Danish Wave Energy Centre, DanWEC, located at Roshage in Hanstholm, is a resource centre and test station for the development of wave power technology. The North Sea off the coast of Hanstholm features wave conditions exactly right for testing pre commercial wave energy machines. Offering visitors a chance to see the impressive wave energy machine Wavestar at close hand, the test site which was inaugurated in 2009, has already had many visitors.
has been realized as a partnership between several stakeholders: Wave energy developers, Aalborg University, Thisted Municipality, the Port of Hanstholm, Thy Business Forum, the North Denmark Region and Green Labs DK.
It is a declared goal of the Danish Government to achieve a fossil fuel free energy supply in Denmark within a foreseeable future. To that end the Government has earmarked 25 million DKK to the development of wave energy.
Some of the best documented wave energy concepts worldwide are found in Denmark and the Danish wave energy business is groundbreaking. In order to maintain workplaces, knowhow and technology development within Denmark it is of paramount importance that test facilities are made available in Danish waters. DanWEC in Hanstholm is one step in the right direction of a future energy supply totally based on sustainable energy sources.
Compared to windpower the wave power technology is a new growth area, yet analysts predict that within the year 2025 offshore wind farms including wave power, will be ready for sale. Actual power producing offshore wave power facilities delivering energy to consumers on land are expected to be functioning in 2030.
The Partnership for Wave Power founded by the wave power business association has drawn up the following vision for the development of wave power in Denmark:
“The vision for Danish wave power technology development is to enhance the possibilities for Danish industry to sell competitive wave power technologies both internationally and nationally. The harnessing of wave power is a prerequisite for future offshore energy farms located at large sea depths. From the year 2030 the development of wave power technology must enable a cheap sustainable power supply from offshore energy parks in Denmark.”
Partners in the DanWEC Project
Wave Star A/S
The wave energy development company Wave Star A/S was established in 2003 and is now owned by Jørgen Mads Clausen, Chairman of the Board at Danfoss. Currently a Wave Star wave energy machine is being tested at DanWEC in Hanstholm.
The municipality of Thisted supports DanWEC as part of a campaign for energy saving initiatives in the region and Thisted’s overall plan of being the leading climate municipality in Denmark. With DanWEC and The National Test Centre for Large Wind Turbines in Østerild the municipality holds a good hand with regard to committing to green tech development.
The Wave Energy Research Group at Aalborg University carries out research and development within the field of wave energy. Research areas are for example offshore operational tests, tests of hydraulic models for wave power machines and numerical simulations of wave climate. The group collaborates with other universities, institutions and wave power developers.
The North Denmark Region is backing DanWEC financially with a contribution of 6.4 million DKK.
Green Labs DK
The Danish Energy Agency programme Green Labs DK is a governmental programme supporting the establishment of test stations demonstrating new climate and energy technologies. The programme supports green labs where companies and researchers may test and demonstrate new green technologies in realistic surroundings that apply to international standards. DanWEC has received 6.4 million DKK in funding from Green Labs DK.
The Port of Hanstholm
The Port of Hanstholm wishes to become a partner in developing renewable energy in the North Sea and is backing the wave power testing station at Roshage. The port supplies DanWEC with measurements concerning waves, wind velocity and water level. Wave conditions are monitored by a 1-D Wave Rider at a depth of 17.5 meters.
Developing a Test Centre for Wave Energy
Fully developed DanWEC will be offering users a variety of facilities such as a buoyed test area, anchoring, onshore cable, wave measurements and data acquisition. The centre will comprise office facilities and employees that can assist in issues like applying for establishing permissions and temporary power grid connection.
The plan is to establish a mini platform 3 kilometers offshore at approximately 25 meters depth. The platform will be in the shape of a monopile equivalent to what is used for wind turbine foundations. The test wave power machines will be attached to the platform by individual submarine cables with an onshore cable connection capable of transferring up to 3 MW.
DanWEC plans to offer users real time wave measurements based on two wave-metres placed at a depth of 25 meters and at the seabed, 3 kilometers offshore. One metre will be a Directional Waverider MkIII Datawell buoy, while the other metre, fitted in a trawl proof box at the seabed, will be an Acoustic Doppler Current Profiler. This instrument measures a variety of wave data such as the direction of wave propagation, flow rate and direction and water level. The wave metres concur with international standards as described in The International Electrotechnical Commission IEC TC 114, PT 62600-100: Power performance assessment of electricity producing wave energy converters.
Wind measurements at the test centre will be carried out by a sonic anemometer located where the wind field will suffer least possible influence by buildings. The instrument measures wind velocity and wind direction.
DanWEC offers a data acquisition system collecting data from different instruments and storing the data in DanWEC’s database to be disseminated on a web site.
The Power Potential of Wave Energy
Analysts assess the amount of energy from waves that pass through the Danish part of the North Sea every year to amount to 30 TWh. If a series of wave power facilities were to be established on a 150 kilometers long stretch 100 kilometers off the west coast of Jutland, they would produce about 5 TWh per year which equals approximately 15% of the Danish energy consumption. From a Danish point of view this makes the development of wave power more relevant as an export opportunity seeing that the potential for wave power is considerably higher other places in the world, like for example along the European Atlantic coast where the potential is more than twice as much as that of Danish waters. The wave power industry is a potentially large export and employment market with Denmark already taking a leading role in the development of technology and knowhow.
Long Term Power
Compared to wind power wave power is a relatively untapped energy source, yet wave power has certain advantages over wind power: The incorporation of wave power machines in offshore wind power farms may reduce operating costs because wave power machines benefit from a position far offshore where waves are more powerful. Wind turbines are often placed far offshore because of environmental concerns but that does not increase productivity. Wave power machines on the other hand increase productivity when located in deep waters where the waves are larger. Wave power is a more constant energy supply than wind power, because waves rise and fall at a more constant pace than the wind, enabling continuous energy production and a smooth output meaning that energy production is predictable 6-9 hours in advance. When the wind stops a wind turbine stops generating energy, while the swells from the waves continue for hours before they fade out. The predictability factor makes wave power easier and cheaper to incorporate into the power grid than power from wind turbines.
The Wave Star Wind Power Machine
Since September 2009 Wave Star A/S has been testing a wave power machine at DanWEC’s facilities in Hanstholm and since February 2010 the machine has been connected to the power grid delivering electricity to the electricity utility EnergiNet.dk.
The Wave Star machine is a full scale model with two floats, yet the commercial machines will be equipped with 20 floats. Before the facility was moved to Hanstholm a model on the scale of 1:40 was tested at Aalborg University and later a model on the scale of 1:10 was in operation at the test station in Nissum Bredning. In Hanstholm the facility is accessible via a 300 meters long walkway from the beach.
How does it work?
The harsh conditions at sea pose immense challenges for wave power machine developers coping with storms and salt water corrosion. The principle behind the Wavestar machine is that energy from the waves is harvested through two rows of floats with 10 floats each rising and falling with the up and down motion of waves. The floats measuring 5 meters in diameter are attached to 10 meter long arms. In tough weather with waves reaching heights of 8 meters or more, the floats are lifted and fixated above sea level increasing the operational reliability of the machine. All movable parts are located above sea level and the machine stands on legs secured to the sea floor. The motion of the floats is transferred via hydraulics into the rotation of a generator, producing electricity. The prototype in Hanstholm has two floats, weighs 1000 tons and generates 110 kW. The commercial machine will weigh 1600 tons and generate 600 kW.