The three-year HyTunnel CS project culminated in the report titled Deliverable D6.9, “Recommendations for inherently safer use of hydrogen vehicles in underground traffic systems.” The HyTunnel CS project aimed to perform pre-normative research for the safety of hydrogen-fueled vehicles traveling through tunnels or entering confined spaces. The main objective was to compare the relative risk of hydrogen vehicles entering underground traffic systems to existing fossil fuel-powered vehicles [1].

The information in this document provides answers to the questions that were raised during the Center for Hydrogen Safety September 4, 2023 webinar.

Safe practices in the production, storage, distribution, and use of hydrogen are essential for the widespread acceptance of hydrogen and fuel cell technologies. A catastrophic failure in any hydrogen project could damage public perception of hydrogen and fuel cells. Given the nascent nature of the mobile hydrogen applications, incidents involving mobile equipment can have detrimental impacts for the public as well as stakeholders and project proponents who are committed to hydrogen’s use as a safe alternative energy resource. 

Natural gas distribution companies are developing ambitious plans to decarbonize the services that they provide in an affordable manner and are accelerating plans for the strategic integration of renewable natural gas and the blending of green hydrogen produced by electrolysis, powered with renewable electricity being developed from large new commitments by states such as New York and Massachusetts. The demonstration and deployment of hydrogen blending have been proposed broadly at 20% of hydrogen by volume.

State policy targets on greenhouse gas emission reductions and other decarbonization initiatives are creating a movement toward low or zero-carbon gases and fuels. Given its versatility as an energy carrier and its potential for use in a broad range of applications, hydrogen is gaining in popularity, and natural gas providers are looking at integrating it into their networks.

Several codes require excess flow valves in pipelines so that in the case of line rupture, the flow will be shut off.   In theory, this is a good idea, however, in practicality, it has many limitations.  The sizing and practical uses make the sizing difficult if sometimes impossible, depending on the design parameters.   

Hydrogen is a key energy carrier for modern society. The breaking of the hydrogen bonds within traditional hydrocarbon molecules has been the primary mode of energy utilization since the industrial revolution. An increased focus on “net-zero” greenhouse gas emissions, specifically carbon dioxide and methane, has resulted in a global push for lower carbon energy vectors, including pure hydrogen.

This document applies to the recovery phase of a typical emergency management framework that includes planning, response, mitigation, and recovery. This document provides practical guidance with a checklist to help an organization recover from a hydrogen incident and return to normal operations after the event scene has been stabilized and returned to the organization by the incident commander. This document does not include activities related to the immediate emergency response and initial investigations performed by other entities.

An under-expanded hydrogen jet from high-pressure equipment or storage tank is a potential incident scenario. Experiments demonstrated that the delayed ignition of a highly turbulent under-expanded hydrogen jet generates a blast wave able to harm people and damage property. There is a need for engineering tools to predict the pressure effects during such incidents to define hazard distances. The similitude analysis is applied to build a correlation using available experimental data.

Contents 1 Climate Change Policy Objective 2 Hydrogen Flexibility 3 Hydrogen Production and Sources4 Hydrogen Properties5 Hydrogen Safety Codes and Standards Overview6 UK Hydrogen Blending Demo Approval7 US Hydrogen Blending Concept8 Pipeline Integrity9 Gas Composition Standards10 Pipeline Standards11 Hydrogen Safety Utilization 12 Conclusion