United Kingdom

Unignited hydrogen release in underground parking could be considered inherently safer if the safety strategy to avoid the formation of the flammable hydrogen-air mixture under a ceiling is followed. This strategy excludes destructive deflagrative combustion and associated pressure and thermal effects in the case of ignition. This paper aims at understanding the effects of the thermally activated pressure relieve device (TPRD) diameter and direction of release on the build-up of hydrogen flammable concentration under the ceiling in the presence of mechanical ventilation required for underground parking. The study employs the similarity law for hydrogen jet concentration decay in a free under-expanded jet to find the lower limit of TPRD diameter that excludes the formation of a flammable mixture under the ceiling during upward release. This approach is conservative and does not include the effect of mechanical ventilation providing flow velocity around a few meters per second which is significantly below velocities in hydrogen momentum-dominated under-expanded jets. Hydrogen releases downwards under a vehicle at different angles and with different air velocities due to mechanical ventilation were investigated using computational fluid dynamics (CFD). The joint effect of TPRD diameter release direction and mechanical ventilation is studied. TPRD diameters for the release of hydrogen upwards and downwards preventing the creation of flammable hydrogen-air mixture under the parking ceiling are defined for different ceiling heights and locations of TPRD above the floor. Recommendations to the design of TPRD devices to underpin the safe introduction of hydrogen fuelled vehicles in currently existing underground parking and infrastructure are formulated."

The demand for hydrogen has grown more than threefold since 1975 [1] and price is expected to significantly decrease by 2030 [2] concluding in an expected continual increase in demand. HyLaw defined by Hydrogen Europe lays out recommendations for hydrogen applications using identified Legal and Administrative Processes (LAPs) across 18 European countries. Regarding site location HyLaw refers to the land use plan. This defines the production and storage of hydrogen as an industrial activity and therefore regardless of the specific site methods of production or use the hydrogen site must be within a permitted industrial zone or under specific condition commercial areas [3]. Local authorities fire departments and other concerned parties may need to be consulted on site suitability for the project. Risktec explores a range of considerations for siting and layout of hydrogen developments including co-location with other assets for example with renewable energy sources hazardous facilities or public structures. Good practice tools and assessment techniques are presented to mitigate the risks associated with the production storage and use of hydrogen not just the surrounding site and environment but the operatives of the facility.

Dilution ventilation is the current basis of safety following a flammable gas leak within a gas turbine enclosure and compliance requirements are defined for methane fuels in ISO 21789. These requirements currently define a safety criteria of a maximum flammable gas cloud size within an enclosure. The requirements are based on methane explosion tests conducted during a HSE Joint Industry Project which identified typical pressures associated with a range of gas cloud sizes. The industry standard approach is to assess the ventilation performance of specific enclosure designs against these requirements using CFD modelling. Gas turbine manufacturers are increasingly considering introducing hydrogen/methane fuel mixtures and looking towards operating with hydrogen alone. It is therefore important to review the applicability of current safety standards for these new fuels as the pressure resulting from a hydrogen explosion is expected to be significantly higher than that from a methane explosion. In this paper we replicate the previous methane explosion tests for hydrogen and hydrogen/methane fuel mixtures using the explosion modelling tool FLACS CFD. The results are used to propose updated limiting safety criteria for hydrogen fuels to support ventilation CFD analysis for specific enclosure designs. It is found that significantly smaller gas cloud sizes are likely to be acceptable for gas turbines fueled by hydrogen however significantly more hydrogen than methane is required per unit volume to generate a stoichiometric cloud (as hydrogen has a lower stoichiometric air fuel ratio than methane). This effect results in the total quantity of gas in the enclosure (and as such detectability of the gas) being broadly similar when operating gas turbines on hydrogen when compared to methane.

This independent cross-party report highlights the key role that political consensus can play in helping to reduce the costs of nuclear power in the UK as well as other low carbon technologies. This political consensus has never been more important than in this ‘defining decade’ for the power sector. The report highlights that an immediate challenge facing the UK’s new build programme is agreeing with the European Commission a regime for supporting new nuclear power. Changing the proposed support package would not be an impossible task if made necessary but maintaining broad political consensus and considering the implications of delay are also important. The State Aid process is an important opportunity for scrutiny with the report demonstrating that shareholders for Hinkley Point C could see bigger returns (19-21%) than those typically expected for PFI projects (12-15%). However it is too early to conclude on the value for money of the Hinkley Point C agreement. Both the negotiation process and the resulting investment contract are important but there has been little transparency over either so far and the negotiations were not competitive. The inquiry calls for more urgency and better coordination in seizing the opportunity to reuse the UK’s plutonium stockpile.



The UK’s stockpile of separated plutonium presents opportunities to tackle a number of national strategic priorities including implementing long term solutions for nuclear waste developing new technologies that could redefine the sector laying the ground for new nuclear power and pursuing nuclear non-proliferation.  Government has identified three ‘credible solutions’ for reuse and the report recommends that it now sets clearer criteria against which to assess options and identifies budgetary requirements to help expediate the process. The report also argues that Government should do more on new nuclear technologies that could redefine the sector – such as considering smaller reactors nuclear for industrial heat or hydrogen production and closed or thorium fuel cycles. The Government’s initial response to a review of nuclear R&D a year ago by the then Chief Scientific Advisor Sir John Beddington has been welcome and it needs to build on this. In particular the UK should capitalise upon its existing expertise and past experience to focus efforts where there is most strategic value. Nulcear waste. Having failed to date the Government must urgently revisit plans for finding a site to store nuclear waste underground for thousands of years. Implementing this is a crucial part of demonstrating that nuclear waste is a manageable challenge. Despite being rejected by Cumbria County Council the continuing strong support amongst communities in West Cumbria for hosting a site is a promising sign.



On affordability the report finds that it is not yet clear which electricity generation technologies will be cheapest in the 2020s and beyond. Coal and gas could get more expensive if fossil fuel and carbon prices rise whilst low carbon technologies could get cheaper as technology costs fall with more deployment. This is the main reason for adopting an ‘all of the above’ strategy including nuclear power until costs become clearer and there is broad consensus behind this general approach.  



On security of supply the inquiry says that deployment of nuclear power is likely to be influenced more by the economics of system balancing rather than technical system balancing challenges which can be met with greater deployment of existing balancing tools. The cost of maintaining system security is likely to mean that the UK maintains at least some baseload capacity such as nuclear power to limit system costs.



On sustainability the report finds that the environmental impacts of nuclear power are comparable to some generation technologies and favourable to others although the long lived nature of some radioactive nuclear waste and the dual use potential of nuclear technology for civil and military applications create unique sustainability challenges which the UK is a world leader in managing.



It is the final report of the Future Electricity Series an independent and cross party inquiry into the UK power sector sponsored by the Institution of Gas Engineers and Managers

Transporting green hydrogen by existing natural gas networks has become a practical means to accommodate curtailed wind and solar power. Restricted by pipe materials and pressure levels there is an upper limit on the hydrogen blending ratio of hydrogen-enriched compressed natural gas (HCNG) that can be transported by natural gas pipelines which affects whether the natural gas network can supply energy safely and reliably. To this end this paper investigates the effects of the intermittent and fluctuating green hydrogen produced by different types of renewable energy on the dynamic distribution of hydrogen concentration after it is blended into natural gas pipelines. Based on the isothermal steady-state simulation results of the natural gas network two convection–diffusion models for the dynamic simulation of hydrogen injections are proposed. Finally the dynamic changes of hydrogen concentration in the pipelines under scenarios of multiple green hydrogen types and multiple injection nodes are simulated on a seven-node natural gas network. The simulation results indicate that compared with the solar-power-dominated hydrogen productionblending scenario the hydrogen concentrations in the natural gas pipelines are more uniformly distributed in the wind-power-dominated scenario and the solar–wind power balance scenario. To be specific in the solar-power-dominated scenario the hydrogen concentration exceeds the limit for more time whilst the overall hydrogen production is low and the local hydrogen concentration in the natural gas network exceeds the limit for nearly 50% of the time in a day. By comparison in the wind-power-dominated scenario all pipelines can work under safe conditions. The hydrogen concentration overrun time in the solar–wind power balance scenario is also improved compared with the solar-power-dominated scenario and the limit-exceeding time of the hydrogen concentration in Pipe 5 and Pipe 6 is reduced to 91.24% and 91.99% of the solar-power-dominated scenario. This work can help verify the day-ahead scheduling strategy of the electricity-HCNG integrated energy system (IES) and provide a reference for the design of local hydrogen production-blending systems.

The geological storage of hydrogen is necessary to enable the successful transition to a hydrogen economy and achieve net-zero emissions targets. Comprehensive investigations must be undertaken for each storage site to ensure their long-term suitability and functionality. As such the systematic infrastructure and potential risks of large-scale hydrogen storage must be established. Herein we conducted over 250 batch reaction experiments with different types of reservoir sandstones under conditions representative of the subsurface reflecting expected time scales for geological hydrogen storage to investigate potential reactions involving hydrogen. Each hydrogen experiment was paired with a hydrogen-free control under otherwise identical conditions to ensure that any observed reactions were due to the presence of hydrogen. The results conclusively reveal that there is no risk of hydrogen loss or reservoir integrity degradation due to abiotic geochemical reactions in sandstone reservoirs.

The UK’s first-ever Hydrogen Strategy drives forward the commitments laid out in the Prime Minister’s ambitious 10 Point Plan for a green industrial revolution by setting the foundation for how the UK government will work with industry to meet its ambition for 5GW of low carbon hydrogen production capacity by 2030 – the equivalent of replacing natural gas in powering around 3 million UK homes each year as well as powering transport and businesses particularly heavy industry.<br/>A booming UK-wide hydrogen economy could be worth £900 million and create over 9000 high-quality jobs by 2030 potentially rising to 100000 jobs and worth up to £13 billion by 2050. By 2030 hydrogen could play an important role in decarbonising polluting energy-intensive industries like chemicals oil refineries power and heavy transport like shipping HGV lorries and trains by helping these sectors move away from fossil fuels. Low-carbon hydrogen provides opportunities for UK companies and workers across our industrial heartlands.<br/>With government analysis suggesting that 20-35% of the UK’s energy consumption by 2050 could be hydrogen-based this new energy source could be critical to meet our targets of net zero emissions by 2050 and cutting emissions by 78% by 2035 – a view shared by the UK’s independent Climate Change Committee. In the UK a low-carbon hydrogen economy could deliver emissions savings equivalent to the carbon captured by 700 million trees by 2032 and is a key pillar of capitalising on cleaner energy sources as the UK moves away from fossil fuels.

In this study a green hydrogen system was studied to provide electricity for an office building in the Sharjah emirate in the United Arab Emirates. Using a solar PV a fuel cell a diesel generator and battery energy storage; a hybrid green hydrogen energy system was compared to a standard hybrid system (Solar PV a diesel generator and battery energy storage). The results show that both systems adequately provided the power needed for the load of the office building. The cost of the energy for both the basic and green hydrogen energy systems was 0.305 USD/kWh and 0.313 USD/kWh respectively. The cost of the energy for both systems is very similar even though the capital cost of the green hydrogen energy system was the highest value; however the replacement and operational costs of the basic system were higher in comparison to the green hydrogen energy system. Moreover the impact of the basic system in terms of the carbon footprint was more significant when compared with the green hydrogen system. The reduction in carbon dioxide was a 4.6 ratio when compared with the basic system.

Combined heat and power (CHP) systems offer high energy efficiencies as they utilise both the electricity generated and any excess heat by co-suppling to local consumers. This work presents the potential of a combined heat and hydrogen (CHH) system a solution where Proton exchange membrane (PEM) electrolysis systems producing hydrogen at 60–70% efficiency also co-supply the excess heat to local heat networks. This work investigates the method of capture and utilisation of the excess heat from electrolysis. The analysed system was able to capture 312 kW of thermal energy per MW of electricity and can deliver it as heated water at either 75 ◦C or 45 ◦C this appropriate for existing district heat networks and lower temperature heat networks respectively. This yields an overall CHH system efficiency of 94.6%. An economic analysis was conducted based on income generated through revenue sales of both hydrogen and heat which resulted in a significant reduction in the Levelized Cost of Hydrogen.

Fuel transition can decarbonize shipping and help meet IMO 2050 goals. In this paper HFO with CCS LNG with CCS bio-methanol biodiesel hydrogen ammonia and electricity were studied using empirical ship design models from a fleet-level perspective and at the Tank-ToWake level to assist operators technology developers and policy makers. The cargo attainment rate CAR (i.e. cargo that must be displaced due to the low-C propulsion system) the ES (i.e. TTW energy needed per ton*n.m.) the CS (economic cost per ton*n.m.) and the carbon intensity index CII (gCO2 per ton*n.m.) were calculated so that the potential of the various alternatives can be compared quantitatively as a function of different criteria. The sensitivity of CAR towards ship type fuel type cargo type and voyage distance were investigated. All ship types had similar CAR estimates which implies that considerations concerning fuel transition apply equally to all ships (cargo containership tankers). Cargo type was the most sensitive factor that made a ship either weight or volume critical indirectly impacting on the CAR of different fuels; for example a hydrogen ship is weight-critical and has 2.3% higher CAR than the reference HFO ship at 20000 nm. Voyage distance and fuel type could result in up to 48.51% and 11.75% of CAR reduction. In addition to CAR the ES CS and CII for a typical mission were calculated and it was found that HFO and LNG with CCS gave about 20% higher ES and CS than HFO and biodiesel had twice the cost while ammonia methanol and hydrogen had 3–4 times the CS of HFO and electricity about 20 times suggesting that decarbonisation of the world’s fleet will come at a large cost. As an example of including all factors in an effort to create a normalized scoring system an equal weight was allocated to each index (CAR ES CS and CII). Biodiesel achieved the highest score (80%) and was identified as the alternative with the highest potential for a deep-seagoing containership followed by ammonia hydrogen bio-methanol and CCS. Electricity has the lowest normalized score of 33%. A total of 100% CAR is achievable by all alternative fuels but with compromises in voyage distance or with refuelling. For example a battery containership carrying an equal amount of cargo as an HFO-fuelled containership can only complete 13% of the voyage distance or needs refuelling seven times to complete 10000 n.m. The results can guide decarbonization strategies at the fleet level and can help optimise emissions as a function of specific missions.