iowep (1)

Introduction

Norwegian company Intentium AS has been developing offshore floating wave power since 2007. Intentium offshore wave energy project - iowep, is the company's first wave project/converter. The company has completed several external studies of this patented wave energy device, and has recently completed model testing in a marine laboratory at Aalborg University through the EU funded FP7 project MARINET. Read more about MARINET test of iowep at AAU Denmark Intentium has its own internal wave tank at its location in Sjøparken Larvik, Vestfold.

Project design guidelines

The design guidelines for the project is as follows:

• Floating system
• Make use of the dominating wave front
• Keep mooring lines and PTO separate
• Find a robust concept for the PTO
• Have a short-time energy storage
• Ensure a favourable ratio between energy production and size of the structures
• Little or no risk of oil spill or other pollution
• Good concepts for installation, maintenance and survival of the system
• Use a control strategy for the wave oscillation, if possible

Concept and technology

The major news in the innovation is the focus on the dominant wave direction and wave crest length by use of a wider float, the use of a double acting pump, a buoyancy controlled water anchor and a PTO consisting in accumulator, water turbine and generator. Using a wider stabilized float, results in a wider wavefront being captured and hence more energy being harvested. The PTO has hydro-power similarities, and is disconnected from the moorings.

The main parts of this concept include:

1. Wide stabilized main float
2. Double-acting cylinder pump
3. Water anchor
4. Buoyancy controller of the water anchor
5. Power take-off, PTO (accumulator tank, impulse turbine, El-Generator)
6. Front buoy with the mooring system and the electrical subsea cable connections

3D CAD of 1:30 testmodel

Development Process

the iowep concept is the result of dedicated work starting two years before Intentium was founded in 2007. Before development started, it was studied wave energy projects, research and old patents in detail, and it was mapped technical problems and conflicts in relation to fisheries, coastal landscapes and marine transport. Shortly after the start-up of the company, it was set up an wave tank (external dimensions LxWxH - 6m x 1,5m x 1,5m) in order to make extensive use of model tests. Initially it was carried out experiments on simple models to test and to verify variuos principles. Further on, it was designed and assembled detailed test models in scale 1:30. For these constructions, it was modeled and assembled more than a hundred different custom and standard parts. The value of an own test facility, although a low-budget, has become very clear, as tests have been performed, the need for adjustments have been discovered - and carried out continuously.

It has been carried out external studies, including with a view to study the statistical probability of wave crest length, which is a very important parameter for this concept. A numerical simulations was conducted by SINTEF MARINTEK, focusing in both verification and optimization (November 2011) of the concept. See reports under Documents and Files. In 2012 the concept went through extensive ocean basin testing at Aalborg University, through the EU funded initiative MARINET. Results, backed up by the previous numerical simulations conducted, shows a persistent efficiency through a diversity of wave conditions.

Testing in Aalborg Deep Ocean Wave Basin through EU's fp7 MARINET

Documents and Files:

Patent

 Patent_NO20093423_Intentium-as (848.37 kB)

Scientific Reports

 2010-0330_Analysis_spatial_ocean_wave_fields_Krogstad-NTNU (3.86 MB)
 2010-0929_Wave_Crest_Analysis_Directional_Buoy_Barstow-OCEANOR (1003.94 kB)

 2011-1109_iowep_Marintek_Report-580306 (1.22 MB)

Videos