This production rate of hydrogen of about 96 kg/h is quite significant, which depending upon the application might require a significant amount of storage. There will be a need to determine how many kg the project wants to store from this production rate in order to determine how much hydrogen ground storage is needed. Since the project is in Europe, look for pressure vessel manufacturers that offer PED approval for their vessels. 

There are many types of vessel construction other than Type 4 vessels for ground storage.  General vessel types also include Type 1 which are more traditional metallic vessels, Type 2 which are hoop wrapped, Type 3 which are fully wrapped with metallic liners, and Type 4 which are fully wrapped with non-metallic liners.
Selection between these types of vessels is highly dependent upon the design attributes (e.g., weight, service conditions, longevity, etc.), the nature of the process (pressure, temperature, cycles, etc.), and economics. The Panel is not in a position to endorse a particular type, brand or vendor. There are many vendors that can supply a variety of these types of vessels. It is important to develop a process specification for a vendor to quote since the application will have a significant effect on the economics of one type compared to another.

It is important to be aware of the local pressure vessel Codes within your jurisdiction. Virtually any manufacturer can help with that determination if requested but it’s also prudent to confirm with the local authority having jurisdiction. The manufacturer can also assist with the User Defined Specification for your service as well recommend   the storage pressure and number of vessels that might be optimized to store the quantity of hydrogen needed. Storage vessel cost may range from $500 up to $2000 per kg stored depending on the requirements selected. There are also many indirect costs related to storage such as relief devices, piping, freight, foundations, and installation that also must be considered as part of the overall assessment.
 

The British Standards Institute (BSI) has published BS ISO 22734:2019, a British nationalized version of the packaged water electrolyzer safety certification standard. This standard can be used by a Notified Body (BSI is one of many operating in the UK and in Europe) to certify electrolyzer safety to established norms for this equipment. This standard addresses safety of containerized hydrogen generators using low temperature water electrolysis technologies PEM and KOH. It includes requirements to assess hazardous area classification using IEC 60079-10 and to employ methods to mitigate hazardous areas using air dilution and/or equipment designed for hazardous areas per the ISO 60079 series in accordance with the ATEX directive. The standard provides requirements for on-board GH2 storage.