Publications

This study aims to assess the potential risks of setting up a hydrogen infrastructure in the Netherlands. An integrated risk assessment framework capable of analyzing projects identifying risks and comparing projects is used to identify and analyze the main risks in the upcoming Dutch hydrogen infrastructure project. A time multiplier is added to the framework to develop parameters. The impact of the different risk categories provided by the integrated framework is calculated using the discounted cash flow (DCF) model. Despite resource risks having the highest impact scope risks are shown to be the most prominent in the hydrogen infrastructure project. To present the DCF model results a risk assessment matrix is constructed. Compared to the conventional Risk Assessment Matrix (RAM) used to present project risks this matrix presents additional information in terms of the internal rate of return and risk specifics.

Fuel cells as clean power sources are very attractive for the maritime sector which is committed to sustainability and reducing greenhouse gas and atmospheric pollutant emissions from ships. This paper presents a technological review on fuel cell power systems for maritime applications from the past two decades. The available fuels including hydrogen ammonia renewable methane and methanol for fuel cells under the context of sustainable maritime transportation and their pre-processing technologies are analyzed. Proton exchange membrane molten carbonate and solid oxide fuel cells are found to be the most promising options for maritime applications once energy efficiency power capacity and sensitivity to fuel impurities are considered. The types layouts and characteristics of fuel cell modules are summarized based on the existing applications in particular industrial or residential sectors. The various research and demonstration projects of fuel cell power systems in the maritime industry are reviewed and the challenges with regard to power capacity safety reliability durability operability and costs are analyzed. Currently power capacity costs and lifetime of the fuel cell stack are the primary barriers. Coupling with batteries modularization mass production and optimized operating and control strategies are all important pathways to improve the performance of fuel cell power systems.

The Hy4Heat Safety Assessment has focused on assessing the safe use of hydrogen gas in certain types of domestic properties and buildings. The summary reports (the Precis and the Safety Assessment Conclusions Report) bring together all the findings of the work and should be looked to for context by all readers. The technical reports should be read in conjunction with the summary reports. While the summary reports are made as accessible as possible for general readers the technical reports may be most accessible for readers with a degree of technical subject matter understanding. All of the safety assessment reports have now been reviewed by the HSE.<br/><br/>A comparative risk assessment of natural gas versus hydrogen gas including a quantitative risk assessment; and identification of control measures to reduce risk and manage hydrogen gas safety for a community demonstration.

Turquoise hydrogen is produced from methane cracking a cleaner alternative to steam methane reforming. This study looks at two proposed systems based on solar methane cracking for low-carbon fuel production. The systems utilize different pathways to convert the hydrogen into a suitable form for transportation and utilize the carbon solid by-product. A direct carbon fuel cell is integrated to utilize the carbon and capture the CO2 emissions. The CO2 generated is utilized for fuel production using CO2 hydrogenation or co-electrolysis. An advanced exergetic analysis is conducted on these systems using Aspen plus simulations of the process. The exergetic efficiency waste exergy ratio exergy destruction ratio exergy recoverability ratio environmental effect factor and the exergetic sustainability index were determined for each system and the subsystems. Solar methane cracking was found to have an environmental effect factor of 0.08 and an exergetic sustainability index of 12.27.

The investigation of the various heat management concepts using LH2 requires the development of a modeling environment coupling the cryogenic hydrogen fuel system with turbofan performance. This paper presents a numerical framework to model hydrogen-fueled gas turbine engines with a dedicated heat-management system complemented by an introductory analysis of the impact of using LH2 to precool and intercool in the compression system. The propulsion installations comprise Brayton cycle-based turbofans and first assessments are made on how to use the hydrogen as a heat sink integrated into the compression system. Conceptual tubular compact heat exchanger designs are explored to either precool or intercool the compression system and preheat the fuel to improve the installed performance of the propulsion cycles. The precooler and the intercooler show up to 0.3% improved specific fuel consumption for heat exchanger effectiveness in the range 0.5–0.6 but higher effectiveness designs incur disproportionately higher pressure losses that cancel-out the benefits.

The National Renewable Energy Laboratory’s (NREL) Hydrogen Safety Research and Development (HSR&D) program in collaboration with the University of Maryland’s Systems Risk and Reliability Analysis Laboratory (SyRRA) are working to improve reliability and reduce risk in hydrogen systems. This approach strives to use quantitative data on component leaks and failures together with Prognosis and Health Management (PHM) and Quantitative Risk Assessment (QRA) to identify atrisk components reduce component failures and downtime and predict when components require maintenance. Hydrogen component failures increase facility maintenance cost facility downtime and reduce public acceptance of hydrogen technologies ultimately increasing facility size and cost because of conservative design requirements. Leaks are a predominant failure mode for hydrogen components. However uncertainties in the amount of hydrogen emitted from leaking components and the frequency of those failure events limit the understanding of the risks that they present under real-world operational conditions. NREL has deployed a test fixture the Leak Rate Quantification Apparatus (LRQA) to quantify the mass flow rate of leaking gases from medium and high-pressure components that have failed while in service. Quantitative hydrogen leak rate data from this system could ultimately be used to better inform risk assessment and Regulation Codes and Standards (RCS). Parallel activity explores the use of PHM and QRA techniques to assess and reduce risk thereby improving safety and reliability of hydrogen systems. The results of QRAs could further provide a systematic and science-based foundation for the design and implementation of RCS as in the latest versions of the NFPA 2 code for gaseous hydrogen stations. Alternatively data-driven techniques of PHM could provide new damage diagnosis and health-state prognosis tools. This research will help end users station owners and operators and regulatory bodies move towards risk-informed preventative maintenance versus emergency corrective maintenance reducing cost and improving reliability. Predictive modelling of failures could improve safety and affect RCS requirements such as setback distances at liquid hydrogen fueling sites. The combination of leak rate quantification research PHM and QRA can lead to better informed models enabling data-based decision to be made for hydrogen system safety improvements.

The shipping industry is becoming increasingly aware of its environmental responsibilities in the long-term. In 2018 the International Maritime Organization (IMO) pledged to reduce greenhouse gas (GHG) emissions by at least 50% by the year 2050 as compared with a baseline value from 2008. Ammonia has been regarded as one of the potential carbon-free fuels for ships based on these environmental issues. In this paper we propose four propulsion systems for a 2500 Twenty-foot Equivalent Unit (TEU) container feeder ship. All of the proposed systems are fueled by ammonia; however different power systems are used: main engine generators polymer electrolyte membrane fuel cell (PEMFC) and solid oxide fuel cell (SOFC). Further these systems are compared to the conventional main engine propulsion system that is fueled by heavy fuel oil with a focus on the economic and environmental perspectives. By comparing the conventional and proposed systems it is shown that ammonia can be a carbon-free fuel for ships. Moreover among the proposed systems the SOFC power system is the most eco-friendly alternative (up to 92.1%) even though it requires a high lifecycle cost than the others. Although this study has some limitations and assumptions the results indicate a meaningful approach toward solving GHG problems in the maritime industry.

This work focuses on tests for control reserve of a novel Power-to-Gas-to-Power platform based on proton exchange membrane technologies and on pure oxygen instead of air in the re-electrification process. The technologies are intended as a further option to stabilize the power system therefore helping integrating renewable energy into the power system. The tests are based on the pre-qualification tests used by Swissgrid but are not identical in order to capture the maximum dynamics by the plants. The main characteristics identified are the ramping capabilities of ±8% per unit per second for the electrolyzer system and ±33% per unit per second for the fuel cell system. The ramping capabilities are mainly limited by the underlying processes of polymer electrolyte membrane technologies. Additionally the current and projected round-trip efficiencies for Power-to-Gas-to-Power of 39% in 2025 and 48% in 2040 are derived. Furthermore during the successful tests the usage of oxygen in the present Power-to-Gas and Gas-to-Power processes and its influence on the dynamics and the round-trip efficiency was assessed. In consequence fundamental data on the efficiency and the dynamics of the Power-to-Gas-to-Power technologies is presented. This data can serve as basis for prospective assessments on the suitability of the technologies investigated for frequency control in power systems.

This statutory report provides a comprehensive overview of the UK Government’s progress to date in reducing emissions. It is accompanied by a new Monitoring Framework which details the CCC’s updated approach to tracking real-world progress through a host of new indicators.<br/>This is a pivotal point in the UK’s journey to Net Zero. The UK is one of the few countries with emissions targets in line with the long-term temperature goal of the Paris Agreement. Policy ambition has moved substantially with the publication of the UK’s Net Zero Strategy. Now is the time to deliver the promised action.

One option to decarbonise residential heat in the UK is to convert the existing natural gas networks to deliver hydrogen. We review the technical feasibility of this option using semistructured interviews underpinned by a literature review and we assess the potential economic benefits using the UK MARKAL energy systems model. We conclude that hydrogen can be transported safely in the low-pressure pipes but we identify concerns over the reduced capacity of the system and the much lower linepack storage compared to natural gas. New hydrogen meters and sensors would have to be fitted to every building in a hydrogen conversion program and appliances would have to be converted unless the government was to legislate to make them hydrogen-ready in advance. Converting the gas networks to hydrogen is a lower-cost residential decarbonisation pathway for the UK than those identified previously. The cost-optimal share of hydrogen is sensitive to the conversion cost and to variations in the capital costs of heat pumps and micro-CHP fuel cells. With such small cost differentials between technologies the decision to convert the networks will also depend on non-economic factors including the relative performance of technologies and the willingness of the government to organise a conversion program.