Siting a wave energy converter requires, at the very least, consideration of the water depth, the available mean energy density (kW/m) and the maximum anticipated wave height and period (survival sea state).
Many wave energy devices are designed to respond strongly in particular wave conditions. Wave energy devices of this type are generally not scalable as their performance relies upon an optimum relationship between the geometry of the device and the particular characteristics of the site.
A low energy site of 10-20 kW/m will require coverage of a larger amount of sea space in order to deliver the same power as a high energy site of 30–40 kW/m and will generally encounter a lower survival sea state. In general, a wave energy device designed for the larger sea state will not provide an economic return in the smaller sea states.
WaveNET’s flexible, array-based approach and family of device sizes allows it to be configured to suit the full spectrum of wave energy sites
The above diagrams show indicative array configurations for WaveNET Series-6 units, which are rated at 7.5kW each.
A minimum water depth of 20m is required; maximum waves are 6m significant. Only a single cable to shore is required for a WaveNET of the above dimensions, with a 1kV DC transmission voltage.
Twice the physical size of Series-6, WaveNET Series-12 units are rated at 75kW per unit, and are currently in development.
A minimum water depth of 30m is required; maximum waves are 12m significant. Again only a single cable to shore is required for a WaveNET of the above dimensions, with the transmission voltage increasing to 3.3kV DC.
The grid-scale vision – a 100MW WaveNET array, consisting of 135 WaveNET Series-24 units, rated at 750kW per unit. Series-24 units are four times the physical size of Series-6 units.
Albatern’s technology roadmap sets a target of this size of 100MW array by 2024, with a projected cost of energy of £100-150 per MWh.
At this scale WaveNET’s efficient use of sea space is an obvious advantage
Typical 3MW offshore wind turbines – for example those installed in the 280 GWh Kentish Flats wind farm – require a spacing of 700m.
It would be only possible to site a maximum of 3 of these off-shore wind turbines (giving a rated capacity of just 9MW) in the same sea area as this 100MW WaveNET array.