Developments

Technology

The WET-NZ wave energy converter is a ‘point absorber’ device with some special characteristics that enable it to extract energy from passing waves. The device is floating but the majority of it is submerged so that as much of it as possible interacts directly with the wave energy. An object immersed in a wave field is subjected to complex motions – heave (up and down), surge (back and forth) and pitch (a rolling back and forth motion). Most devices extract only a small proportion of the total energy of a passing wave. The WET-NZ device is designed to extract as much energy as possible from more than one type of motion. Click here to see an animation of the device in operation.

Deployments

Quarter-scale Testingwet-nz

Funded by the Foundation for Research, Science and Technology, the project team has undertaken extensive research leading to the fabrication and deployment of two devices in New Zealand waters: a 1/5-scale Proof-of-Concept device and a 1/4-scale prototype . The first device was deployed in both Christchurch and Wellington for short periods over two years from 2006. Its successor was first deployed in November 2009 at Taylor’s Mistake in Christchurch, where it has since spent periods of up to 82 days in open waters. Today it continues to provide the technical team with much valuable research data.

 

Half-scale TestingWET-NZ

With funding received from the NZ Government’s Marine Energy Deployment Fund, the research collaboration has also developed a 20 kW 1/2-scale device. Fabrication of the 18.4 m long prototype device was completed in June 2011 and it underwent initial trials at a temporary site off Akaroa Heads between September and December 2011, before being towed to Wellington. It will be deployed at the consented Moa Point test site roughly 2 km south of Wellington Airport in June 2012 for at leaat 2 years. 

The aim of the deployment is to transmit two years of electrical generation data to a useful load, as well as to gather as much information as possible on the interaction of the device with its receiving environment.

WET-NZ and Northwest Energy Innovations (USA) have started work on designing and building a second ½-scale device, based on the intital results from the MEDF device and wave tank tests that were carried out in Oregon State University’s wave basin in October 2011. This 2nd ½-scale device will be deployed off the coast of Oregon in September 2012.
 

Test Sites

WET-NZ has received resource consent for two sites for testing its prototype wave energy converters. One is ~4.3 km northeast of the Waitara River estuary in Taranaki, the other is roughly 2 km south of Wellington Airport. There is the potential at both of these sites to install a submarine cable that can transmit the electricity produced by the device to the shore where it can be connected to a useful load.  

Environmental Monitoring

It is important to WET-NZ that the interaction of its technology with the coastal marine area is carefully monitored and managed. Robust environmental monitoring plans have been produced for both consented sites through consultation with the Department of Conservation and the Regional Council. Baseline data collection was conducted at Moa Point in February 2011 and monitoring will continue through the 2-year operation and decommissioning of the WET-NZ equipment at the test site. Similar monitoring will be undertaken at the proposed Oregon site.

 

Commercialisation

The WET-NZ Programme will continue to develop devices with larger unit generating capacities. WET-NZ is focussed on developing a fully commercial technology to supply 3 potential markets:

  1. Utility-scale, grid-connected multi-unit arrays to supply electricity for network connection

  2. Distributed, smaller-scale devices to supply dedicated and off-grid users

  3. End-uses that include provision of drinking water in remote locations. 

The key aims of the consortium are to:

  • Demonstrate a safe, reliable and low-maintenance wave energy converter that has excellent performance characteristics (e.g., high availability and capacity factor)

  • Demonstrate a cost-competitive and robust technology, in terms of capital costs ($/kW), operating costs ($/kWh) and performance.

© 2010 PPL