Work out tidal energy output instantly with clear inputs, formula shown and shareable results.
The potential energy in a tidal basin is 0.5 x seawater density x g x area x range squared, because the average head over the emptying cycle is half the range. Energy scales with the square of tidal range, which is why only a handful of sites worldwide with ranges above 5 metres are viable.
Tidal basin energy
E per cycle (J) = 0.5 x rho x g x A x R^2
Annual output
Annual energy = E per cycle x cycles per day x efficiency x 365
Tidal barrage and lagoon schemes have major effects on estuarine ecology, sediment transport and navigation, and require extensive environmental assessment and consent.
Single-basin ebb generation can only use part of the head, the turbines operate over a varying head far from their design point, and generation must stop while the basin refills. Two-way and multi-basin schemes improve on this at higher cost.
Yes, decades ahead, which is its main advantage over wind and solar. It is not, however, dispatchable — output follows the tide, which shifts about 50 minutes each day relative to demand.