A rotor can never take more than 16/27 ≈ 59.3% of the wind's kinetic power — the Betz limit — and real machines fall further short of even that. Set the wind speed, rotor diameter, air density, power coefficient Cp and drivetrain efficiency η and watch the electrical output climb along a power curve gated by cut-in, rated and cut-out wind speeds, with a loss bar showing exactly where the rest of the kinetic power goes. Feed that intermittent output into a battery — capacity, load and round-trip efficiency — and watch the state of charge ride out calm spells over a day. It all runs on your device.
You are in the Physics lab.
Wind in, electricity out — and the losses along the way.
Smoothing an intermittent supply against a steady load.
What the gauge, the curve and the loss bar are telling you — then what the battery does with the result.
The turbine spins faster as wind speed climbs, and the gauge beside it fills toward the rated power — the ceiling the machine is built for. Push the wind speed past the cut-out slider and the rotor stops: real turbines feather their blades and shut down in a storm rather than risk damage, so the gauge drops back to zero exactly where it should.
The power curve plots output against wind speed: flat at zero below cut-in, climbing as the cube of wind speed to rated, flat at the rated power up to cut-out, then zero again. The loss bar breaks that same instant down into four slices of the wind's kinetic power: the share no rotor can ever reach (Betz), the further shortfall between your Cp and the Betz ceiling, what the drivetrain eats via η, and what's left as net electrical capture — the smallest slice, and the only one you actually get.
The Storage card feeds a simulated day of wind — built from your mean wind speed — through the same turbine into a battery serving a constant load. The state-of-charge trace climbs when generation beats the load and falls when it doesn't; if it would fall below zero that stretch counts against unmet-load time. Autonomy is simply capacity divided by load, and capacity factor compares the energy actually delivered over the day to what the turbine would deliver running at rated power the whole time.
A hard ceiling on extraction, a curve shaped by cut-in and cut-out, and a battery to bridge what the wind won't hold still for.
The kinetic power in wind moving through a rotor's swept area is P = ½ρAv³ — it scales with air density, swept area, and the cube of wind speed. No rotor can extract all of it: slowing the wind completely would block the air stream, so the physical maximum, proven by Betz, is 16/27 ≈ 59.3%. That ceiling is set by the airflow itself, not by blade design.
Below cut-in there isn't enough wind to turn the rotor usefully, so output is zero. From cut-in to rated wind speed, electrical output is η·Cp·P, rising with the cube of wind speed. Above rated, the turbine deliberately sheds power — pitching its blades — to hold output flat and protect the gearbox and generator, until cut-out, where it shuts down entirely rather than risk damage in a storm.
Because generation follows wind, not demand, a battery is what actually lets a constant load be served: it charges on the surplus and discharges through the gaps, at a round-trip efficiency below 100%. Its capacity sets how many hours of autonomy it buys against the load, and over a full day the capacity factor — actual energy over rated-power energy — tells you what fraction of the turbine's nameplate rating the wind really delivered.
Moving air pushes the blades — shaped like aircraft wings — turning a hub at 10–25 rpm; a gearbox steps that up to the generator, which makes electricity; a transformer raises the voltage for the grid, and a battery can bank the surplus for calm spells. Below cut-in the rotor won't start; past cut-out the blades feather to a stop for safety.
Learn more: our data study on capacity factor vs the Betz limit · Wind turbine (Wikipedia)