the injectors. The injector with higher NOx emissions exhibited flame anchoring at the injector exit while the other maintained a lifted flame reducing thermal NOx formation. Additionally AFR variation revealed different sensitivities of EI NOx attributed to distinct fuel placement and local stoichiometry. One injector developed a second heat release zone in the inner recirculation region at higher AFRs further contributing to elevated NOx.

This study evaluates the environmental sustainability of hydrogen production from highcalorific mixed waste gasification through a Gate-to-Gate (GtG) Life Cycle Assessment (LCA) based on operational data from a 2 TPD pilot plant. The Global Warming Potential (GWP) was calculated to be 9.80 kg CO2-eq per kg of H2 produced. A contribution analysis identified the primary environmental hotspots as external electricity consumption (37.0%) chelated iron production for syngas cleaning (19.5%) externally supplied oxygen 18.6%) and plant construction (12.3%). A comparative analysis contextualized within South Korea’s energy structure demonstrates this GWP is competitive with regionally contextualized Steam Methane Reforming (SMR) and lower than coal gasification. Furthermore a scenario analysis based on national energy policies reveals a clear pathway for GWP reduction. Aligning with the 2030 renewable energy target (20% RE share) reduces the GWP to 9.14 kg CO2-eq while a full transition to 100% wind power lowers it to 6.27 kg CO2-eq. These findings establish this Waste-to-Hydrogen (WtH) technology as a promising transitional solution that simultaneously valorizes problematic waste. This research provides a critical empirical benchmark for the technology’s commercialization and establishes an internationally transferable framework. It confirms that the technology’s ultimate environmental sustainability is intrinsically linked to the decarbonization of the local electricity grid.