Hydrogen Blending

Climate change is one of today’s most pressing global challenges. Since the emission of greenhouse gases is often closely related to the use and supply of energy the goal to avoid emissions requires a fundamental restructuring of the energy system including all parts of the technology chains from production to end-use. Natural gas is today one of the most important primary energy sources in Europe with utilization ranging from power generation and industry to appliances in the residential and commercial sector as well as mobility. As natural gas is a fossil fuel gas utilization is thus responsible for significant emissions of carbon dioxide (CO₂ ) a greenhouse gas. However the transformation of the gas sector with its broad variety of technologies and end-use applications is a challenge as a fuel switch is related to changing physical properties. Today the residential and commercial sector is the biggest end user sector for natural gas in the EU both in terms of consumption and in the number of installed appliances. Natural gas is used to provide space heating as well as hot water and is used in cooking and catering appliances with in total about 200 million gas-fired residential and commercial end user appliances installed. More than 40 % of the EU gas consumption is accounted for by the residential and commercial sector. The most promising substitutes for natural gas are biogases and hydrogen. The carbon-free fuel gas hydrogen may be produced e.g. from water and renewable electricity; therefore it can be produced with a greatly lowered carbon footprint and on a very large scale. As a gaseous fuel it can be transported stored and utilised in all end-use sectors that are served by natural gas today: Power plants industry commercial appliances households and mobility. Technologies and materials however need to be suitable for the new fuel. The injection of hydrogen into existing gas distribution for example will impact all gas-using equipment in the grids since these devices are designed and optimized to operate safely efficiently and with low pollutant emissions with natural gas as fuel. The THyGA project1 focusses on all technical aspects and the regulatory framework concerning the potential operation of domestic and commercial end user appliances with hydrogen  / natural gas blends. The THyGA deliverables start with theoretical background from material science (D2.4) and combustion theory (this report) and extend to the project’s experimental campaign on hydrogen tolerance tests as well as reports on the status quo and potential future developments on rules and standards as well as mitigation strategies for coping with high levels of hydrogen admixture. By this approach the project aims at investigating which levels of hydrogen blending impact the various appliance technologies to which extent and to identify the regime in which a safe efficient and low-polluting operation is possible. As this is in many ways a question of combustion this report focuses on theoretical considerations about the impact of hydrogen admixture on combustion processes. The effects of hydrogen admixture on main gas quality properties as well as combustion temperatures laminar combustion velocities pollutant formation (CO NOx) safety-related aspects and the impact of combustion control are discussed. This overview provides a basis for subsequent steps of the project e.g. for establishing the testing program. A profound understanding of the impact on hydrogen on natural gas combustion is also essential for the development of mitigation strategies to reduce potential negative consequences of hydrogen admixture on appliances.

This is part one. Part two of this project can be found at this link

Hydrogen is increasingly receiving a primary role as an energy vector in ensuring the achievement of the European decarbonization goals by 2050. In fact Hydrogen could be produced also by electrolysis of water using renewable sources such as photovoltaic and wind power being able to perform the energy storage function as well as through injection into natural gas infrastructures. However hydrogen injection directly impacts thermodynamic properties of the gas itself such as density calorific value Wobbe index sound speed etc. Consequently this practice leads to changes in metrological behavior especially in terms of volume and gas quality measurements. In this paper the authors present an overview on the impact of hydrogen injection in natural gas measurements. In particular the changes in thermodynamic properties of the gas mixtures with different H2 contents have been evaluated and the effects on the accuracy of volume conversion at standard conditions have been investigated both on the theoretical point of view and experimentally. To this end the authors present and discuss the effect of H2 injection in gas networks on static ultrasonic domestic gas meters both from a theoretical and an experimental point of view. Experimental tests demonstrated that ultrasonic gas meters are not significantly affected by H2 injection up to about 10%.

In recent years various studies have put forward the prospect of relying on low-carbon or renewable gases such as green hydrogen (H2) or biomethane to replace the supply of natural gas. Hydrogen in particular is receiving much attention as a versatile energy carrier that could complement direct electrification in a plethora of end-uses and questions over its production and deployment play an important part in the ongoing discussions around the energy chapters of the European Commission’s Green Deal agenda.

The aim of the short study was to assess the technical feasibility emission savings and cost impacts of the addition of hydrogen to the existing gas transport network the so-called practice of “hydrogen blending” which is currently being discussed as a deployment pathway in the context of the review of the EU Gas Market Regulation (GMR) and the Trans-European Networks for Energy (TEN-E) regulation.

The document can be downloaded from their website

Hydrogen is increasingly being positioned as an important component of the UK’s Net Zero ambitions and commitments. In particular hydrogen could be an appropriate way to decarbonise the heat produced for domestic and industrial buildings. It is possible that hydrogen could replace natural gas in the UK gas network achieving key carbon emissions reduction targets while enabling homes to be heated to a similar level and standard as they currently are.<br/>In the interim small amounts of hydrogen will soon be blended into current natural gas supplies. The premise of this idea is to blend hydrogen into the existing gas network in small enough quantities to not require any adjustments to domestic cookers boilers and other gas-fired appliances but in large enough quantities to generate significant immediate reductions in carbon emissions. Three trials will take place between 2019 and 2022 as part of the HyDeploy project with the aim of demonstrating that hydrogen blending can occur at scale with no safety implications and no disruption to users.<br/>Public perceptions and acceptance of hydrogen will be pivotal in this scenario. At present there is very little indication of how acceptable hydrogen will be for heating homes and questions around safety cost and performance are only beginning to be understood and addressed.<br/>This report investigates public perceptions of blended hydrogen as a fuel for UK homes. In March 2019 we administered a survey to a sample (n=742) representative of the UK adult population in terms of age sex ethnicity and personal income. Our survey covered initial perceptions values and knowledge of hydrogen; the possibilities and pitfalls of hydrogen blending; public trust; and participants’ overall support for hydrogen. Key Findings and Conclusions and Recommendations for Policy and Practice follow immediately with the full report beginning on p.6.

This Insight provides an overview of the recent EU Commission Hydrogen Strategy Energy System Integration Strategy and Industrial Strategy focusing on regulatory issues impacting hydrogen. It looks at the proposed classification and preferences for different sources of hydrogen financial and regulatory support for development of hydrogen supply demand and infrastructure as well as potential regulation of hydrogen markets. Whilst the Hydrogen Strategy underlines the need for hydrogen to decarbonise the economy the Insight concludes that the EU has shown a clear preference for hydrogen based on renewable electricity at the expense of low carbon hydrogen from natural gas even though it recognises the need for low carbon hydrogen. In addition further detail is required on the support mechanisms and regulatory framework if development of new hydrogen value chain is to succeed. Lastly there is little sign that the Commission recognises the change in regulatory approach from the current natural gas framework which will be needed because of the different challenges facing the development of a hydrogen market.

Paper can be downloaded on their website

The Fuel Cells & Hydrogen Joint Undertaking (FCH JU) project ""Testing Hydrogen admixture for Gas Appliances"" aka THyGA is proud to release the second deliverable about the impact of hydrogen admixture on combustion processes. This time the report explores the expected impact of H2NG on a range of appliance designs installed in the EU.



After the deliverable D2.2 dedicated to the theorical estimation of the impact of H2 admixture THyGA reviews results from the litterature to evaluate available knowledge on CO and NOx formation overheating flame temperature flashback H₂ leakage operational implications and efficiency of appliances supplied with H2NG blends. Learn more and read deliverable D2.3.



Climate change is one of today’s most pressing global challenges. Since the emission of greenhouse gases is often closely related to the use and supply of energy the goal to avoid emissions requires a fundamental restructuring of the energy system including all parts of the technology chains from production to end-use. Natural gas is today one of the most important primary energy sources in Europe with utilization ranging from power generation and industry to appliances in the residential and commercial sector as well as mobility. As natural gas is a fossil fuel gas utilization is thus responsible for significant emissions of carbon dioxide (CO₂₎ a greenhouse gas.



This is part two. Part one of this project can be found at this link

Hydrogen can be used to reduce carbon emissions by blending into other gaseous energy carriers such as natural gas. However hydrogen blending into natural gas has important implications for safety which need to be evaluated. Hydrogen has different physical properties than natural gas and these properties affect safety evaluations concerning a leak of the blended gas. The intent of this report is to begin to investigate the safety implications of blending hydrogen into the natural gas infrastructure with respect to a leak event from a pipeline. A literature review was conducted to identify existing data that will better inform future hazard and risk assessments for hydrogen/natural gas blends. Metrics with safety implications such as heat flux and dispersion behavior may be affected by the overall blend ratio of the mixture. Of the literature reviewed there was no directly observed separation of the hydrogen from the natural gas or methane blend. No literature was identified that experimentally examined unconfined releases such as concentration fields or concentration at specific distances. Computational efforts have predicted concentration fields by modified versions of existing engineering models but the validation of these models is limited by the unavailability of literature data. There are multiple literature sources that measured flame lengths and heat flux values which are both relevant metrics to risk and hazard assessments. These data can be more directly compared to the outputs of existing engineering models for validation.

The paper can be downloaded on their website

Due to the increasing share of renewable energy sources in the electrical network the focus on decarbonization has extended into other energy sectors. The gas sector is of special interest because it can offer seasonal storage capacity and additional flexibility to the electricity sector. In this paper we present a new simulation method designed for hydrogen-enriched natural gas network simulation. It can handle different gas compositions and is thus able to accurately analyze the impact of hydrogen injections into natural gas pipelines. After describing the newly defined simulation method we demonstrate how the simulation tool can be used to analyze a hydrogen-enriched gas pipeline network. An exemplary co-simulation of coupled power and gas networks shows that hydrogen injections are severely constrained by the gas pipeline network highlighting the importance and necessity of considering different gas compositions in the simulation.

The first applications of hydrogen in a natural gas grid will be the admixing of low concentrations in an existing distribution grid. For easy quality and process control it is essential to monitor the hydrogen concentration in real time preferably using cost effective monitoring solutions. In this paper we introduce the use of a platinum based hydrogen sensor that can accurately (at 0.1 vol%) and reversibly monitor the concentration of hydrogen in a carrier gas. This carrier gas that can be nitrogen methane or natural gas has no influence on the accuracy of the hydrogen detection. The hydrogen sensor consists of an interdigitated electrode on a chip coated with a platinum nanocomposite layer that interacts with the gas. This chip can be easily added to a gas sensor for natural gas and biogas that was already developed in previous research. Just by the addition of an extra chip we extended the applicability of the natural gas sensor to hydrogen admixing. The feasibility of the sensor was demonstrated in our own (TNO) laboratory and at a field test location of the HyDeploy program at Keele University in the U.K

With increasing shares of variable and uncertain renewable generation in many power systems there is an associated increase in the importance of energy storage to help balance supply and demand. Gas networks currently store and transport energy and they have the potential to play a vital role in longer-term renewable energy storage. Gas and electricity networks are becoming more integrated with quick-responding gas-fired power plants providing a significant backup source for renewable electricity in many systems. This study investigates Ireland’s gas network and operation when a variable green hydrogen input from excess wind power is blended with natural gas. How blended hydrogen impacts a gas network’s operational variables is also assessed by modelling a quasi-transient gas flow. The modelling approach incorporates gas density and a compressibility factor in addition to the gas network’s main pressure and flow rate characteristics. With an increasing concentration of green hydrogen up to 20% in the gas network the pipeline flow rate must be increased to compensate for reduced energy quality due to the lower energy density of the blended gas. Pressure drops across the gas pipeline have been investigated using different capacities of P2H from 18 MW to 124 MW. The results show significant potential for the gas network to store and transport renewable energy as hydrogen and improve renewable energy utilisation without upgrading the gas network infrastructure.