United Kingdom

This is a time of enormous change for the gas industry as the UK and the world at large attempts to meet the challenges of decarbonisation in the face of climate change. Hydrogen is expected to play a vital role in achieving the government’s commitment of eliminating the UK’s contribution to climate change by 2050 with the industry creating up to 8000 jobs by 2030 and potentially unlocking up to 100000 jobs by the middle of the century. But despite the UK government’s huge ambitions hydrogen is just one piece of the puzzle and it will be necessary to seek solutions that bring the whole energy system together – including not just heat for buildings but hard-to decarbonise areas such as manufacturing road transport aviation and shipping. Here we bring you just a taste of some of the amazing work taking place across the energy sector to understand this fuel more clearly to comprehend its strengths and limitations and to integrate it into our current energy infrastructure. We hope you enjoy this special publication.

The term ‘decarbonised gas’ refers to biogases hydrogen and carbon capture utilisation and storage (CCUS). This strategy paper sets out how decarbonised gas can help to get net zero done by tackling the hard-to-decarbonise sectors – industry heavy transport and domestic heating – which together account for around 40% of UK greenhouse gas emissions. It also illustrates the crucial importance of supportive public opinion and sets out in detail how decarbonised gas can help to ensure that net zero is achieved with public support. The report is based on extensive quantitative and qualitative opinion research on climate change in general net zero emissions in the UK and the specific decarbonised gas solutions in homes transport and industry. The full quantitative data is contained in the Supplements tab.<br/><a href="https://www.dgalliance.org/wp-content/uploads/2020/05/DGA-Getting-Net-Zero-Done-final-May-2020.pdf"/><a href="https://www.dgalliance.org/wp-content/uploads/2020/05/DGA-Getting-Net-Zero-Done-final-May-2020.pdf"/>

This paper presents a study undertaken on a naturally aspirated direct injection diesel engine investigating the combustion and emission characteristics of CH₄-CO₂  and CH₄-CO₂ -H₂ mixtures. These aspirated gas mixtures were pilot-ignited by diesel fuel while the engine load was varied between 0 and 7 bar IMEP by only adjusting the flow rate of the aspirated mixtures. The in-cylinder gas composition was also investigated when combusting CH₄-CO₂ and CH₄-CO₂-H₂ mixtures at different engine loads with in cylinder samples collected using two different sampling arrangements. The results showed a longer ignition delay period and lower peak heat release rates when the proportion of CO₂ was increased in the aspirated mixture. Exhaust CO₂ emissions were observed to be higher for 60 CH₄:40CO₂ mixture but lower for the 80CH₄:20CO₂ mixture as compared to diesel fuel only combustion at all engine loads. Both exhaust and in-cylinder NO_x levels were observed to decrease when the proportion of CO₂ was increased; NO_x levels increased when the proportion of H₂ was increased in the aspirated mixture. In-cylinder NO_x levels were observed to be higher in the region between the sprays as compared to within the spray core attributable to higher gas temperatures reached post ignition in that region.

This is the Committee’s fifth report on Scotland’s progress towards meeting emission reduction targets as requested by Scottish Ministers under the Climate Change (Scotland) Act 2009.<br/>The Scottish Act sets a long-term target to reduce emissions of greenhouse gases (GHGs) by at least 80% in 2050 relative to 1990 with an interim target to reduce emissions by 42% in 2020. Secondary legislation passed in October 2010 and October 2011 also set a series of annual emission reduction targets for 2010 to 2022 and 2023 to 2027 respectively. We advised the Scottish Government on annual targets for the period 2028 to 2032 in March 2016 and July 2016.<br/>The report reveals that Scotland’s annual emissions reduction target for 2014 was met with gross Scottish greenhouse gas emissions including international aviation and shipping falling by 8.6% in 2014. This compares to a 7.3% fall for the UK as a whole. Since 1990 gross Scottish emissions have fallen nearly 40% compared to nearly 33% at a UK level.

The Climate Change Committee (CCC) commissioned Element Energy to improve our evidence base on the potential of industrial deep-decarbonisation measures (fuel switching CCS/BECCS measures to reduce methane emissions) and develop pathways for their application. This report summarises the evidence and results of the work including:

• Evidence on the key constraints and costs for technology and infrastructure deployment
• The methodology and new Net Zero Industry Pathway (N-ZIP) model used to determine deep-decarbonisation pathways for UK industry (drawing on the evidence above)
• A set of pathways and wider sensitivities produced using the N-ZIP model which fed into the CCC’s Sixth Carbon Budget pathways
• Recommended actions and policy measures as informed by the study.

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.

As part of the LTS Futures HyTechnical project IGEM requested that DNV GL undertake an assessment of the possible impact of hydrogen transmission on BPDs to support the development of supplements to the existing suite of natural gas standards to accommodate the possible future use of hydrogen. The current state of knowledge of the behaviour of large scale high pressure hydrogen releases is limited in comparison with the considerable body of data from research and operational experience of natural gas but is adequate to undertake an impact assessment to take account of the different gas outflow and fire characteristics of 100% hydrogen vs. natural gas.<br/>Calculations of the BPDs for 100% hydrogen pipeline fires on an equivalent basis to those in IGEM/TD/1 for natural gas have been performed with a degree of confidence in the results and demonstrated that the equivalent BPDs for 100% hydrogen are approximately 10% smaller than for natural gas. The results are presented graphically in this report.<br/>However hydrogen introduces the potential for substantially higher overpressures than natural gas due to the higher flame speed and wider flammable limits if delayed ignition is a credible event. The overpressure estimates presented in this report are intended to be scoping calculations to put the likely overpressures into context. The results suggest that significant overpressures are possible at the BPDs but there is a lack of evidence to support the estimation of the overpressures following delayed ignition of a large turbulent hydrogen release in the open (in contrast to explosions in confined or congested regions) and there is a high degree of uncertainty in the predictions presented here. It is therefore recommended that large scale pipeline rupture experiments are performed similar to those undertaken previously for hydrogen natural gas and natural gas/hydrogen mixtures but with ignition engineered to take place after a short delay in order to measure the overpressures and provide the means to validate or refine the predictions made.<br/>The analysis has highlighted limitations in the original method of calculating BPDs in IGEM/TD/1 which reflects the techniques available at the time approximately 40 years ago. Since then understanding of the hazards from pipeline failures and the ability to model the consequences and predict the associated risks to people in the surrounding area have advanced very considerably facilitated by software tools and documented in standards such as IGEM/TD/2. These methods allow the highly transient nature of a high pressure gas pipeline rupture release to be modelled more accurately and for the thermal effects of fires on people and buildings to be calculated taking account of the time-varying thermal dose.<br/>For these reasons a simple comparison of the possible overpressure effects of delayed ignition of a 100% hydrogen release at the BPDs can be misleading and implies that the overpressure hazards could be more severe than those for fires which may not be the case. Example calculations have been performed for a representative pipeline case which indicate that using current methods the predicted thermal hazard distances for 100% hydrogen pipeline fires (house burning and escape for people) are substantially greater than those estimated for overpressures following delayed ignition for similar levels of vulnerability. This report addresses buried pipelines only – the potential for more severe explosion overpressure effects for hydrogen releases may be more significant for Above Ground Installations (AGIs) especially where congestion or confinement may be present. It is recommended that similar studies are conducted to quantify the effect of hydrogen conversion on the consequences and risks associated with hydrogen releases at AGIs.<br/>Finally it is stressed that the analysis in this report does not consider the relative risks for 100% hydrogen and the equivalent natural gas pipelines. There remain uncertainties in the failure frequencies for steel pipelines transporting hydrogen and particularly the probability of immediate and delayed ignition. The likelihood of delayed ignition of a large turbulent high pressure hydrogen gas pipeline rupture release may be very low due to the wider flammability limits and lower minimum ignition energy for hydrogen compared with natural gas. Additional research is currently ongoing or planned to address the gaps in knowledge for 100% hydrogen which should allow more robust comparisons of the relative risks to be made in the future.

This is the Committee’s 2020 report to Parliament assessing progress in reducing UK emissions over the past year. This year the report includes new advice to the UK Government on securing a green and resilient recovery following the COVID-19 pandemic. The Committee’s new analysis expands on its May 2020 advice to the UK Prime Minister in which it set out the principles for building a resilient recovery. In its new report the Committee has assessed a wide set of measures and gathered the latest evidence on the role of climate policies in the economic recovery. Its report highlights five clear investment priorities in the months ahead:

• Low-carbon retrofits and buildings that are fit for the future
• Tree planting peatland restoration and green infrastructure
• Energy networks must be strengthened
• Infrastructure to make it easy for people to walk cycle and work remotely
• Moving towards a circular economy.

There are also opportunities to support the transition and the recovery by investing in the UK’s workforce and in lower-carbon behaviours and innovation:

• Reskilling and retraining programmes
• Leading a move towards positive behaviours
• Targeted science and innovation funding

The Paris Agreement marks a significant positive step in global action to tackle climate change. This report considers the domestic actions the UK Government should take as part of a fair contribution to the aims of the Agreement.<br/>The report concludes that the Paris Agreement is a significant step forward in global efforts to tackle climate change. It is more ambitious in its aims to limit climate change than the basis of the UK’s existing climate targets. However it is not yet appropriate to set new UK targets. Existing targets are already stretching and the priority is to take action to meet them.

This White Paper has been commissioned by the UK Hydrogen and Fuel Cell (H2FC) SUPERGEN Hub to examine the roles and potential benefits of hydrogen and fuel cell technologies for heat provision in future low-carbon energy systems. The H2FC SUPERGEN Hub is an inclusive network encompassing the entire UK hydrogen and fuel cells research community with around 100 UK-based academics supported by key stakeholders from industry and government. It is funded by the UK EPSRC research council as part of the RCUK Energy Programme. This paper is the first of four that will be published over the lifetime of the Hub with the others examining: (i) low-carbon energy systems (including balancing renewable intermittency); (ii) low-carbon transport systems; and (iii) the provision of secure and affordable energy supplies for the future

• Hydrogen and fuel cells are part of the cost-optimal heating technology portfolio in long-term UK energy system scenarios.
• Fuel cell CHP is already being deployed commercially around the world.
• Hydrogen can be a zero-carbon alternative to natural gas. Most technologies that use natural gas can be adapted to use hydrogen and still provide the same level of service.
• Hydrogen and fuel cell technologies avoid some of the disadvantages of other low-carbon heating technologies.