Impact case study database

Impact on industry (1): assisting hazard analysis and the development of mitigating measures to improve safety in hydrogen energy applications

As a zero-emissions fuel that is seen as a viable alternative to fossil fuels, hydrogen has been identified in the European Strategic Energy Technology Plan as having an important role to play in achieving a 60~80% reduction in greenhouse gases by 2050. Yet while it is inherently safer as well as more environmentally sound than other fuels, it has a wider flammability range. Hydrogen gas is odourless and pure hydrogen flames are invisible. Explosions - thankfully rare - can cause damage to facilities and/or surrounding properties, as well as injury or loss of life. A recent example includes damage of 60 homes in an explosion at a hydrogen fuel cell plant in California [5.1a], with a vast emergency services response often required in these circumstances. The average cost of a hydrogen facility incident in monetary terms has been estimated at around USD33,000,000 [5.1b].

Between 2016 and 2020 Professor Wen and her team worked with a range of global companies who are leaders in gas technology, applying Warwick FIRE’s research to safety-critical scenarios across several industrial sectors, including energy, built environment and transport. These forward-planning strategies have at their heart the health and safety of employees and any others who might find themselves in the vicinity of a leak or explosion, but they also serve to foster confidence between companies, authorities and the public. Commercial benefits such as improved sales and cost savings have also been achieved in some cases.

Air Liquide S.A. is a French multinational company which supplies industrial gases and services to industries including medical, chemical and electronic manufacturers. It employs 50,000 staff across 80 countries and serves more than 2,000,000 customers and patients. The company is increasingly focusing on cryogenic liquid hydrogen (CryoLH2) as a storage medium in fuelling stations as its high density renders storage of large quantities possible in compact facilities. However, there are safety concerns related to accidental release of CryoLH2, which is typically −252.87°C and below the freezing temperature of oxygen (O₂) (-218.8°C). In addition, it evaporates with a volume expansion of 1:848, posing significant risk as a highly flammable gas [5.2] with a concomitant risk of suffocation in enclosed spaces. Between November 2019 and March 2020 Wen’s team conducted CFD predictions of potential accidental releases from cryogenic tanks to assess the mitigation effects of retention pools in limiting the size of the dispersed hydrogen cloud. The predictions have enabled Air Liquide to establish internal rules about the compulsory requirements for retention pools and their recommended sizes according to the dimensions of the CryoLH2 storage tanks in different facilities. “ This has considerable impact on the safe operation of our worldwide hydrogen business,” says the Lead Engineer of Process Safety at Air Liquide. [5.2].

Bureau Veritas specialises in testing, inspection and certification across in a variety of sectors, from building and infrastructure through agri-food and commodities to marine and offshore, in over 140 countries. Between 2019 and early 2020, Service Risques Industriels of Bureau Veritas Exploitation used Warwick FIRE’s engineering model (EM) for a hydrogen station case study to evaluate the maximum overpressure level in a container filled with hydrogen at high pressure. “ This constituted a vulnerability study to ensure customer safety… the EM correlation will be incorporated into our programme of risk studies for hydrogen and biogas going forward,” stated the Process Safety Engineer of Service Risques Industriels. [5.3].

Shell India Markets Private Ltd “ plans to apply HyFOAM code in design analysis and facility siting to model large-scale hydrogen explosions in storage centres, hydrogen or/and multi-fuel refuelling stations,” says Shell India Markets’ Technical Safety Engineer. Following the collaboration on the development of HyFOAM between 2016 and 2019, Shell have supplied Warwick FIRE with the in-house developed PDRFOAM, which will enable Professor Wen’s group to extend its modelling to deal with more complex geometries. [5.4].

Impact on industry (2): Reducing the cost in developing fire protection measures and conducting quantified risk analysis for the petrochemical industry

FM Global is a US-based international insurance company that specializes in loss prevention services in the Highly Protected Risk property insurance market sector. It has used the improved FireFOAM models within the company to evaluate fire risk and suppression methods to enhance practical fire protection measures. The Group Manager Fire Dynamics, says: “ The model and numerical tool that Warwick’s research team contributed to develop has enabled our researchers and engineers to better understand heat transfer and fire dynamics, and to conduct technically robust engineering evaluation and design in a cost-effective manner.” [5.5] The application of the new tool has significantly reduced the number of costly large-scale fire tests (around USD100,000 (02-2020) each) and minimized the turnover time for engineering problem-solving. The code has been released by FM Global for free downloading by worldwide industry and academia for fire protection analysis [5.6]. The company has been using the improved model since 2018; and coupled it with a physics-based model for radiation attenuation by watermist which they developed internally.

Det Norske Veritas (DNV GL) is an international accredited registrar and classification society, headquartered in Norway, which between 2014 and 2016 collaborated in a Knowledge Transfer Partnership (KTP) with Professor Wen. The KTP “ provided an important contribution to strengthen some of [DNV’s] services… [which] relate to the risk assessment and advanced modelling of major hazardous scenarios in oil and gas installations,” according to the partner’s final report. [5.7] The KTP led to an enhancement of the predictive accuracy of some specific modelling tools. DNV used the simplified geometric treatment in simulating gas dispersions on offshore oil platforms, floating production systems and process plants in their consultancy services for the oil and gas industry. This resulted in an increase of GBP400,000 in annual sales turnover (predicted to grow to GBP2,000,000 after three years) [5.7], with a pre-tax profit of GBP100,000 in 2016.

Impact on policy makers: setting international standards, informing government policies

Hydrogen is expected to play an important role in helping to decrease carbon emissions as governments around the world set ambitious targets to avoid the most severe consequences of climate change. The EU has proposed to cut greenhouse gas emissions by at least 55% by 2030 in an effort to be  climate neutral by 2050. China has come under international and domestic pressure to reduce its carbon footprint – the world’s largest since 2004 – and in September 2020 President Xi Jinping pledged to stop releasing carbon emissions by 2060. The UK Government’s 10-point green plan [5.8], includes “ [boosting] hydrogen production, with the promise of a town heated entirely by hydrogen by the end of the decade.” Professor Wen’s simplified engineering models (EM) and CFD techniques have been used in governments' planning from a safety perspective and for instigating risk mitigation measures as they scale-up hydrogen energy applications.

The European Committee for Standardisation (CEN) brings together national standardisation bodies of 34 countries to develop European and other technical standards. CEN/TC305 is the technical committee (TC) responsible for Potentially Explosive Atmospheres - Explosion Prevention and Protection, and CEN/TC305/WG3 is the working group (WG) for Devices and Systems for Explosion Prevention and Protection.

The CEN/TC305/WG3/ahGE meeting in Vienna on 14-15 June 2019 decided to include the EM, based on semi-empirical correlations developed by Warwick FIRE for vent panel design for explosion mitigation, in the next version of European Standards EN 14994 [5.9]. The standard, which will apply across 34 countries, comes into effect in mid-2021. From then, all European companies designing venting panels for hydrogen installations have to follow the new version of the standard. This will lead to wider applications of the EM, which has already received several applications [5.3, 5.10a, 5.11a] after it was published in gold open access [3.2].

The Chinese Government’s Energy Strategy Programme in February 2020 adopted the EM in the safe design of a hydrogen station in Guangdong province. The Vice Chair of the Standards Committee for Hydrogen Energy said he was confident that “ the Warwick FIRE EM will be widely used in China to help ensure the inherently safer design of these refuelling stations and other hydrogen energy applications” [5.10a]. At the time of writing the supporting statement, another 50 hydrogen refuelling stations were planned for the remainder of 2020 [5.10a]; by June 2020, 11 had been built, with a further 200 now planned for construction in the next few years [5.10b].

The UK’s Department for Business, Energy and Industrial Strategy (BEIS), as part of the Government’s Clean Growth Strategy, established Hy4Heat in 2018. This programme aims to establish whether it is technically possible, safe and convenient to use zero-carbon hydrogen gas in residential and commercial buildings and gas appliances; such projects, if successful, could represent a seismic shift in decarbonisation for the whole of the UK – around 35% of UK’s CO₂ emissions come from the burning of natural gas, and the majority of this is from the heating of homes and cooking [5.11a].

Hy4Heat is project-managed by Arup, who, in conducting a thorough assessment of the safety measures required, used the EM developed by Warwick FIRE to predict the consequences of an internal vented explosion following the ignition of a confined hydrogen cloud within a domestic setting [5.11b]. The Senior Consultant of Resilience and Risk, Arup, confirmed that “ the Warwick FIRE group has been critical to the analysis work in the Hy4Heat Safety Assessment since 2019.”