Hydrogen Blending

The report analyses the technical impacts to end-users of natural gas in Australian distribution networks when up to 10% hydrogen (by volume) is mixed with natural gas.



The full report can be found at this link.

"Hydrogen is expected to play a critical role in the move to a net-zero economy. However large-scale deployment is still in its infancy and there is still much to be done before we can blend hydrogen in large volumes into gas networks and ramp up the production that is required to meet demands of the energy transport and industry sectors. KTN Global Alliance will host two webinars to explore these challenges and opportunities in hydrogen blending on the 2nd and 3rd March 2021.



Exciting pilot projects are being conducted and explored in the UK Canada and US states such as California to determine the technical feasibility of blending hydrogen into existing natural gas systems. Whilst the deployment of hydrogen is in its early stages there is increasing interest around permitting significant percentage blends of hydrogen into gas networks which would enable the carbon intensity of gas supplies to be reduced creating a new demand for hydrogen and with the use of separation and purification technologies downstream support the transportation of pure hydrogen to markets.

Gaps in codes and standards need to be addressed to enable adoption and there may be opportunities for international collaboration and harmonisation to ensure that best practices are shared globally and to facilitate the growth of trade and export markets. There is an opportunity for the UK Canada and US three G7 countries to work together and show market making leadership in key enabling regulation for the new hydrogen economy.



Delivered by KTN Global Alliance on behalf of the British Consulate-General in Vancouver and the UK Science and Innovation Network in Canada and the US these two webinars will showcase hydrogen blending pilot projects in the UK Canada and California highlighting challenges and opportunities with regard to standards development for hydrogen blending and supporting further transatlantic collaboration in this area. The events also form part of the UK’s international engagement to build momentum towards a successful outcome at COP26 the UN climate summit that the UK will host in Glasgow in November 2021. The webinars will bring together experts from industry academia and policy from the UK Canada and California. Attendees will have an opportunity to ask questions and interact using Mentimeter."











Part 2 Highlights and Perspectives from Canada and California can be found here.

Hydrogen is expected to play a critical role in the move to a net-zero economy. However large-scale deployment is still in its infancy and there is still much to be done before we can blend hydrogen in large volumes into gas networks and ramp up the production that is required to meet demands of the energy transport and industry sectors. KTN Global Alliance will host two webinars to explore these challenges and opportunities in hydrogen blending on the 2nd and 3rd March 2021.



Exciting pilot projects are being conducted and explored in the UK Canada and US states such as California to determine the technical feasibility of blending hydrogen into existing natural gas systems. Whilst the deployment of hydrogen is in its early stages there is increasing interest around permitting significant percentage blends of hydrogen into gas networks which would enable the carbon intensity of gas supplies to be reduced creating a new demand for hydrogen and with the use of separation and purification technologies downstream support the transportation of pure hydrogen to markets.

Gaps in codes and standards need to be addressed to enable adoption and there may be opportunities for international collaboration and harmonisation to ensure that best practices are shared globally and to facilitate the growth of trade and export markets. There is an opportunity for the UK Canada and US three G7 countries to work together and show market making leadership in key enabling regulation for the new hydrogen economy.



Delivered by KTN Global Alliance on behalf of the British Consulate-General in Vancouver and the UK Science and Innovation Network in Canada and the US these two webinars will showcase hydrogen blending pilot projects in the UK Canada and California highlighting challenges and opportunities with regard to standards development for hydrogen blending and supporting further transatlantic collaboration in this area. The events also form part of the UK’s international engagement to build momentum towards a successful outcome at COP26 the UN climate summit that the UK will host in Glasgow in November 2021. The webinars will bring together experts from industry academia and policy from the UK Canada and California. Attendees will have an opportunity to ask questions and interact using Mentimeter.











Part 1 Highlights and Perspectives from the UK can be found here.

DNV has carried out an investigation into potential uses for smart gas meter data as part of Phase 1 of the Modernising Energy Data Applications competition as funded by UK Research & Innovation. In particular a series of calculations have been carried out to investigate the possibility of differentiating accidental gas leaks from normal appliance use in domestic properties. This is primarily with the aim of preventing explosions but the detection of leaks also has environmental and financial benefits.

Three gases have been considered in this study:

• A representative UK natural gas composition.
• A blend of 80% natural gas and 20% hydrogen.
• Pure hydrogen.

An established method was used to calculate the gas outflow rate from leaks into buildings downstream of the meter regulator. These gas leak rates were compared with the gas use by typical domestic appliances and these leaks were considered in the context of the smart gas meter data that is currently available in 30-minute periods. A representative set of gas accumulation calculations was performed. It was found that the following three general cases apply to all three gases:

• Small holes of up to 1 mm rarely reach flammable gas/air concentrations for any gas except under the most unfavourable conditions such as small volumes combined with low ventilation rates. These releases would likely be detected within 6 to 12 hours.
• Medium holes between 1 mm and 6 mm give outflow rates equivalent to a moderate to high level of gas use by appliances. The ability to detect these leaks is highly dependent on the hole size the time at which the leak begins and the normal gas use profile in the building. The larger leaks in this category would be detected within 30 to 60 minutes while the smaller leaks could take several hours to be clearly differentiated from appliance use. This is quick enough to prevent some explosions.
• Large holes of over 6 mm give leak rates greater than any gas use by appliances. These releases rapidly reach a flammable gas/air mixture in most cases but would typically be detected within the first 30-minute meter output period. Again some explosions could be prevented in this timescale.

An event tree has been used to quantify the approximate success rate of detecting and preventing explosion events. Using the currently available 30-minute smart meter data and functionality it is estimated that around 7% of explosions could be prevented with a slight variation depending on the gas type in use. Additional functionality could be included in the meter to improve this performance. Typically one of the risk mitigation measures in isolation increases the explosion prevention rate to around 15%. If multiple improvements are made then the detection rate is predicted to increase to around 30%.

An examination of detailed historical incident information suggests that the explosions that lead to fatalities or significant damage to houses are typically of the type that would be more likely to be detected and prevented. It is estimated that between 25% and 75% of the more severe explosions could be prevented depending on which potential improvements are implemented.

Based on the conservative estimates of explosion prevention a cost benefit analysis suggests that it is justifiable to spend between around £1 and £10 per meter installed to implement the proposed technology. This is based purely on lives saved and does not take account of other benefits.

To meet the target of reducing greenhouse gas emissions hydrogen as a carbon-free fuel is expected to play a major role in future energy supplies. A challenge with hydrogen is its low density and volumetric energy value meaning that large tanks are needed to store and transport it. By injecting hydrogen into the natural gas network the transportation issue could be solved if the hydrogen–natural gas mixture satisfies the grid gas quality requirements set by legislation and standards. The end consumers usually have stricter limitations on the gas quality than the grid where Euromot the European association of internal combustion engine manufacturers has specific requirements on the parameters: the methane number and Wobbe index. This paper analyses how much hydrogen can be added into the natural gas grid to fulfil Euromot’s requirements. An average gas composition was calculated based on the most common ones in Europe in 2021 and the results show that 13.4% hydrogen can be mixed with a gas consisting of 95.1% methane 3.2% ethane 0.7% propane 0.3% butane 0.3% carbon dioxide and 0.5% nitrogen. The suggested gas composition indicates for engine manufacturers how much hydrogen can be added into the gas to be suitable for their engines.

Hydrogen production from renewable energy is gaining increasing attention to enhance energy consumption structure and foster a more eco-friendly and sustainable society. At the same time mixing hydrogen with natural gas and supplying it to civilians is one of the best ways to reduce carbon emissions and increase the reliability of technology while reducing the costs of storing and transporting hydrogen. Even though numerous researchers have conducted experimental and simulation studies on hydrogen-doped natural gas most of these studies have focused on the effects of hydrogen-doped ratio equivalence ratio and fuel combustion mode. The impact of burner structure on hydrogen-enriched natural gas has not received much attention. Compared with conventional direct-flow combustion swirl combustion can improve the mixing effect of the fuel mixture during combustion and the use of regions of reversed flow due to swirl can make the fuel burn more fully to achieve the reduction of pollutant emissions. Swirling flames are widely used in gas turbines and industrial furnaces because of their high stability. However the application of swirl combustion in domestic equipment is still in its infancy which deserves more researchers to explore and enhance the working conditions of domestic combustion equipment. In this paper a three-dimensional swirl burner model is utilized to examine the effect of swirl angle θ and swirl length L of the swirler on the combustion behavior of hydrogen-enriched natural gas in a swirl burner. The results indicate that the swirl angle θ and swirl length L play an essential role in the combustion of natural gas containing hydrogen. As the swirl angle θ increases the flame temperature decreases more slowly the combustion becomes more stable and the length of the flame is slightly increased. Simultaneously CO and NO emissions will gradually decrease and the combustion effect is enhanced when the swirl angle is 45◦. With increased swirl length L the flame length grows the high-temperature region expands and CO and NO emissions decrease. Meanwhile the change in swirl length has little effect on the increase of flame peak temperature when the fuel is thoroughly mixed. When the swirl length is 12 mm CO and NO emissions are lower and NO emissions are reduced by 36.11% compared to a swirl length of 6 mm. This work is a reference point for applying hydrogen-mixed natural gas in the swirl burner but it must be studied and optimized further in future research.

To reduce greenhouse gas emissions from natural gas use utilities are investigating the potential of adding hydrogen to their distribution grids. This will reduce the carbon dioxide emissions from grid-connected engines used for stationary power generation and it may also impact their power output and efficiency. Promisingly hydrogen and natural gas mixtures have shown encouraging results regarding engine power output pollutant emissions and thermal efficiency in well-controlled on-road vehicle applications. This work investigates the effects of adding hydrogen to the natural gas fuel for a lean-burn spark-ignited four-stroke 8.9 liter eight-cylinder naturally aspirated engine used in a commercial stationary power generation application via an engine model developed in the GT-SUITETM modelling environment. The model was validated for fuel consumption air flow and exhaust temperature at two operating modes. The focus of the work was to assess the sensitivity of the engine’s power output brake thermal efficiency and pollutant emissions to blends of methane with 0–30% (by volume) hydrogen. Without adjusting for the change in fuel energy the engine power output dropped by approximately 23% when methane was mixed with 30% by volume hydrogen. It was found that increasing the fueling rate to maintain a constant equivalence ratio prevented this drop in power and reduced carbon dioxide emissions by almost 4.5%. In addition optimizing the spark timing could partially offset the increases in in-cylinder burned and unburned gas temperatures and in-cylinder pressures that resulted from the faster combustion rates when hydrogen was added to the natural gas. Understanding the effect of fuel change in existing systems can provide insight on utilizing hydrogen and natural gas mixtures as the primary fuel without the need for major changes in the engine.

To study the effect of hydrogen-blended natural gas on the combustion stability and emission of domestic gas water heater a test system is built in this paper taking a unit of the partial premixed burner commonly used in water heaters as the object. Under the heat load of 0.7~2.3kW the changes of flame shape burner temperature and pollutant emission of natural gas with hydrogen volume ratio of 0~40% are studied with independent control of primary air supply and mixing. The results show that: with the increase of hydrogen blending ratio the inner flame height increases firstly and then reduces while the change of burner temperature is opposite. The maximum inner flame height and the minimum temperature of the burner both appear at the hydrogen blending ratio of 10~20%. It can be seen that the limit of hydrogen blending ratio which can maintain the burner operate safely and stably under rated heat load is 40% through the maximum temperature distribution on the burner surface. The CO emission in the flue gas gradually decreases with the increase of hydrogen blending ratio while the NOx emission fluctuates slightly when the hydrogen blending ratio is less than 20% but then decreases gradually.

The THyGA project (‘Testing Hydrogen admixture for Gas Applications’) focusses on technical aspects and the regulatory framework concerning the potential operation of domestic and commercial end-user appliances with hydrogen / natural gas blends.<br/>The core of the project is a broad experimental campaign with the aim to conduct up to 100 hydrogen tolerance tests. In addition the technical status quo and present knowledge about hydrogen impact on domestic and commercial appliances are assessed and potential future developments of rules and standards are discussed. Also mitigation strategies for coping with high levels of hydrogen admixture will be developed. By this broad approach the project aims at investigating which levels of hydrogen blending impact the various appliance technologies and to which extent in order to identify the regime in which a safe efficient and low-polluting operation is possible.<br/>The series of public reports by the THyGA project starts with several publications from work package 2 which sets the basis for the upcoming results and discussion of the experimental campaign as well as mitigation and standardisation topics.<br/>This report D2.5 completes the series of public reports from work package 2. It explains the steps of development of the test programme for gas-fired appliance tests with hydrogen admixture and especially describes the exchange between the THyGA partners and the external stakeholders.<br/>The report also explains the process of acquisition of appliances to test and method of selecting appliances.

Biogas is a renewable gas with low heat energy which makes it extremely difficult to use as fuel in conventional natural gas equipment. Nonetheless the use of hydrogen as a biogas additive has proven to have a beneficial effect on flame stability and combustion behavior. This study evaluates the biogas–hydrogen combustion in a conventional natural gas burner able to work up to 100 kW. Tests were performed for three different compositions of biogas: BG70 (30% CO₂) BG60 (40% CO₂) and BG50 (50% CO₂). To achieve better flame stability each biogas was enriched with hydrogen from 5% to 25%. The difficulty of burning biogas in conventional systems was proven as the burner does not ignite when the biogas composition contains more than 40% of CO₂. The best improvements were obtained at 5% hydrogen composition since the exhaust gas temperature and thus the enthalpy rises by 80% for BG70 and 65% for BG60. The stability map reveals that pure biogas combustion is unstable in BG70 and BG60; when the CO₂ content is 50% ignition is inhibited. The properties change slightly when the hydrogen concentrations are more than 20% in the fuel gas and do not necessarily improve.