Terminology

Understanding Wave Power

What Wave Energy in kW/m means and how wave height and period combine to indicate swell power.

wave powerwave energyswell

Wave power, also called wave energy flux, describes how much wave energy passes through each metre of wave crest. SurfData displays this as Wave Energy in kilowatts per metre (kW/m).

What controls wave power?

  • Wave height has the strongest effect: in the simplified relationship used by the forecast, wave power scales with the square of significant wave height (Hs).
  • Wave period also matters. At the same height, a longer-period swell carries more power than shorter-period wind chop.
  • A small, short-period wind swell can have low power, while a long-period groundswell can carry considerably more energy.

How to use it

  • Higher wave power usually indicates a more powerful swell, but it does not by itself mean better surf conditions.
  • Read it alongside Hs, wave period, swell direction, wind, tide, and the spot rating to understand how that energy will translate at the beach.
  • Wave power is a summary of the incoming energy. The polar plot provides a more detailed view of how energy is distributed across directions and periods.