Increasing fuel costs and the ongoing need to reduce carbon emissions means that businesses continue to look at reducing their reliance on the fossil fuel internal combustion engine. Electric vehicles are at present the main contender, although hydrogen-based technology could provide another alternative for commercial vehicles. Hydrogen has been used for many decades in various industries and provides a high energy density fuel when burned, producing no greenhouse gases. However, hydrogen also presents several hazards and there are safety factors to consider when planning its storage and use.
Understanding hydrogen vehicles
Hydrogen is the most abundant element on the planet and can be produced in several ways such as electrolysis of water, natural gas reforming, biomass derived liquid reforming, and microbial biomass conversion. At present, the majority of hydrogen is produced by burning fossil fuels, but as renewable electricity generation becomes more prevalent, the production of hydrogen can become ‘greener’.
Most hydrogen-fuelled vehicles use fuel cell technology with a propulsion system similar to electric vehicles. The hydrogen energy is converted into electricity by a fuel cell with a battery provided to enable regenerative braking, provide power during acceleration, and to smooth out power delivery from the fuel cells.
The hydrogen itself is stored in a high-pressure tank and can be refilled within a few minutes from a hydrogen refuelling station (HRS). The HRS includes one or more high-pressure hydrogen storage tanks, a gas compressor, a pre-cooling system, and a high-pressure hydrogen dispenser.
Convenient refuelling presents one of the main challenges when considering this innovative technology, with only a few HRS available across the UK. One article published in June 2023 (opens a new window) estimated the cost to build an HRS at around £2 million.
The use of hydrogen also requires several important engineering controls to ensure its safe storage and use. Hydrogen has a very wide explosive limit (4%–75%) when compared to other fuels, burns with a near invisible flame, leaks more easily, has a lower ignition energy, is easier to detonate, and can cause hydrogen embrittlement to some metals, among other characteristics.
Loss example:
An explosion and fire occurred at a hydrogen refuelling station in Norway (2019). The cause was reported to be an assembly error of a specific plug in a hydrogen tank, causing a leak. In addition to the associated property damage, two people required medical attention.
Property risk
The introduction of a HRS introduces new property fire and explosion risks to a business enterprise. Where provision of new HRS infrastructure is being considered, the property fire risks should be carefully identified, assessed, and managed in consultation with an insurance broker, insurer, and other stakeholders such as regulatory bodies to develop appropriate property protection strategies.
Key considerations include:
Risk assessment – ensure compliance with fire, explosion, and process safety legislation including fire risk assessments and process safety hazard analysis. Hydrogen is a named dangerous substance in the UK’s Control of Major Accident Hazard Regulations 2015 (COMAH) (referred to as the Seveso III Directive across Europe) with a lower-tier threshold of five tonnes and upper-tier threshold of fifty tonnes, requiring additional controls over these quantities.
Location – consider suitable separation distances to avoid impacts to other buildings or critical infrastructure in the event of fire or explosion. Encourage natural ventilation to disperse potential leaks or provide mechanical ventilation where this is not possible.
Design & installation – utilise competent persons in the design and installation of the facility, using appropriate codes and standards. Materials need to be compatible with hydrogen to avoid the risk of hydrogen embrittlement or other causes of loss of containment. Ensure appropriate electrical equipment is selected for use within hazardous zones (potential explosive atmospheres). Prevent build-up of static electricity with electrical earthing and bonding.
Safety systems – install equipment which limits the escape of hydrogen following equipment failure, such as in the event of vehicle driveaway. Provide suitable alarms, interlocks, shut-down systems, and pressure relief systems, as determined by the process hazard analysis and regulatory requirements. Consider the installation of hydrogen flame detection – when hydrogen burns it emits very little light, so is not readily identified by the human eye.
Management controls – implement safe systems of work for the operation, maintenance, and inspection of the facility utilising competent persons in line with manufacturers guidelines.
Emergency response – prepare an emergency response plan providing information for both site personnel and emergency responders. Where appropriate, consider the provision of automatic fire suppression and manual fire water supplies.
For further information, please visit the Lockton Risk Control (opens a new window) page, or contact:
Mark Middleton, Risk Management Executive
T: +44 207 933 1632
