Energy
Where composites are largest and work hardest. Energy structures are huge, carry enormous loads, and must survive decades of fatigue in wind, waves and weather — so lightness, stiffness and corrosion-immunity beat almost everything else.
On the numbers: every material named links to its cited entry. This page is the map of where composites carry the load — from the biggest rotating structures on earth to the tank that makes hydrogen mobility possible.
Wind-turbine blades
The single biggest use of composites by mass — blades 60 to 115 m long that must survive ~10⁸ fatigue cycles across a 20-to-25-year life, bending in every gust.
e.g. Spar caps (stiffness), shear webs, aerodynamic skins
Pressure vessels & hydrogen
Filament-wound carbon stores gas at 350–700 bar at a fraction of a steel tank's mass. This is what makes hydrogen mobility possible — the tank is the enabling part.
e.g. Hydrogen & CNG tanks, rocket propellant, breathing air
Marine & tidal
Immune to the corrosion that rots steel — tidal-turbine blades, wave devices and offshore structure living in salt water, the harshest environment there is.
e.g. Tidal-turbine blades, wave-energy hulls, offshore parts
High-pressure tanks are classified Type I to V — a ladder that is really the story of replacing metal with composite to save mass. The blue band is the share of the load-bearing wall carried by composite:
A plain steel or aluminium cylinder. Cheap, heavy, and the reference point — industrial gas bottles.
A metal shell with a composite band wound around the cylinder to share the hoop load. Roughly a third lighter.
A thin metal liner is the gas barrier; a full carbon overwrap carries the load.
A plastic liner is the barrier only, fully carbon-overwrapped — the 700-bar standard for hydrogen cars.
Liner material →All-composite, no liner — the lightest of all, still solving gas permeation. Emerging.
Type IV — a plastic liner inside a filament-wound carbon shell — is the 700-bar standard behind fuel-cell cars.
Fatigue over decades
A blade flexes with every rotation — hundreds of millions of cycles over its life. The design driver is not a single peak load but fatigue: the slow accumulation of damage, which composites handle far better than metals if the layup is right. Size the layup with laminate theory.
The blade you can't recycle
A thermoset glass blade cannot be melted down — most retired blades are cut up and landfilled or burned in cement kilns. The mass that harvests clean energy at the top of the tower is the mass hardest to retire. Recyclable resins and thermoplastic blades are the fix in progress — and exactly the honest trade mpolyco exists to surface.
Part of the Make map. Browse the cited database, or see the other branches — aerospace, automotive, medical and 3D printing.