United Kingdom

Preliminary research suggests domestic carbon monoxide detectors with an electrochemical sensor are approximately 10 -20% sensitive to hydrogen atmospheres in their factory configuration. That is the display on a carbon monoxide detector would give a carbon monoxide reading of approximately 10-20% of the concentration of hydrogen it is exposed to. Current British standards require detectors to sound an alarm within three minutes when subjected to a continuous concentration of ≥ 300 ppm CO. This would equate to a concentration of 1500-3000 ppm hydrogen in air or approximately 3.75 – 7% %LEL. The current evacuation criteria for a natural gas leak in a domestic property is 20 %LEL indicating that standard carbon monoxide detectors could be used as cheap and reliable early warning systems for hydrogen leaks. Given the wide use of carbon monoxide detectors and the affordability of the devices the use of carbon monoxide detectors for hydrogen detection is of particular interest as the UK drives towards energy decarbonisation. Experiments to determine the exact sensitivity of a range of the most common domestic carbon monoxide detectors have been completed by DNV Spadeadam Research & Testing. Determining the effects of repeated exposure to varying concentrations of hydrogen in air on the sensitivity of electrochemical sensors allows recommendations to be made on their adoption as hydrogen detectors. Changing the catalysts used within the electrochemical cell would improve the sensitivity to hydrogen however simply calibrating the sensor to report a concentration of hydrogen rather than carbon monoxide would represent no additional costs to manufacturers. Having determined the suitability of such sensors at an early stage; the technology can then be linked with other technological developments required for the change to hydrogen for domestic heating (e.g. change in metering equipment and appliances). This report finds that from five simple and widely available carbon monoxide detectors the lowest sensitivity to hydrogen measured at the concentration required to sound an alarm within three minutes was approximately 10%. It was also discovered that as the hydrogen concentration was increased over the range tested the sensitivity to hydrogen also increased. It is proposed that coupling these devices with other elements of the domestic gas system would allow actions such as remote meter isolation or automatic warning signals sent to response services would provide a reliable and inherently safe system for protecting occupants as gas networks transition to net-zero greenhouse gas emissions. In this respect it is noted that wireless linking of smoke and heat detectors for domestic application is already widely available in low-cost devices. This could be extended to CO detectors adapted for hydrogen use.

Electrochemical energy storage is a key enabling technology for further integration of renewables sources. Redox flow batteries(RFBs) are promising candidates for such applications as a result of their durability efficiency and fast response. However deployment of existing RFBs is hindered by the relatively high cost of the (typically vanadium-based) electrolyte. Manganese is an earth-abundant and inexpensive element that is widely used in disposable alkaline batteries. However it has hitherto been little explored for RFBs due to the instability of Mn(III) leading to precipitation of MnO2 via a disproportionation reaction. Here we show that by combining the facile hydrogen negative electrode reaction with electrolytes that suppress Mn(III) disproportionation it is possible to construct a hydrogen/manganese hybrid RFB with high round trip energy efficiency (82%) and high power and energy density (1410 mW cm−2 33 Wh l−1 ) at an estimated 70% cost reduction compared to vanadium redox flow batteries.

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.

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.

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.

The European Marine Energy Centre’s (EMEC) ITEG project (Integrating Tidal Energy into the European Grid) funded by Interreg NWE combines a tidal energy and hydrogen production solution to address grid constraints on the island of Eday in Orkney. The project will install a 0.5MW electrolyser at EMEC’s existing hydrogen production plant. EMEC and Risktec collaboratively applied best practice risk assessment and management techniques to assess and manage hydrogen safety. Hazard identification (HAZID) workshops were conducted collaboratively with design engineers through which a comprehensive hazard register was developed. Risktec applied bowtie analysis to each major accident hazard identified from the hazard register via virtual workshop with design engineers. The bowties promoted a structured review of each hazard’s threat and consequence identifying and reviewing the controls in place against good practice standards. The process revealed some recommendations for further improvement and risk reduction exemplifying a systematic management of risks associated with hydrogen hazards to as low as reasonably practicable (ALARP). Hardware based barriers preventing or mitigating loss of control of these hazards were logged as safety critical elements (SCE) and procedural barriers as safety critical activities (SCA). To ensure that all SCEs and SCAs identified through the risk assessment process are managed throughout the facility’s operational lifetime a safety management system is created giving assurance of overall safety management system continued effectiveness. The process enables the demonstration that design risks are managed to ALARP during design and throughout operational lifetime. More importantly enabling ITEG to progress to construction and operation in 2021.

The Low Carbon Hydrogen Standard sets a maximum threshold for the amount of greenhouse gas emissions allowed in the production process for hydrogen to be considered ‘low carbon hydrogen’. Compliance with the standard will help ensure new low carbon hydrogen production makes a direct contribution to our carbon reduction targets.

This guidance sets out the methodology for calculating the emissions associated with hydrogen production and the steps producers should take to prove that the hydrogen they produce is compliant with the standard.

It is for use by hydrogen producers seeking support from government schemes and policies that have adopted the standard.

The standard requires hydrogen producers to:

• meet a GHG emissions intensity of 20g CO2e/MJLHV of produced hydrogen or less for the hydrogen to be considered low carbon
• calculate their greenhouse gas (GHG) emissions up to the ‘point of production’
• set out a risk mitigation plan for fugitive hydrogen emissions
• meet additional requirements for the use of biogenic inputs where relevant and as appropriate for the feedstock source and classification

A global transition to hydrogen fuel offers major opportunities to decarbonise a range of different energyintensive sectors from large-scale electricity generation through to heating in homes. Hydrogen can be deployed as an energy source in two distinct ways in electrochemical fuel cells and via combustion. Combustion seems likely to be a major pathway given that it requires only incremental technological change. The use of hydrogen is not however without side-effects and the widely claimed benefit that only water is released as a by-product is only accurate when it is used in fuel cells. The burning of hydrogen can lead to the thermal formation of nitrogen oxides (NOx – the sum of NO + NO2) via a mechanism that also applies to the combustion of fossil fuels. NO2 is a key air pollutant that is harmful in its own right and is a precursor to other pollutants of concern such as fine particulate matter and ozone. Minimising NOx as a by-product from hydrogen boilers and engines is possible through control of combustion conditions but this can lead to reduced power output and performance. After-treatment and removal of NOx is possible but this increases cost and complexity in appliances. Combustion applications therefore require optimisation and potentially lower hydrogen-specific emissions standards if the greatest air quality benefits are to derive from a growth in hydrogen use

Across Europe permitted blend levels of hydrogen blending into the gas grid are appreciably higher than that currently permitted in the UK up to 12% mol/mol compared with 0.1% mol/mol. Whilst there is some routine blending undertaking – typically power to gas applications three major projects have been undertaken to demonstrate operation of a gas distribution network at higher blend levels of hydrogen.<br/>A Dutch project was completed in 2011 which demonstrated successful operation into a network with new appliances at 20% mol/mol. A German project was completed in 2015 which demonstrated successful operation into an existing gas network with existing appliances at their permitted level of 10% mol/mol. In France an extensive programme is underway to inject hydrogen into a network at 20% mol/mol due to commence injection in 2018.<br/>Each of these projects undertook extensive pre-trial activities and operational data was collected during the Dutch and German trials. The programme of pre-trial work for the French project was particularly extensive and mirrored the work done by HyDeploy. This led to a permit being granted for the French project at 20% mol/mol with injection into the network imminent.<br/>The HyDeploy team has engaged with each of the project teams who have been very co-operative; this has enabled scientific sharing of best practice. In all cases the projects were successful. The participants in the Dutch project were particularly keen to have been able to undertake a similar trial to HyDeploy; a larger trial into existing appliances. However political changes in Holland have precluded that at this time such progress was not limited by technical findings from the work.<br/>A high level overview of the projects and the data provided is summarised in this report. More detailed information is referenced and covered in more detail where required in the appropriate individual topic reports supporting the Exemption.<br/>Click on supplements tab to view the other documents from this report

This report presents the findings of the initial gap analysis and technical review of IGEM/SR/25 undertaken as a collaborative effort between HSE and DNV GL. The review is intended to help understand the steps which would be involved in updating the standard to include data appropriate for installations using H2 or an H2/NG blend. Furthermore the report highlights where additional research and updated data applicable to H2 installations is needed to enable development of an H2-specific supplement to the standard.<br/>A review of alternative approaches for area classification is presented. This review is aimed at determining whether existing standards or guidance provide methodologies which could be used as an alternative to IGEM/SR/25 for area classification of systems using either H2 or H2/NG blends. The review covers IGEM/SR/25 IGE/SR/23 EI15 BCGA guidance BS EN 60079:10:1 (including Quadvent) NFPA 497 API RP 505 and EIGA Doc. 121/14. Some of these are general like the British Standard BS EN 60079-10-1:2015 while others are industry specific like IGEM/SR/25 and EI15.<br/>Consideration is given to the methodology that each area classification approach presents for establishing the zone and zone size with particular focus on how factors such as ventilation and gas buoyancy are accounted for in the methods. The findings of the review indicate that none of the alternative approaches evaluated in the study provide an approach that is suitable for the gas industry for the area classification of gas network installations involving H2 or an H2/NG blend.