Advance Power Conversion for Wave Energy

Advance Power Conversion for Wave Energy

WET-NZ is a multi-mode, point absorber wave energy convertor that has been developed to target the growing international market for utility scale renewable generation. Unlike other wave energy converters, the WET-NZ extracts power from both the heave (vertical) and surge (horizontal) motions of waves to maximize energy capture. WET-NZ produces power as a result of the relative rotational motion between the hull and float. The power takeoff (PTO) system is based on high pressure hydraulics and is located within the Power Pod. The initial technology development of the WET-NZ technology was conducted by Callaghan Innovation (formerly Industrial Research Limited), which is a New Zealand Crown Research Institute. Since development began in 2006, the WET-NZ technology has advanced from initial concept (TRL 1) to open ocean half-scale testing (TRL 5/6). Recognizing the potential of the US market, Northwest Energy Innovations (NWEI), which is based in Portland, Oregon (US) and is focused on commercializing wave energy technology, began collaborating with Callaghan Innovation to further develop and optimize the WET-NZ technology.


EHL’s objective is to become an exporter of power conversion systems for wave energy systems. Initially, EHL will sell power conversion systems to NWEI or other licensees of Callaghan Innovation.

Unique Selling Propositions

The proposed project will improve energy extraction efficiency and reduce capital costs through improvements to the hydraulics, float, and structural configuration. The result will be a reduction in LCOE, making it competitive with other forms of marine renewable energy.


Key advantages of the WET-NZ relative to other wave energy conversion systems include:

  • It can extract energy from all three sources of wave motion – models of the WET-NZ design show that it should be able to extract about 30% more energy than devices that extract energy from heave alone.
  • There are no end-stops restricting float motion and the active float can rotate through 360° in either direction. Because of these design features, electricity can be generated whenever the float is moving relative to the hull. In addition to increasing the survivability of the device, this design also increases the amount of energy that can be harnessed since the device can still generate power in storm conditions when other devices must shut down for survival.
  • In addition to increasing survivability and operations windows, the simple modular, floating design should result in lower capital and maintenance costs than other wave energy converters and enable smaller packing density for arrays (thus reducing lease costs and minimizing spatial constraints).
  • The mooring system utilizes slack mooring (similar to ship moorings) so that the device can rise and fall with tidal variation, minimizing vertical forces imposed on the system.
IP Strategy

The intellectual property related to the design of the power conversion technology is the property of Callaghan Innovation, which will be licensed to NWEI.

Project Status

Proof of Concept - Early prototype built