Hydrogen and its competitors, 2004

Risø Energy Report 3Hydrogen safety 656.2deal with domestic fuel cells with capacities of up to 70kW. This initiative follows demonstration projectsinvolving small fuel cell systems, where neither appropriateregulations nor standards exist.RegulationsEuropean directives (the Machinery Directive, ElectromagneticCompatibility Directive, Gas Appliance Directiveand others) apply to hydrogen systems whose manufacturersseek CE labelling. All these directives basicallycome down to risk assessment and safety features, andthey apply to all self-contained products and systems,including portable and stationary fuel cells andhydrogen generators. CE labelling is compulsory for anyproduct that is intended to be sold, rented or lent on theEuropean market.Large hydrogen plants such as steam methane reformersrely on the Major Hazards Directives and related nationalregulations.Other European directives apply to cars. Existing directivesdo not cover neither gaseous nor cryogenic storageof hydrogen in cars. As with compressed natural gas(CNG) and LPG vehicles in the past, discussions are nowtaking place in Geneva under control of the dedicatedworking group UNECE WP29 (United Nations EconomicCommission for Europe, Working Party 29). Currentwork is based on two draft documents for on-boardhydrogen storage (gaseous and liquid), submitted by theEuropean-funded European Integrated Hydrogen Project.(EIHP)Prospects for the safe use of hydrogen as anenergy carrierRecent and future work on regulations and standardsfocuses on the safe use of hydrogen by untrained people.These regulations and standards are based on:• experience learned from past incidents and accidents;• a scientific approach; and• public expectations.So far, experience with new hydrogen technologies isscarce and is usually subject to commercial secrecy. Standardsthat are drawn up too early might miss crucialsafety points. A substantial input from scientificresearchers is therefore required. This scientific processshould focus on:• the long-term effect of hydrogen on materials used forpiping, vessels and fittings under extreme conditionsof pressure or temperature;• requirements for equipment in potentially explosivehydrogen atmospheres;• requirements for ventilation in car parks, garages,tunnels and other enclosed areas;• the consequences of the diffusion of stored hydrogen,and ways to mitigate this;• the consequences of accidental releases from storageand distribution systems, and ways to mitigate these;• safety aspects of the behaviour of untrained consumersand their interaction with hydrogen technology, suchas refuelling and vehicle maintenance.The EIHP working group on safety concludes that overallhydrogen is no more hazardous, than conventional fuels[4]. However, says this group, the many ways in whichhydrogen differs from conventional fuels make it necessaryto perform detailed risk assessments for every stagein the hydrogen supply chain. A general requirementwill be that hydrogen-based applications are always saferthan the corresponding applications using conventionalenergy carriers.Standards are based on consensus among companieswho may be more interested in the technological andeconomic aspects than the science of safety. There musttherefore be a dialog between standardisation workinggroups and safety experts, so that any doubts by thelatter can be expressed and dealt with.Safety was an integral activity of the EIHP [5], and thiswork will continue in a newly-created network of excellenceentitled HYSAFE (Safe Use of Hydrogen as anEnergy Carrier). HYSAFE brings together hydrogen safetyexperts from companies and research institutes acrossEurope, creating a meeting point for experts, standardsworking groups and national authorities. To promote itsscientific and risk-based approach, HYSAFE plans tocreate a wide range of experimental and numerical toolswhich it can then use to investigate the safety ofproposed standards.The European Hydrogen and Fuel Cell platform and itsdedicated working group on regulations and standardskeeps an overview of the development of standards andidentifies the need for new initiatives in this area.Conclusions and recommendationsThe international discussions now taking place will helpto ensure adequate safety in the new hydrogen technologies.Early attention to safety issues, yet with carenot to rush into premature technological pronouncements,and striving for international consensus all reinforcethe idea that safety should be an integral part ofhydrogen technology, and will help rather than hinderthe growth of the hydrogen economy.If these recommendations are followed there is no reasonto believe that hydrogen will be riskier than conventionalfuels. Accidents will happen, but careful planningwill provide an acceptable level of safety and ensure thataccidents such as the one in Stockholm remain rare.