For years, Composite Pressure Vessels (CPVs) have offered lightweight storage of hydrogen (H2) for zero-emission fuel cell-powered vehicles via Type-IV tanks comprising plastic liners wrapped with carbon fibre and epoxy resin. Though H2 has long promised a sustainable source of clean energy, progress has been slow until recently. With the lighter Type-V CPVs yet to demonstrate the ability to remain impermeable at demanding operating conditions and the need of various sectors (e.g., aerospace) for lightweight solutions, HYBAR aspires to develop and commercialise an impermeable all-composite Type-V tank (CPV) for H2 storage in aviation. The ΗΥBAR tank (CPV) will be manufactured by combining An advanced Type-V CPV manufacturing process was developed in-house (patented) for years by the project coordinator, combining dry filament winding with nanomaterial inclusion (graphene nanoplatelets). Multi-layered graphene has been demonstrated to decrease hydrogen permeability by up to 48 times and, consequently, forming a protective barrier and making the CPV impermeable; An epoxy-based layer enhanced with ceramic nanoparticles as an internal high-barrier layer (between the composite wall and the stored hydrogen) aiming to provide zero (or close to zero) permeation and resilience to demanding operating conditions; An innovative fibre architecture called Helicoid (patented) that involves stacking layers of parallel fibres each rotated slightly (10 – 15 degrees) to form a helicoidal structure, enabling enhanced toughness, strength, and damage tolerance; AI-driven in-process monitoring module capable of detecting defects during manufacturing; An LCA-driven framework that will drive the development of the tank, leading to a final solution with a low environmental impact. In a nutshell, HYBAR will be a game-changing, innovative, and disruptive H2 storage solution, enabling a new generation of mechanically robust impermeable CPVs with (i) enhanced structural integrity, (ii) close-to-zero permeation, (iii) 25% lighter compared to conventional Type-IV tanks in the market and 5-10% lighter than other SoA Type V composite tanks, targeting a gravimetric efficiency for hydrogen storage of 70%. Targeting the aerospace market, the all-composite tank will be manufactured through a single processing route, offering higher product quality, improved manufacturability, improved energy efficiency, reduced production costs, and shorter lead times. The participation of an aerospace industrial partner, Turkish Aerospace Industries, who is keen to exploit the final H2 storage solution after a successful project outcome (reaching TRL6), will ensure that the HYBAR tank development is driven by customer/end-user needs in compliance with aerospace regulations.