Lesson 3 of 7

Wind Power

7 min read

Wind power does have a spinning generator, unlike solar — but modern wind turbines connect to the grid in a way that's much closer to solar's power-electronics approach than to a traditional synchronous power plant, for reasons this lesson explains.

From moving air to electricity

Wind turns the turbine's blades, which spin a shaft connected — usually through a gearbox, though some designs skip it — to a generator. The amount of energy available in wind scales with the cube of wind speed, which is why turbine siting and blade design are so sensitive to even small differences in average wind speed at a location.

The power curve: three key speeds

Cut-in speed: The minimum wind speed at which the turbine starts generating any usable power — below it, the turbine simply stays idle.
Rated speed: The wind speed at which the turbine reaches its full rated (nameplate) power output.
Cut-out speed: The wind speed above which the turbine deliberately shuts down and feathers its blades to avoid mechanical damage — meaning, somewhat counterintuitively, that a wind farm can produce zero power during a very high-wind storm.

Between cut-in and rated speed, output rises steeply (following that cube relationship); between rated and cut-out speed, control systems deliberately limit output to the rated value rather than let it keep climbing — this combination is what defines a turbine's overall power curve.

Fixed-speed vs. variable-speed turbines

Early wind turbines used generators connected directly to the grid, forcing the turbine to spin at a fixed speed tied to grid frequency — simple, but unable to capture wind energy efficiently across the full range of wind speeds. Nearly all modern turbines instead use variable-speed designs, most commonly a Doubly-Fed Induction Generator (DFIG) or a full-power-converter generator, both of which let the turbine's rotor spin at whatever speed best captures energy from the current wind, while power electronics handle converting that variable-frequency output into grid-synchronized AC.

Why this connects to the next lesson

Because variable-speed turbines are decoupled from grid frequency by power electronics, a modern wind turbine — much like solar PV — fundamentally relies on inverter/converter technology to actually deliver power to the grid, not a direct mechanical connection. That makes inverters the shared foundation underneath almost every modern renewable technology, which is exactly why the next lesson is dedicated to them.

Onshore vs. offshore wind

Offshore wind benefits from stronger, steadier wind and fewer siting/visual-impact objections, generally giving it a higher capacity factor than onshore wind — but construction, foundations (or floating platforms in deep water) and subsea cabling make it substantially more expensive to build and maintain than an equivalent onshore project.

Key takeaways

Available wind energy scales with the cube of wind speed, making siting and blade design highly sensitive to local conditions.
A turbine's power curve is defined by cut-in, rated and cut-out wind speeds.
Modern variable-speed turbines (DFIG or full-converter) use power electronics, not a fixed mechanical link, to synchronize with the grid.
Offshore wind generally has a higher capacity factor than onshore, at significantly higher construction and maintenance cost.