Hydrogen, part of the UK’s future fuels story

Earlier this month the UK government announced its Energy Security Strategy, with a commitment for a £375m support package to spur the development of innovative energy technologies including nuclear, wind, solar and hydrogen as part of efforts to lower the UK’s carbon emissions and shore up energy security.

The new financial package includes £240m to support the production of ‘clean’ hydrogen. There are two approaches to producing hydrogen: blue hydrogen (produced by splitting natural gas into hydrogen and carbon dioxide) and green hydrogen (produced by splitting water via electrolysis into hydrogen and oxygen).

Green hydrogen requires a large energy input from a renewable source, but blue hydrogen cannot be described as a zero-emission fuel source.

The aim is to have up to 2GW of green hydrogen production capacity by 2025 and up to 10GW installed by 2030.

A further £2.5m of funding will go towards the development of next-generation nuclear technology and £5m towards research into carbon capture.

The IFE is already looking at what decarbonisation means for the fire engineering profession, bringing members and branches around the world together to identify best practice and the latest research to inform all aspects of fire engineering from design and innovation through to how first responders should deal with incidents, for example fires involving alternative fuel supplies or timber construction.

The technologies are advancing rapidly as nations around the world get to grips with reducing carbon impacts by transitioning to new fuels.

Hydrogen for Transport

In Sweden they have already introduced hydrogen powered refuse trucks¹; Mercedes Benz² has demonstrated how hydrogen can be used as an alternative to diesel to power HGVs and Japan and Australia are already collaborating on liquid hydrogen supply chain projects. In the UK, JCB has announced plans to fuel heavy plant and equipment that is poorly suited to battery power, by hydrogen.³ Mining giant Anglo American is also looking at powering its giant 220 tonne trucks with hydrogen.⁴

Indeed, hydrogen is primarily being trialled as an alternative to diesel for buses and heavyweight trucks and this includes fire trucks.⁵ This means changes to operational considerations when they become involved in fire.

Under the Transition to Zero Emission programme, Innovate UK⁶ is funding HySPERT (Hydrogen Special Purpose Electric vehicle platform for refuse collection and fire trucks), which sees Liverpool-based ULEMCo, a specialist in the conversion of commercial vehicles to hydrogen power, working in partnership with Oxfordshire County Council and its fire and rescue service to develop a design for a zero-emissions fire truck that can operate continuously for up to 40 hours.

The first stage will see partners develop an understanding of the specific duty cycles for emergency service vehicles that need 24/7 readiness, as well as enough energy on board for four to 40 hours continuous running, before a physical prototype is built.

Alongside the study, OCC will develop a plan for the hydrogen refuelling requirements across Oxfordshire FRS and explore how these fit with the wider plans to develop a hydrogen infrastructure across the county.

Hydrogen used in fuel cells has an energy to weight ratio ten times greater than lithium-ion batteries. Consequently, it offers much greater range while being lighter and occupying smaller volumes. It can also be recharged in a few minutes, much the same as refuelling gasoline vehicles. However, disadvantages include the availability of refuelling stations (in the UK, there are just 11); the cost of refuelling of between £10 and £15 per kg; and potentially less efficiency than batteries, from source of generation to fuelling the vehicle. Greater numbers of hydrogen refuelling stations will require changes to risk control methods.

Hydrogen in the Home

On the domestic front, hydrogen is also being lined up as part of the future energy mix for household boilers. Boiler manufacturers are working on a new ‘hydrogen-ready’ standard which will mean the UK can switch as easily as possible to 100 per cent hydrogen much further down the line. The important thing to realise is that ‘hydrogen-ready’ boilers are still in development, whereas ‘hydrogen-blend ready’ boilers are widely available.

The government is currently carrying out trials to work through all the cost, feasibility and safety issues – and they are expected to make firm decisions on what role hydrogen will play in heating the UK’s homes by 2026.

In the meantime, new boilers will be built to a new ‘hydrogen-ready’ standard, which means they will work with natural gas but can also be easily modified to run on 100 per cent hydrogen. According to some industry estimates, these boilers should be available from 2023-2025.

The plans to use a 20 per cent hydrogen blend will be introduced into the gas supply from around 2028 at the very earliest. The switch to 100 per cent hydrogen, probably will not happen until the mid-2040s.

Safety Aspects

In May last year, IOSH⁷ provided an overview of the risk of hydrogen fuel cells in vehicles that concluded that the two main hazards from fuel cell and hydrogen-powered vehicles are electrical shock and fuel flammability. Some fuel cell vehicle motors run on voltages exceeding 350V. With such high currents, the danger of electric shock is great, with 50V being high enough to stop the human heart.

Flammability is also an issue. Hydrogen has a flammability range between four per cent to 75 per cent in air, which is very wide compared with other fuels (gasoline is to 7.6 per cent). Under the optimal combustion condition (a 29 per cent hydrogen-to-air volume ratio), the energy required to initiate hydrogen combustion is much lower than that required for other common fuels (for example, a small spark will ignite it). However, hydrogen is about 57 times lighter than gasoline vapour and 14 times lighter than air. This means that if it is released in an open environment, it will typically rise and disperse rapidly. This is a safety advantage in an outside environment. Hydrogen also burns with an almost invisible flame, making it less noticeable and harder to firefight.

So, leakage can be a concern, especially when vehicles are stored in enclosed spaces as hydrogen can build up in roof spaces. Due to its small molecular size, hydrogen disperses quickly at normal atmospheric pressure. Therefore, it needs to be maintained at higher pressures (up to 10,000 pounds of force per square inch). The rupture of a pressure tank can cause high concentrations of hydrogen to form in the vicinity of the vehicle, as the turbulent flow rate of hydrogen is extremely high. Even though hydrogen disperses quickly, this emission will cause a combustible mix to form for a short period in the open.

All vehicles must be manufactured to minimum safety requirements, either nationally or internationally. The United Nations World Forum for Harmonization of Vehicle Regulations sets safety standards for motor vehicles. Standards for electrical safety, such as IEC 60664-1:2020 Insulation coordination for equipment within low-voltage supply systems – Part 1: Principles, requirements and tests, and ISO 19881:2018 Gaseous hydrogen – Land vehicle fuel containers, give minimum requirements for design specifications of components for electrical and fire safety.

H2Tools.org produced a paper based on the safety of hydrogen fuel cell cars.⁸ Researchers tested the electrical safety measures and leakage of hydrogen, both in use and post-crash. The electrical isolation and electrical continuity met the requirements in use and post-crash and no leakages from the tank were identified.

One of our largest special interest groups has a working group specifically looking at hydrogen vehicle infrastructure and transport. Legislation and regulations are piecemeal around the world and the aim is to bring learnings together to help shape a consistent approach that not only informs fire engineering professionals but can also help governments, regulators and legislators develop statutory guidance that can keep everyone safe in a fast-changing world.

For more information on how to get involved email: marketing@ife.org.uk