A plain-English guide to the wind turbine blade: how long it is, how much it weighs, what it is made of, and the service that keeps it running.
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The wind turbine blade is the single component that turns moving air into rotation, and the most exposed part of the whole machine. This guide explains blade length, weight, materials, types and lifespan, covers the common blade damage owners deal with, and links each one to the repair and protection service that addresses it.
Blade length is the headline number for any modern turbine, because it sets the rotor diameter and therefore the area the rotor sweeps. Utility-scale wind turbine blades commonly run from about 50 metres on older onshore machines to 80 or 90 metres on the largest onshore and offshore platforms. A 75-metre blade produces a rotor roughly 150 metres across. Longer blades sweep more air at a given wind speed, which is why length has grown with every turbine generation. That same growth is what makes blade transport, crane lifts and blade repair access harder and more specialised each year.
A single utility-scale blade typically weighs between 10 and 25 tonnes. A 50-metre blade sits near the lower end, while 80 to 90-metre blades on the biggest machines reach the top of that range. Weight matters for two reasons: it drives the loads carried by the hub, pitch bearings and main shaft, and it dictates the size of crane needed for any blade exchange. Manufacturers fight weight growth with carbon-fibre spar caps and optimised shell layups, because a blade that gets heavier faster than it gets longer puts more strain on every component behind it.
Blades are composite structures built mainly from fibreglass (glass-fibre reinforced polymer, or GFRP) laminates. The glass fibres are laid up and bonded with an epoxy or polyester resin that sets into a stiff, strong shell. In longer blades, carbon fibre (CFRP) is used in the spar caps, the load-bearing strips that run the length of the blade, because it adds stiffness without adding much weight. The shells are usually a sandwich panel with a lightweight balsa wood or foam core between two laminate skins, which keeps the large panels rigid without filling them with solid laminate. A gelcoat or protective coating finishes the outer surface and takes the first hit from rain and grit.
Almost all large turbines use three-bladed, upwind, horizontal-axis rotors, a layout that balances efficiency, loads and cost better than one or two-bladed designs. Within that, blades differ by construction: most are built in two shells bonded along the leading and trailing edges around internal shear webs, while some use a one-shot or integrated-spar approach. Blades also differ by whether the spar caps are glass or carbon, and by tip design, with serrated trailing edges and winglets used to cut noise and boost aerodynamic performance. All of these still rely on the same maintenance paths, from inspection to lightning protection.
Blades are designed for a service life of 20 to 25 years, the same design life as the turbine. Whether a blade reaches that span depends on how well it is maintained: leading-edge erosion, lightning strikes, delamination and fatigue cracking can all shorten it if they go unaddressed. Regular inspection and timely repair are what keep a blade on track for its full life, and many are extended beyond it under formal life-extension assessments. For context on the wave of Australian turbines now ageing out of warranty, see our blog on leading-edge erosion. At true end of life, blades move into decommissioning and repowering, where recycling of composite material is the growing focus.
The most common blade problem is leading-edge erosion: years of rain, dust and insect impact slowly roughen and strip the leading edge, which quietly shaves off annual energy production before it becomes a structural concern. The fix and the prevention both sit under leading-edge protection. Delamination, where the laminate layers separate, and surface or structural cracks from fatigue are the next most common, often starting small and spreading if left alone. Lightning strikes at the tip can blow out laminate and damage the down-conductor system, which is why a sound lightning protection path matters. Bond-line failures along the trailing edge round out the list. Caught early through inspection, nearly all of these are repairable under blade repair rather than requiring a full blade exchange.
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