Learnings

Outcomes

The outcomes of the project came in the form of various reports, all of which have now successfully completed their review by HSE. Comprehensive details of the outcomes of the project are contained within these reports and will be made publicly available in due course, once a communications plan for the full suite of hydrogen safety evidence delivered since Hy4Heat has been agreed by all the relevant stakeholders.                                                                                                                                                                                  

The key findings of the project are summarised below:

·       Hydrogen is more detectable than methane.

·       Hydrogen dispersion is more uniform than methane.

·       Hydrogen leakage is likely to be detectors more quickly than methane for equivalent leakage scenarios.

AIV systems that use gas detectors have therefore been shown to be a good hazard mitigation method to respond to leakage in gas installations using hydrogen.

The three commercial AIV systems that were purchased and tested were all found to be suitable for their intended purpose. They all detected hydrogen more quickly than methane from equivalent leaks, and they also detected and shut off smaller leaks with hydrogen than with methane. This demonstrated the improved detection with hydrogen.

Due to hydrogen dispersing more uniformly than methane, detector placement was found to be less critical for AIV systems with hydrogen than it is with methane. For small leaks, AIVs will detect and isolate the gas supply before flammable concentrations can build up anywhere in the protected space. However, for large leaks, there is a possibility that flammable gas plumes could build up in some parts of the protected space before the gas reaches the detectors. The placement and number of detectors has the greatest impact on the rapid detection of large leaks.

Lessons Learnt

The key lesson learnt was the importance of being flexible with the project plans in first-of-a-kind research such as this. Given that the project was a research project, expectations at the start were somewhat limited, however, it was early engagement with a range of stakeholders that really helped to shape what successful project delivery would look like. The early findings of the literature review and commercial property surveys in Whitby and Redcar allowed the project plan to adapt to be able to produce more valuable outputs, rather than stay rooted in its original scope and deliver an unsatisfactory result. As part of this flexibility, there must also be the appropriate governance and change control processes in place so that changes to the project scope can be presented and approved by the relevant stakeholders outside the immediate project team. The project used the governance structure available in the wider Hydrogen Heating Programme (HHP) led by the Department for Energy Security and Net Zero (DESNZ) to ensure the scope modifications were socialised and approved before any delivery of the proposed new scope was undertaken.

Building on this, it’s worth calling out the often-understated importance of stakeholder engagement in the delivery of technical research projects. The project engaged early with HSE, AIV component manufacturers/suppliers, property survey teams within the Whitby and Redcar Hydrogen Village Trial areas to ensure that the project could go on to deliver outputs that were as useful as possible to as many as possible.

The learnings from the project can be exploited further in early hydrogen heating demonstrations, as theory and experimental work can only take you so far. That being said, AIV systems are already well understood and widely used in industrial and commercial premises under natural gas service. The key lesson learnt from this project is around the use of gas detectors to enable better interlocking methods with the solenoid valves, so that gas supply is not being isolated unnecessarily in the event of unrelated emergencies.