This simulation drives a sinusoidal tidal current over the real 12.4-hour semidiurnal cycle and lets you extract power from it two ways: a submerged stream turbine spinning in the current (P = ½ρAv³, capped by the Betz limit), or a barrage generating from the head of water built up across a dam (P = ρgQH). Watch the power curve trace out twin peaks each cycle as the tide floods and ebbs, and see how spring versus neap phase, rotor size and cut-in speed change how much energy you actually harvest.
A cross-section of a tidal channel with flow particles drifting with the current, either a spinning three-blade stream turbine or a barrage dam wall with water levels on each side, plus a live power-versus-time plot spanning the full 12.4-hour tidal cycle with a marker for the current instant.
Switch mode between Tidal stream and Barrage, adjust tidal range, spring-neap phase, rotor diameter/barrage size, power coefficient Cp, cut-in speed and time speed, or jump to a preset (Strong stream, Neap, Large barrage, Spring peak) to see power, peak power, energy per cycle and capacity factor update.
Unlike wind or solar, tidal power is almost perfectly predictable years in advance — the current reverses on a fixed 12.4-hour schedule set by the Moon's orbit, which is why the power curve here traces the same twin-peaked shape every cycle rather than fluctuating randomly.
The tide floods in one direction then ebbs back in the other over a 12.4-hour semidiurnal cycle, and current speed peaks partway through each half — since power depends on v³ regardless of direction, both flood and ebb produce a power peak.
Spring tides occur when the Sun and Moon's gravitational pulls align, producing the largest tidal range and strongest currents; neap tides occur when they're at right angles, producing a much smaller range. The "spring-neap phase" slider scales the tidal amplitude between these extremes.
It's the same 0.593 theoretical ceiling that applies to wind turbines, since a tidal stream turbine extracts kinetic energy from moving water the same way a wind turbine extracts it from moving air — the power coefficient Cp slider is capped at that value.
A barrage dams an estuary and lets water build up a height difference (head) between the sea and basin sides, then releases it through turbines — power depends on that head and the volume flow rate, following P = ρgQH, rather than directly on current velocity cubed.
Below the cut-in speed, the current is too weak to usefully turn the turbine, so power output is zero — raising this slider means the turbine needs a stronger tidal current before it starts generating at all.