Tidal Energy Simulator

The HydreManche simulator shows how current speed influences both the mechanical loads acting on a structure and the power that can be recovered by a tidal turbine. It helps visualise the essential orders of magnitude: output that depends strongly on current speed, loads that also increase, and the gap between installed capacity and real-world production.

Tidal energy: installed capacity or actual production?

Installing 1 MW does not mean producing 1 MW continuously.
Energy policy targets are often expressed in installed capacity (MW), including in France’s Multiannual Energy Programme (PPE).
Actual generation is measured in megawatt-hours produced over time (MWh).

In tidal energy, this gap can be substantial.

Why tidal power output varies so much

The instantaneous power of a tidal turbine is given by:

P = ½ × ρ × A × V³ × C_p
with A = π × D² / 4

It depends on the following factors:

– the density (ρ) of seawater, approximately 1025 kg/m³,

– the rotor swept area (A), which depends on the square of the diameter (D²),

– the machine’s power coefficient (C_p) (e.g. 0.25),
– and above all, the cube of the current speed (V³).

As a result, when the geometry and characteristics of the machine remain broadly unchanged in the short term, current speed becomes the key factor determining instantaneous power. Even a modest change in speed can produce a very large change in power. At sea, current speed varies cyclically under the effect of the tides, driven by lunar and solar cycles.
Instantaneous power therefore varies sharply over time, because it depends on the cube of the current speed (V³).
Annual production is the result of integrating these successive variations over time.

What this simulator shows

Production depends on the cube of the current speed (V³).
Structural loads depend on the square of the current speed (V²).
The rated current speed (V_nom) determines the declared installed capacity in MW.
A rated power (P_nom) declared without its associated rated current speed (V_nom) has no usable physical meaning.
Pour comprendre ce que ce modèle simplifie et ce qu’un site réel ajoute comme contraintes, voir la page 👉Compléments techniques.

How to use the simulator

Set the parameters on the left, select the observation period, then compare current speed, structural loads and power output.

Hydrolien — Simulateur V²/V³ (v07a CLEAN)

Simulateur hydrolien — vitesse, effort et puissance

Lang

Comparer la vitesse du courant, les efforts sur la structure et la puissance récupérable.

Vitesse maximale du site à 100 % (m/s)

Vsite(100%) = 4.20 m/s

Amplitude marée (coef 20 à 120)

Amplitude = 70% · coef 84

Échelle de temps

Puissance nominale Pnom (MW)

Pnom = 1.0 MW

Vitesse nominale Vnom (m/s)

Vnom = 3.50 m/s

Coefficient de performance Cp

Cp = 0.40

Rendement hydrodynamique du rotor.

Diamètre du rotor D (m)

Calculer D pour atteindre Pnom à Vnom

D = 19.5 m → Surface A ≈ 299 m²

D recalculé automatiquement selon Pnom, Vnom et Cp.

Coefficient de poussée (Ct)

Coefficient de poussée Ct = 1.20

Effort de poussée du rotor.

Inclure structure (approx.)

Effet de structure (× rotor)

Effet de structure ≈ 1.0 × celui du rotor

Paramètre simplifié à affiner selon la conception. La mutualisation de plusieurs machines sur un même support peut réduire ce facteur par machine.

Effort max (scénario) :
Moment max (scénario) : (bras z ≈ 0.7×D)

Prix (€/MWh)

Prix = 100 €/MWh

Puissance moyenne (fenêtre)

Facteur d’utilisation (fenêtre)

— %

Estimation fondée sur la puissance moyenne de la fenêtre affichée.

Lecture instantanée (curseur vertical)

Vitesse instantanée

m/s (±), km/h, nd

Puissance injectée

pics “flash”

Voir le calcul

Effort structural ~ V²

tonnes (≈ t)

CA instantané

€/h (P×prix)

Axe vertical de lecture

Position = 50% • V=— m/s • P=— MW • F=— kN

When power output becomes a structural issue

The simulator highlights a fundamental trade-off: improving the regularity of power output often increases the mechanical loads borne by the structures. It shows how variations in current speed affect both structural loads and recoverable power.

In very high-current areas, the issue is therefore no longer purely about energy — it becomes structural:
how can large-diameter machines be deployed durably under extreme hydrodynamic conditions?

The HydreManche® foundation concept addresses this issue directly.

👉 Découvrir l’approche structurelle

Limitations of the simulator

This simulator is intended as an educational tool. It is not a substitute for a detailed hydrodynamic study, industrial engineering design, or real-world testing.

The displayed results provide orders of magnitude for understanding how current speed relates to structural loads, recoverable power and estimated production. The underlying assumptions are detailed in the technical background.