The overall purpose and ambition of HyAC is to address the two main obstacles for accurate and legal metering for commercial hydrogen fuel dispensing:- Validate and demonstrate that state-of-the-art hydrogen mass flow metering can meet expected legal requirements by conducting accuracy testing- Analyse existing legislation & standards on gas fuel metering accuracy and provide detailed recommendations on how hydrogen can be included and handledThe outcome of the HyAC project will primarily be a report named: ““Recommendations for legal requirements & procedures & for verification & approval of hydrogen metering accuracy”. Scope and purpose of the report will be to provide a thorough basis for later inclusion of hydrogen in the MID directive and OIML recommendation as well acting as a guideline for the handling of hydrogen by national authorities.In short term EU member countries may use HyAC results for individual handling legal accuracy processes for hydrogen. This may help enable an early roll-out of a hydrogen refueling infrastructure in key EU member countries where market introduction of fuel cell electric vehicles are considered, e.g. Germany, UK, Netherlands and Scandinavia.Also the HyAC project results can contribute to a potential inclusion of hydrogen in the European MID directive and OIML standard in medium to long term. This would provide a uniform approval process for hydrogen accuracy across Europe and help support a European wide roll-out of hydrogen refuelling infrastructure.To both collect input for the HyAC activities and secure a strong dissemination platform, networking and dialogue will be secured to authorities in selected EU member countries, working groups of MID and OIML, major European hydrogen initiatives (CEP, SHHP and UK/DE H2Mobilities) as well as major ongoing FCH-JU funded transport demonstration projects.