The basic concept of H2REF projects

These two projects H2REF and H2REF-DEMO are based on a same innovative compression technology using blader accumulators.

Bladder accumulator-based compression is applicable to any refuelling applications, thanks to the combined high scalability of hydraulics technology and carbon composite pressure vessels. Indeed, high pressure hydraulic pumps are already available and successfully delivering very large capacities for many oil and gas applications. Similarly, high pressure accumulators in carbon composite material are also currently available and can be built to very large sizes.

A fundamental advantage of bladder accumulator-based compression for compression and transfer of hydrogen over conventional mechanical compression, is that it uses serially produced components from a mature and standardized industry (hydraulics and composite pressure vessels) with a world-wide supplier base, minimising cost while providing excellent robustness and reliability.

Furthermore, bladder accumulator-based compression provides the following additional benefits:

  • high scalability, thanks to the combined high scalability of hydraulics and carbon composite pressure vessels,
  • high flexibility, thanks to the wide operating pressure ranges of the components;
  • high flow-rate and small foot-print: as compression effort is applied by means of a working fluid driven by a hydraulic pump;
  • maximized compression capacity, thanks to uniquely taking advantage of varying pressure upstream, while operating at constant power (even though the discharge pressure to suction pressure ratio changes),
  • reduced energy consumption, thanks to the exploitation of upstream pressure.
    • the average energy consumption is halved as the pressure of the stored hydrogen is fully taken advantage of;
    • the on-going adoption of higher storage pressure in the hydrogen supply chain further increases the benefit of taking fully advantage of the source storage pressure;
  • improved reliability and reduced maintenance requirements, intrinsic to hydraulic power technology,
  • exploitation of the full compression power capacity at all times, maximizing effective throughput.


H2 refuelling station for passenger vehicles


H2 refuelling station for heavy vehicles