Development and validation of technical end economic feasibility of a multi MW Wave Dragon offshore wave energy converter
April 2006
European Commission Backs Wave Dragon multi Mega-Watt Project
Wave Dragon has been awarded a major R&D contract with the European Commission (contract no. 019983) to finalize design and realisation of a multi-MW Wave Energy Converter (WEC). This is the final step to deploying a single unit; which itself is the first step towards Europe’s largest Wave Farm.
Duration: April 1st 2006 to March 31st 2009 (36 months)
Grant: €2.4 million
Since March 2003 Wave Dragon ApS has successfully carried out long term prototype testing of the Wave Dragon and has gained more than 19,500 hours of operating hour experience. This makes Wave Dragon the most thoroughly tested offshore Wave Energy Converter (WEC) technology in the world.
During this intensive period of development and realization Wave Dragon has
- Proved that it really works
- Verified power generation performance
- Demonstrated power take-off technology
Partners
- Wave Dragon ApS (Denmark)
- NIRAS A/S (Denmark)
- Technical University of Munich (Germany)
- ESBI Engineering Ltd (Ireland)
- Balslev A/S (Denmark)
- Warzaw University of Technology (Poland)
- University of Wales Swansea (UK)
- Aalborg University (Denmark)
- Kössler Ges.m.b.H (Austria)
- Dr. techn. Olav Olsen a.s. (Norway)
- Wave Dragon Wales Ltd (UK)
EU Project Objectives
The project aims at developing the Wave Dragon technology from the tested all steel built 20 kW prototype to a full size composite built multi MW unit, and by comprehensive testing validate its technical and economic feasibility.
The RTD-part of the project will:
- Develop Wave Dragon’s energy absorbing structure; the low head turbine power take-off system and the control systems
- Develop cost effective construction methods and establish the optimal combination of in situ cast concrete, post-stressed reinforcement and pre-stressed concrete elements
- Develop a cost effective 250-440 kW hydro turbine system
- Demonstrate reliable and cost effective installation procedures and O&M schemes
- Establish the necessary basis for design codes / recommendations for offshore multi MW Wave Dragons
Big is beautiful…
By using natures own overtopping principle for capturing wave energy there is in fact no upper limit on device size or rated power for Wave Dragon as opposed to technologies that rely on moving bodies etc. for energy absorption (like buoys, hinged bodies and oscillating water columns).
This is yet another factor that makes Wave Dragon unique.
Wave Dragon’s competitive advantage lies in its scale and hence the capital cost; only 9 units are required to make a 100 MW power station compared to between 100 and 1000 units required by most other technologies. Wave Dragon is basically a static floating device; the few moving parts greatly improve reliability and drastically reduce maintenance costs. The concept is revolutionary, yet the design simply reapplies existing technologies proven for at least 80 years. Wave Dragon is essentially a floating hydro-electric dam.
This photo montage shows a 7MW unit deployed 3km off the coast and illustrates the low visual impact of a Wave Dragon device. Please note that it shows Wave Dragon at the highest position (for large waves) in a flat, calm sea.
Major challenges
Developers of wave energy converters face major challenges; first we have to develop machinery that can operate and survive in this very rough environment and secondly we have to optimise operation and maintenance systems to make wave power plants a viable solution. Furthermore wave energy converters compete with other renewable energy technologies; it has however become obvious that wave power can be much cheaper than, for instance, photovoltaic power and there are good reasons to believe that wave power in a few years will be a serious competitor to offshore wind power.
Research activities
The project will realize the Wave Dragon technology, developing it from the tested all steel built scale 1:4.5 prototype to a full size composite built multi MW unit, and by comprehensive testing validate its technical and economic feasibility.
The R&D activities will:
- Develop the optimal way to construct the Wave Dragon taking into account the large physical size, the facilities and skills available and also the techniques required to combine steel and reinforced concrete to make up the structural form we require
- Finalise the development of the power take-off system consisting of simplified hydro turbines, advanced inverter technology and permanent magnet synchronous generator technology in combination with an advanced control system never tested in full scale before
- Demonstrate that the Wave Dragon hull and reflectors can be constructed with a combination of reinforced concrete and steel
- Demonstrate the deployment of the full-scale device and document its basic hydraulic behaviour in relatively calm waters before the final deployment
- Develop an operation and maintenance strategy and operate a wave energy device of MW size using an advanced control system and a new innovative power take-off system
- Run an advanced test program on the device in order to gain information not only for the documentation of the behaviour but also for establishing scientific knowledge far beyond the current state of the art of today
- Assess the socio economic impact of Wave Dragon; job creation, life cycle assessment and environmental impact related to a MW size Wave Dragon
System availability
During the long term testing in a real sea environment the Wave Dragon prototype has progressed to the point where it is now producing electricity 80% of the time. This real sea testing has also proven its seaworthiness, floating stability and power production potential. Operation of the device in the harsh offshore environment has led to a number of smaller component failures, too. All of these have been investigated and technical solutions have been found, thus preventing costly (in both time and money) problems from occurring in the future.
The work done up to now has confirmed that the performance predicted on the basis of wave tank testing and turbine model tests will be achieved in a full scale pre-commercial demonstrator.
This project will develop the technological basis for a commercially viable solution to the bulk generation of renewable power and thus add to Europe’s ability to tackle the problems of security of supply and green house gas emissions.
Project structure
The project is organised into 7 operational Work Packages, each with clearly defined deliverables:
- Scaling up / Design – Development and design of full-sized power producing unit and associated sub-systems
- Construction, Manufacturing and Deployment
- Establishment of Monitoring System, Operation and Maintenance
- Design Parameter Analysis
- Power Production and Control Strategy
- Life Cycle / Environmental Impact Assessment and Socio-economic Aspects
- Dissemination and Exploitation
The entire R&D related Work Packages are covered by this project.
Work Package 2 (construction and deployment) are funded from other sources.
Expected results
The quantitative objectives referring to a 24 kW/m wave climate:
- Higher energy production of each unit to a total of 10 GWh/year resulting in a total improvement of 12%; 5% from improvement by better control system and 7% from the new power take-off system
- A reduction in the overall installation capacity cost of 5% compared with the state of the art
- A reduction in operation and maintenance cost of 5%
The test program will demonstrate the availability, power production predictability, power production capability and medium to long term electricity generation costs of €0.052/kWh in a wave climate of 24kW/m, which can be found relatively close to any major part of the European Atlantic coast. In a 36kW/m wave climate the corresponding cost of energy will be €0.04/kWh.