ON/OFF - Offshore Center Danmark

10 

Offshore Center Danmark 

Newsletter ON/OFF 9 

May 2007 

Editor: Peter Blach 

pb@offshorecenter.dk 

Subscription: Berit Christensen 

bc@offshorecenter.dk 

Graphic production: 

Jan C Design & Kommunikation 

Printing: 1000 

Wave Energy – an 

Emerging Market? 

Harvesting energy from offshore is a Danish speciality. Since 

the first Danish, and also the first Northern Sea, production of oil 

was initiated in 1971 (the Dan field), and the first offshore wind 

farm in the World was constructed (Vindeby) in 1991, Denmark 

has proved itself a key player on the global offshore market. Currently, 

a new segment to the offshore energy sector is on the rise 

with Denmark taking the lead – wave energy. 

The potential for wave energy is vast. Studies have shown that 

the global energy demand can be covered from extraction of 

0.1% of the total energy available in the Earths oceans. The map 

on the next page shows the energy content at different locations. 

As seen, North Western Europe has quite a high energy content. 

Cont. page 2 

Newsletter to the offshore 

industry in Denmark 

ON/OFF 

Wave Energy – an Emerging Market? .... 1 

Converting Wave Energy 

is a Challenge ..................................... 3 

Wave Energy is an emerging renewable 

Energy Source with a big Potential ......... 6 

Offshore Wave Energy ......................... 8 

Poseidon’s organ ...............................10 

Energy on Demand .............................12 

Design of Access Platforms 

for Offshore Windturbines ....................13 

Short News ........................................14 

EU Funding of Research within Wave 

Tidal and Wind Energy ........................16 

www.offshorecenter.dk

Welcome 

Cont. from page 1 

Over the years several ideas for devices So far only a few instances of commercial 

Welcome to the 10th issue of ON/OFF, the newsletter 

from Offshore Center Danmark to the Danish 

to extraction of wave energy have been 

designed. Countries like Japan, the United 

devices have been installed around the 

World. These include the Pelamis device off 

offshore companies, institutions and international Kingdom and Norway have been conducting the coast of Portugal and Oscillating Water 

partners. 

research in wave energy since the 70’s. In Column devices in Scotland, India and at the 

In addition to the traditional offshore activities 

Denmark similar activities were undertaken, Azores. However, several promising new de- 

within offshore oil & gas and offshore wind, a new but were followed by a large state supported vices are now aiming for commercialisation 

segment of the offshore sector is currently on the 

rise – wave energy. Being the central organization 

for Danish offshore knowledge and competences, it 

is only natural for Offshore Center Danmark also to 

research programme carried out from 1997- 

2002. This spawned about 50 ideas for new 

devices, making Denmark the most active 

within the near future. These most notable 

include amongst others, the unique Danish 

devices Wave Star (scale 1:2 to be installed 

include wave energy in our activities, although it is region within development of wave energy, at Horns Rev in 2009) and Wave Dragon (to 

still a very small market, compared to the oil & gas 

and offshore wind markets. Offshore Center Danmark 

believes that a link could be established from 

offshore oil & gas and offshore wind technologies 

towards the wave energy field. It is one of our prime 

goals to stimulate such synergies between related 

offshore fields. 

and stimulated entrepreneurial developments 

in the years to follow. 

be installed in Wales in 2008)..n 

In the current issue of ON/OFF we have chosen 

to focus on wave energy. You will find a series 

of articles from Danish inventers of wave energy 

converters explaining some of the ideas and work 

being carried out within this area. In addition to 

wave energy this newsletter features an article 

about energy extraction from sea current as well as 

an article about the design of access platforms for 

offshore wind turbines. 

Please enjoy the articles which are accompanied 

with a list of short news from Offshore Center 

Danmark. 

Also please take time to visit our English-language 

website OffshoreBase.dk, where the Danish 

offshore companies and institutions present themselves 

to international partners. Also you may find 

information about – what is written in the media 

– which conferences are being held – and you may 

get an insight into some of the many technologically 

challenging offshore development projects 

undertaken by members. 

Future issue of ON/OFF will at times select a main 

offshore topic for closer investigation and will 

at other times be of a more general news-related 

nature. Please feel free to download previous issues 

of ON/OFF from our web-site. 

We hope you will find our newsletter of inte-rest. 

Kind regards, 

Peter Blach 

2 Offshore Center Denmark 

Newsletter ON/OFF 10 - May 2007 

AquaBuOY Wave Star 

Overtopping devices 

work by the overtopping 

principle 

where water is lead 

to a plateau above 

the natural sea level 

from where it will 

be lead through 

turbines. 

Wave Plane Wave Dragon 

Pelamis, Portugal 

Float based devices work by the 

absorber principle where floats 

help extracting the energy 

Oscillating Water Column devices contains a chamber 

where the water level changes as waves goes in and out. 

When the water level changes so does the pressure. This 

causes air to flow through the turbine generating electricity. 

Oscillating Water Column, Islay, Scotland

The map shows the potential 

for wave energy. 

Numbers indicate kW / m of 

crest length. 

SeaGen 

SeaFlow, North Devon, UK 

Closely related to wave energy is energy 

from sea and tidal currents. Examples 

of devices within this category include 

the SeaFlow and SeaGen from British 

company Marine Current Turbines. These 

works by blades being rotated by sea/tidal 

current. Additionally, Danish company 

Modus 2 is currently looking into the 

potential of energy from sea currents. 

Converting Wave Energy 

is a Challenge 

By Povl-Otto Nissen, Povlonis Innovation, 

Ribe, Denmark, http://www.povlonis.dk 

There is plenty of energy in ocean waves, but 

of rather low quality. Therefore it is a challenge 

to find ways to concentrate and convert 

it into more useful forms of energy, such as 

electricity. 

One of the challenges in producing electricity 

from waves is that, in spite of strong 

forces in action where waves are hitting, 

the movements in the wave crests are rather 

slow. Bigger wave heights also 

give longer wave lengths and 

periods of time between the 

energy bursts. Approximately 

with a factor of 20, but it is 

not quite linear. It means that 

the power in watt is rather low 

and not much to go for, unless 

you build a plant covering a 

big area and try to accelerate 

the movements by some 

sort of gearing or temporary 

storing. Also, it is necessary 

to find ways to smoothen out 

the irregularity of natural waves, and collect 

as much as possible to run a turbine and a 

generator. 

The state of art in wave energy converters 

can be summarized to quite a few different 

types: Oscillating water Columns (OWC), 

overtopping systems, float based plants with 

different kinds of power take off and both 

vertical and horizontal wave rotors, not to 

mention tidal and sea-drift plants. 

The principle of the OWCs is to use the water 

surface as a piston for making changes in 

air pressure in a closed but downward open 

chamber, and then put an air turbine in the 

chamber wall. This type has not been attractive 

to Danish inventors, although some of 

them work with air pressure caused by the 

waves. Countries with shore lines of cliffs 

have a better potential for that type. 

Two types of converters using overtopping 

to collect the energy have been developed by 

Danish inventors, and are now being tested 

in open sea. They are the “WavePlane” 

(Bølgehøvl) and the “Wave Dragon”. Both 

are floating for anchor. Both have power 

input from grasping the wave crests and are 

converting the energy, when the water by 

gravity goes back to sea level. WavePlane is 

cutting the waves into layers, which causes a 

whirling flow in a horizontal channel in the 

plant. Wave Dragon collects the water from 

the wave crests over a ramp to a temporary 

storing basin on the plant. This water seeks 

Testsite at Nissum Bredning 

back to sea level through vertical cylinders 

with turbines and generators. The Dragon 

has parabolic arms to optimise the wave 

heights just in front of the ramp. 

The float-based types can be categorised in 

different types of converting process and 

power take off: The first Danish big scale 

plant of this type was the Point Absorber, In 

the first version the float was driving pumps 

and a turbine in a chamber on the sea bed. 

The power conversion is now changed to 

take place in the float itself with the piston 

fastened to the sea bed. AquaBuOY looks 

very much like Point Absorber but have apparently 

a different converting system. 

Other float-based Danish converters can 

be seen. One type is pumping water or 

hydraulic oil through tubes and cylinders 

with valves and with a turbine somewhere 

Offshore Center Denmark 


3

in the circuit. The hydraulic liquid can only 

be looked on as a part of the transmission, 

because liquid cannot be compressed and 

used for storing of energy. Some have the 

pumping system beneath the surface and 

some over the surface. 

A converter of the latest type is WaveStar. 

Currently it is being tested in the Limfjord. 

Two parallel rows of nearly half spherical 

floats on arms are transmitting the movements 

from the waves by hydraulic pumps 

to a hydraulic turbine. This converter shows 

that it is possible to have many floats close 

to each other, without loosing much to the 

shadow affect. Behind a single float the 

waves are recovering very quickly by attraction 

of energy from the surroundings. 

It is a function according to the principle of 

Huyghens. 

An interesting combination of wind power 

and float-based wave converter is the Poseidons 

Organ. The floats are placed on a row 

like keys on an organ. This plant is floating 

by itself and has ordinary wind turbines on 

the top. Poseidons Organ is probably the 

next to be tested in a bigger scale. 

4 



Another special type of float-based 

converter is the Wave Plunger, where the 

waves cause the float to run up and down 

on a slant tower. A group of float-based 

converters consist of chains of pontoons, 

formed as plane flaps or cylindrical containers. 

The power take off is most commonly 

by hydraulic pumps on the top or 

inside the pontoons, when the limbs in the 

chain are shifting angular position to each 

other, caused by the waves. 

The last type of float-based converters to 

be mentioned this time is the WaveSpinner, 

an invention of Povlonis Innovation. The 

transmission from the float is mechanical 

and causes directly rotation of a couple of 

flywheels and a generator. The principle 

has been tested and shown to work in a 

small scale and is now waiting for investments 

to be built in a bigger scale. 

Another promising type of converters is 

the Wave Rotors. The first Dane, who got 

his wave energy converter patented, was 

the engineer Tage Basse. He invented a 

rotor with fish fin like blades, which surprisingly 

rotated horizontally in the water 

Offshore Wind Power 

Basic Course 

The course will provide insight into the common occurring technologies 

encountered in the offshore wind industry. Topics include: 

Turbine technology, foundations, environment, service 

and maintenance etc. 

May 30+31 2007 in Herning 

Read more and register at: www.offshorecenter.dk 

surface. Later was shown that a Darrieus 

rotor, known from wind technology, also 

works in water waves. A combination has 

now been built and is going to be tested in 

open sea. 

Povl-Otto Nissen concludes: “As you see 

there are a lot of possibilities for exploiting 

wave energy. None of the ongoing experiments 

have so far shown to be the ultimate 

answer to how to do it best. The special 

Danish grass-root method of improving 

new ideas worked well for the wind power 

section. We are trying to do it in this area 

too. But experimenting with wave energy 

is much more demanding and expensive 

compared to putting up some wings and a 

generator on a pole in your backyard. It is 

not easy without some sort of financial support 

right from the beginning. 

But it is of great fun.” 

WaveSpinner 

Povl-Otto Nissen explains the ideas behind 

his own wave energy converter, the 

WaveSpinner: 

“At first the possibility of collecting energy 

from waves had to be demonstrated more 

convincing. 

It was done by inventing a wave hoist and 

making a model out of every day things. 

The float was two joined beer cans. The 

transmission system was an asymmetric 

rocker arm on a tower, all made of construction 

iron band. When the movements of the 

float caused the rocker arm to tilt, a piece 

of bent fence wire turned a tooth wheel, 

which was connected to horizontal barrel. 

A weight on a string was then winded up 

on the barrel step by step. The barrel was 

prevented to run backward by another piece 

of bent fence wire. It worked. The construction 

can be used as a wave hoist on oil rigs, 

if they have the patience to wait for it. 

Next step was to organise the power take 

off. In stead of the string a bicycle chain 

was used. The weight to be lifted was tied to

the chain and lifted wave by wave to the top 

and over it. When falling down on the other 

side it turned two bicycle generators, just 

fast enough to get a small flash of light in a 

couple of bulbs. 

Next step again was to overcome the time 

gaps between the incoming wave crests to 

get a continued rotation. What about the 

principle of an old time foot driven sewing 

machine? Yes, but it has a fixed crank system, 

which is not suited for power input from 

a great variety of wave heights and different 

wave periods. How could that be solved? 

Take a look at the pictures and guess. 

The up and down movements of the float 

are transformed to a continued rotation of 

at couple of flywheels. It is double working. 

The volume and weight of the float 

can be optimised to deliver energy to the 

flywheel system twice every wave period. 

According to the law of Archemedes it is a 

question of interaction between gravity and 

the lift on the float. A PM-generator will be 

integrated in the flywheel system. (pat.nr. 

DK200100543, publ.date: 2003-1-20) 

So far a module in scale 1 to 20 has been 

built and tested with promising results. Next 

step is to build a bigger model in non corrosive 

materials to demonstrate survival in the 

very tough environments. After that it should 

be easy to combine many modules to a big 

wave electric power plant. The WaveSpinner 

could be placed on its own legs or in the combination 

with breakwaters. It could be hanging 

under bridges or on oil platforms. The 

modules could also be placed on submerged 

pontoons, connected with a horizontal plate 

to give stability and resistance.” 

Povlonis Innovation is quite a young company dealing with 

research, development and mediation 

Povl-Otto Nissen concludes: “We are convinced 

that wave power plants, contrary to 

what you often see, should consist of small 

relatively light weight but strong units, and 

then connected and combined to bigger 

plants. We are heading to demonstrate the 

feasibility of one module at first, somewhere 

in the North Sea, where 90% of the energy 

is available up to 3.5 meter wave heights and 

wave periods between 2 and 7 seconds. 

If someone in charge would find that interesting, 

let us talk about it.”n 

The manager, Povl-Otto Nissen, has been experimenting with wave energy since 1995. 

He is a physicist of education, has been headmaster of a Danish Folk High School, associate 

professor at Ribe College of Education, since year 2000 engaged in establishing the 

Poul la Cour Museum in Askov, Denmark. He is also the author of the biography of two 

scientists: “Poul la Cour og vindmøllerne” and “Röntgen og de mystiske stråler”, published 

by Polyteknisk Forlag. 

Offshore Center Denmark 5 

Newsletter ON/OFF 10 - May 2007

Wave Energy is an emerging renewable 

Energy Source with a big Potential 

By Per Resen Steenstrup, 

www.WaveStarEnergy.com 

Wave energy is an old story. People have 

tried to harness the power in waves for more 

than 100 years, without much luck, even 

though more than 500 million EUR have 

been spent worldwide on demonstrators. 

However over the last 3 to 5 years new ways 

of doing things have led to new technical 

solutions, which look so promising that 

commercialisation is now within reach. 

Wave energy is interesting, because it is an 

unlimited fairly stable energy source, which 

is placed at sea, 5 to 15 km offshore, in 

areas away from shipping lanes and fishing 

areas. At sea it does not take up much space, 

has practically no visual impact and no 

known negative environmental impact on 

the habitants of the sea. On the contrary, it 

seems to attract life as a sanctuary. 

The major technical break through has become 

a reality, mainly because of new simple 

storm protection schemes, simple basic 

designs for reliability which can deal with 

the harsh environment and system costs per 

MW, which in turn can be cost engineered 

to compete with wind turbines. The electricity 

production cost per MW is expected to 

be comparable to offshore wind turbines or 

even smaller, depending on the location. 

It is expected in the future, that offshore 

wind turbine farms can be combined with 

wave energy systems on a big scale, mainly 

due to utilization of a common high voltage 

line ashore, bringing down costs. Also wave 

energy devices dampen the waves inside an 

offshore wind farm, making the wind turbines 

more accessible with boats for more 

days per year. 

When will commercialisation 

take off on a big scale? 

There are different opinions about the 

above question. Some state beyond 2030, 

bot others including the author, believe it 

will happen much earlier, maybe 7 to 10 



Wave Star in normal operation. The converter is normally oriented towards the dominant 

wave direction. When the wave passes it produces an even energy output. 

Wave Star in storm protection mode 

years from know, due to several facts. Wave 

energy does not have to pave the same long 

route for political acceptance as wind power 

has been through. There is a very strong 

technical synergy between wind power and 

wave energy. They both use the same skills 

and manufacturing technologies, except for 

minor differences. The world market is more 

than ripe for new renewable energy sources, 

due to global warming and soaring energy 

demand.

The story about Wave Star 

Energy 

Wave Star Energy was established in October 

2003 with the purpose of commercialising 

wave energy based on the Wave Star 

concept. Since then extensive wave tank 

testing in scale 1:40 was carried out during 

2004, to optimize the basic configuration of 

the wave energy device and verify hydrodynamic 

modelling. 

In 2005 a scale 1:10 converter was designed 

and built with a hydraulic transmission 

system and built to the same standard as a 

full scale converter with the same instrumentation, 

electronic control system and 

grid connection. 

It was installed 6th of April 2006 in the 

sea at Nissum Bredning, close to Thyborøn 

in the North Western part of Jutland, in a 

wave climate, which is approximately 1/10 

of the North Sea. After extensive testing of 

all control systems, the system was put into 

daily operation on the 24th of July 2006. 

Since then the system has logged almost 

4.000 working hours by the end of December 

2006, without any major problems. The 

intention is to optimize the power output 

and gather information on reliability over 

the next two years. The site can be visited 

by appointment only and is connected to 

land with a pier. 

Funding 

Wave Star Energy is mainly privately founded. 

The family Clausen, behind Danfoss, 

is among the main investors in Wave Star 

Energy. In addition Wave Star Energy has 

received substantial PSO (Private Service 

Obligation) funding for renewable energy. 

How does the wave energy 

device work? 

The converter consists of two rows of each 

twenty floats. Forty floats in all. The floats 

are attached to a structure, which sits on 

piles. All moving parts are above water. 

The converter is normally installed so it is 

oriented towards the dominant wave direction. 

When the wave passes, the floats pump 

hydraulic energy into a common transmission 

system. Because the converter is oriented 

towards the dominant wave direction 

the floats pump energy into the transmission 

system distributed over time, which produces 

an even output to a hydraulic motor 

which drives a generator directly. 

A frequency converter locks the generator 

onto the grid. 

In a specific water depth, the highest possible 

wave, before it breaks, is 75% of the 

water depth. The lower part of the structure 

is at least the water depth above the water 

line. The wind load even in very high winds 

is negligible compared to the wave loads on 

the floats in normal operation. 

Practical tests have shown the Wave Star 

can accept waves from all directions. Crossing 

waves only produces a more uneven 

output to the grid, which is not a problem. 

Scaling of the Wave Star 

concept 

The ability to scale, in size and power, is 

very important to meet commercial kWh 

prices in the future. The current scale 1:10 

device installed in the sea is 24 m long with 

Ø 1 m floats. In 0,5 m waves it produces 

1.800 Watts. 

The scale 1:10 installation in 

the sea in Nissum Bredning 

in the North West of Jutland. 

The next scale 1:2 device for 10 m water 

depth in the North Sea is 120 m long and 

with Ø 5 m floats. In 2,5 m waves it will 

produce 500 kW. 

Full scale 1:1 device for 20 m water depth 

in the North Sea / Atlantic Ocean is 240 m 

long and with Ø 10 m floats. In 5,0 m waves 

it will produce 6 MW. 

Every time the Wave Star is doubled in size 

and the waves are doubled, the power goes 

up with a factor of 11! 

The Wave Star gets more cost efficient with 

greater depth and size. 

For the Wave Star an optimal water depth 

is between 10 to 40 m, as the converters are 

gradually scaled up in size. When organised 

in wave farms, the Wave Star is space 

efficient because it sits on piles and does 

not sway around in moorings. It is expected 

that 16 to 24 MW power capacity can be installed 

per km2, which is 2 to 3 times more 

space efficient than wind turbines. 

What are the future plans? 

In parallel with the testing over the next two 

years of the scale 1:10 converter, the design 

of the scale 1:2 500 kW device for the North 

Sea is already in progress. 

Main components like arms, floats and 

sections of the structure will be tested in 

the North Sea during 2007. A test site is currently 

under construction and will be ready 

by March 2007. In 2008 the scale 1:2 500 

kW device will be built and dry tested. In 

2009 it will be installed at Horns Rev 15 km 

West of Esbjerg and grid connected to the 

160 MW offshore wind turbine site. After a 

test period of 1 year the first 500 kW series 

production device will be released for sales 

and commercialisation begins. 



Offshore 

Wave Energy 

By Lars Christensen, Wave Dragon ApS 

An international race to develop and commercialise 

technologies that can utilise 

the abundant wave energy has accelerated 

within the last couple of years. Wave energy 

is a highly concentrated energy source, an 

order of magnitude more powerful than 

wind. About 10-50% of Europe’s electricity 

demand is ready to be supplied from 

technically available wave energy resources. 

Following two decades of mainly academic 

interests, wave energy has now also entered 

the focus of governments and investors, and 

this powerful combination of interests has 

speeded-up commercialisation and created 

a firm belief amongst producers, that a wave 

industry comparable with the wind power 

industry will emerge. 

That is, if appropriate wave energy converting 

technologies can be made commercially 

available. 

Fundamental challenges 

Wave power faces some fundamental challenges: 

• efficiently converting wave motion into 

electricity... generally speaking, wave 

power is available in low-speed (average 

wave frequency approximately one wave 

8 



every 10 seconds), high forces (more than 

1MW per meter wave front in storms) and 

motion is not in a single direction (like in 

wind). 

• constructing devices that can survive 

storm damage and salt-water corrosion. 

• low total cost of electricity 

• public acceptance, i.e. low visual impact 

and minimal impact on coastal processes 

An overwhelming variety of different technologies 

are developed these years around 

the world. Investors, developers and governments 

worldwide can agree on two things 

only: Large wave energy power plants will 

be offshore and floating technologies; as that 

is where the wave energy is, and it causes 

less visual and coastal process impacts. 

The Dragon 

One of the widely recognised leading wave 

energy technologies in the world is the 

Wave Dragon. Unlike most other devices it 

does not oscillate with the waves, it gathers 

the wave energy passively by utilising the 

Overtopping principle. The front face of the 

device is a curved ramp, oncoming waves 

surge up it, as if it were a beach. Behind 

the crest of this ramp lies a reservoir where 

the water “overtopping” the ramp which 

now has higher potential energy than the 

surrounding water. The effect of Wave 

Dragon is amplified by long reflector wings. 

Mounted to the reservoir, they channel the 

waves towards the ramp. The energy is 

extracted as the water drains back to the sea 

through low head hydro turbines within the 

reservoir. The Wave Dragon is designed as 

a floating offshore device to be placed in 

water depths above 20 m. 

Big is beautiful 

“Wave Dragon is by far the largest envisaged 

wave energy converter today” states 

Lars Christensen. Each unit will have a 

rated power of 4-15 MW depending on how 

energetic the wave climate is at the deployment 

site. “The large size brings many 

advantages” Lars Christensen continues. 

The device will respond minimally to 

waves, reducing fatigue problems. Also 

as the device is large and stable, it will be 

possible to work on board it most of the year,

which will dramatically reduce maintenance 

costs and downtime. An overtopping device 

brings also many advantages to robustness 

of the design, in particular there are no endstop 

problems as in larger seas the waves 

will wash over the platform harmlessly. 

Prototype testing in Denmark 

Wave Dragon has deployed and run a successful 

prototype wave energy power plant 

in Nissum Bredning in Northern Denmark. 

A 237 tonne all-steel built structure was 

constructed and deployed March 2003. The 

purpose of this test was to verify the overtopping 

principle, and how much water would 

overtop the structure in different sea states, 

and how much of this water we could manage 

to get through the turbines and thus converted 

into electricity. Although the power 

take off equipment is well known from river 

hydro and wind turbines, a full power train 

was installed to demonstrate the principle 

and to get hands-on experience operating 

these systems in a salt water environment. 

“Our first test series ran 16,000 hours, and 

we reached a 87% availability on the system, 

and the power conversion was larger 

than predicted from the wave tank tests and 

numerical simulations. As other offshore 

grid connected systems have been deployed 

for less than 1,000 hours only if ever, this 

was a very positive result, indeed” concludes 

Lars Christensen. 

Based on the experience from this 20 

months testing a number of the systems 

were improved and tested since April 2006. 

Future developments 

Next step is to demonstrate the system in 

a full size, i.e. a 7 MW device. This will 

be done just off South West Wales where 

at the moment a large number of surveys 

are carried out in order to hand in a formal 

application to the DTI. The plan is to deploy 

the device in 2008. This one device is the 

first in a 70 MW farm being developed in 

the Celtic Sea. The development is favoured 

by the UK Government commitment to 

develop a wave energy industry. The Wave 

Dragon project receives substantial support 

from the Welsh Government and the EU 

R&D framework programmes. 

Wave Energy 

Wave energy is generated by wind that 

passes over the open sea. The result is an 

energy concentration: The initial solar 

power level of about 1 kW/m2 is concentrated 

to an average wave power level of 70 

kW/m of crest length. This figure rises to 

an average of 170 kW/m of crest length during 

the winter and to more than 1 MW/m 

during storms. 

Wave energy is distributed un-evenly 

around the globe. In Europe wave energy 

origins from the North Atlantics mainly 

and are highest at freely exposed Atlantic 

coast lines from Norway in the north over 

the British island through to Portugal, with 

an annual average energy flux of 24 kW/m 

and upwards. 

In the North Sea the energy flux is from 5 

to 24 kW/m. 

Wave energy decreases rapidly in shallow 

water. At Horns Rev a level of approximately 

5 kW/m is found, according to 

Wave Dragon ApS. 

Following the Welsh project a 50 MW 

project is developed in Portugal where a 

high feed-in tariff system for wave energy 

is in place. 

Further general info: www.wavedragon.net 

Wave Dragon specifications for a 

7 MW device: 

Mooring: A catenary anchor multi-leg 

mooring bouy system. Type of anchor will 

depend on seabed conditions. 6-8 anchors. 

Structure: A mainly re-inforced concrete 

structure. The central floating platform is a 

131 x 97 m barge with open bottom compartments 

and hosts all power equipments 

etc. The floating level of this platform can 

be changed to meet the changing sea states 

by adjusting the air-pressure in the compartments. 

The two reflectors are 144 m long. 

Total height 17.5 m. 

Max draught: 14 m. 

Total weight 33,000 tonnes. 

Power Train: 

• 18 low-head axial propeller turbines. 

Variable speed form 0 to 250 rpm. 

• Direct-coupled Permanent Magnet Generators 

– 390 kW 

• Inverter control 

• Step-up transformer on-board. Step-up 

voltage will depend on local conditions. 

O&M: 

All maintenance will be carried out offshore. 



9

Poseidon’s 

Organ 

By Chief Executive Officer Partner 

Claus H. Sivager and Project Manager 

Torben Holm, Birch & Krogboe A/S 

Introduction 

Poseidon’s Organ is an invention, an ambition 

and a specific plan to develop and construct 

sustainable energy power plants in scale, 

output and economy surmounting all previous 

attempts to transform the oceans infinite 

resources into electricity. One single power 

plant unit is able to supply 12,500 households 

with electricity from its position in rough 

waters. The approximately 230 metres wide 

triangular power plant unit is capable of resisting 

conditions 10 kilometres off Portuguese 

and Irish coasts. Here wind conditions and 

energy rich waves create perfect conditions 

for a wave power plant, the first of its kind, 

conceptualised and designed for industrial 

energy production. Model tests and measurements 

clearly indicate Poseidon’s Organ will 

pull the wave energy out of the experimental 

research laboratory and put it among future 

sustainable energy sources. At present, a 

demonstration plant placed off the Portuguese 

coast is to verify the fine output and operation 

stability calculations and model tests already 

show, thus proving Poseidon’s Organ a very 

serious investment case – both in terms of 

future environment and in terms of economic 

return for a professional investor. 

Scientific and Technological 

Aims of the Project 

Effective Wave Energy Production 

Poseidon’s Organ is based on two patents and 

12 inventions in total. Prototypes in scale 1:25 

and 1:50 have through the support of the Danish 

Energy Board been tested and have shown 

very promising results in off-shore tanks and 

wave basins. The project is now ready for a 

test and demonstration plant at large scale. 

The idea is to build demonstration plants 

to identify and surmount possible technical 

barriers operating a plant at large scale and 

simultaneously demonstrating potential advan- 



tages and cost efficiency in energy production 

based on wave power. 

The project aims to transfer experience and 

technology from patents and model tests to 

the development of a prototype plant. The 

plant is to be located in the Atlantic Ocean off 

the Portuguese coast. Portugal is chosen due 

to favourable wave conditions, and because 

Portugal is a leading European nation within 

wave power technology. Furthermore Portugal 

has competent partners with close relations to 

the European energy market. 

The output of the demonstration plant is based 

on key figures, model calculations and mean 

data deriving from tests carried out. The plant 

must first and foremost confirm the following: 

- the ability to utilize at least 35 percent of 

the inherent energy in waves and transform 

it into electricity 

- the ability to produce a total output of 

30,000 kW on the demonstration plant 

including three windmills 

- the ability to achieve an output on wave 

power energy equivalent to 28GWh a year 

when the demonstration plant is located in 

the Atlantic Ocean off the Portuguese west 

coast 

- the ability to achieve an output from three 

windmills reaching in total 22GWh a year 

How does it work? 

Figure 1 illustrates how waves always hit the 

front of the plant. The explanation is to be 

found in the patented anchoring system. The 

front of the wave power plant is 230 metres 

wide and consists of 10 floats. The float 

absorbs the energy inherent in the waves. A 

double functioning pump then transforms the 

wave energy into water flow driving a turbine 

or generator producing electricity. It is the 

uniqueness of the float that ensures optimal 

absorption of the energy inherent in the waves. 

The design of the floats is a result of model 

calculations and numerous tests. 

Cost effectiveness/efficiency 

It is a project goal to develop a cost efficient 

technology improving competitiveness and 

acceptance of wave energy in the market for 

sustainable energy. The construction costs 

of Poseidon’s Organ are estimated at 41.5 

million EUR. 

Figure 1

The expected lifetime of the demonstration 

plant is 30 years. Seen over this period of 

time the electricity production costs deriving 

from Poseidon’s Organ are calculated at 0.04 

EUR/kWh*. It is not possible to compare 

this figure with other similar systems since 

information on development and construction 

costs, lifetime and maintenance concerning 

other systems is not accessible. 

The location of the plant has a significant 

influence on the total output from the plant. 

The wave power plant can either be placed 

close to the coast or far offshore. There is no 

doubt most energy within the waves at open 

sea, whereas the energy level diminishes the 

closer the coast. The explanation lies in the 

waves so called flux – or energy intensity 

– which diminishes by interaction with 

the sea bed. The shallower the waters the 

lower flux. Energy intensity no doubt varies 

depending on the specific location, as figure 

2 shows. 

If a wave power plant is to be an efficient 

and competitive alternative to other types of 

sustainable energy plants, it must be placed 

at open sea, but at the same time closest 

possible to the stabile land based consumption 

net. On the other hand a location at sea 

demands the plant is designed to resist salt 

water and the special weather occurring 

at open sea, including heavy storms. Most 

wave plant systems presently under development 

are placed where wave intensity is low 

precisely because they are not designed to 

withstand weather conditions in areas with 

high flux. 

Poseidon’s Organ lifts wave 

power to new levels 

Poseidon’s Organ is founded on the principle 

of swinging water columns and is designed for 

a location at open sea where wave energy intensity 

is largest. Regarding other wave energy 

systems, Poseidon’s Organ has a significantly 

higher total output, efficiency and energy 

production. The main explanation for this is a 

number of unique developments all contributing 

to significant improvement in wave 

power utilization. Poseidon’s Organ especially 

distinguishes itself by the following: 

Figure 2 

Location at sea 

The plant is designed for location at open sea 

with high wave intensity and dimensioned 

to withstand a so called 100 year wave. The 

construction is able to resist extreme weather 

conditions often occurring at open sea. 

Poseidon’s Organ is equipped with eight large 

pontoons that in collaboration with the plant 

floats prevent the construction from sinking. 

Ye a r l y m e e t i n g 

Offshore Center Danmark’s yearly meeting will take place at 

Skarrildhus on September 14, 2007 

Members of OCD are encouraged to mark their calendar and 

meet up for an interesting day. Activities include status from 

OCD, possibilities to influence OCD’s future activities, presentations 

from relevant offshore personalities and not least a possibility 

to network with co-workers in the beautiful surroundings 

of Skarrildhus. 



Energy on Demand 

By Bjarne Schou, CEO, Modus 2 

Could sea currents be 

turned into a new renewable 

source of energy? 

Modus 2, a Danish enterprise, 

invites companies, 

institutions, investment 

groups and individuals to 

form a European network 

for a closer look at the potentials 

According to Bjarne Schou in 2030 90% 

of all energy needed in Europe will be 

imported. “This represents a clear threat 

to our future and independency” Bjarne 

Schou continues. The priority of energy 

within the EU Framework Program 7 

could boost development of more renewable 

energy sources, lead to a major reduction 

of imported energy, as well as a boost 

for the offshore industry and more jobs. 

Wind, waves and tide are presently the 

best candidates as reliable renewable 

offshore sources of power. But how about 

sea currents? Sea currents are to be found 

all over, though sea currents are generally 

considered a modest source of energy. 

Results from American and South Korean 

offshore test projects reveal that 1) sea 

currents as modest as 0.6 m/sec can be 

used for energy production and 2) around 

40% of the kinetic energy stored in the 

sea currents can by present technology be 

transformed into power. 

Modus 2, a Danish research- and development 

enterprise, has taken the initiative 

to form a European network in order to 

unfold the potential in sea currents as a 

new source of energy. 

The research done on sea currents so far 

is quite limited. The attitude towards sea 

currents is comparable to wind 30 years 



ago, even though sea currents might have 

the same energy potential as offshore wind. 

At that time wind power was dominated 

by enthusiasts. Since then wind technology 

has developed into a reliable and efficient 

energy source. The same development 

could happen to sea currents over the next 

decades. 

The goal is to form a network of interested 

institutions, companies and individuals and 

from that platform set up projects under EU 

Framework Program 7 that can develop sea 

currents into another renewable and reliable 

energy source, enhancing a successful offshore 

industry boosting new companies and 

new job opportunities. 

Companies and institutions, investment 

groups and individuals with interest in sea 

currents are more than welcome to contact 

the author for more information about 

the network or the activities we intend to 

launch. 

Modus 2 is a Danish enterprise, transforming 

knowledge and innovation into development, 

employment and new possibilities 

for businesses and societies. Modus 2 is 

currently involved in projects and activities 

with focus on development of European 

network for a more efficient use of resources 

within the EU. 

Contact Information 

Modus 2 

Axeltorv 12E 

DK 1609 København V. 

www.modus2.dk / info@modus2.dk 

Photo: Tine Juel

Design of Access Platforms 

for Offshore Windturbines 

By Thomas Lykke Andersen & 

Peter Frigaard, Aalborg University 

A large number of offshore windfarms have 

been constructed, more are currently under 

construction and many more are planned. 

Therefore, a lot of research is going on 

within the design of offshore windfarms and 

their foundation. 

Aalborg University has lately investigated 

the wave run-up on a circular cylinder and 

the forces that the run-up generates on a 

horizontal platform and a conical platform 

using model tests. The tests have been carried 

out for DONG Energy as a part of the 

design of the foundations for the planned 

Horns Rev II windmill farm. 

The background for the study is the observations 

from the Horns Rev I windmill 

farm, where the wave run-up height has 

been shown to be significantly larger than 

accounted for in the design. This has led to 

damage to some of the access platforms and 

boatlanding facilities. The logical approach 

might seem to be to place the platforms 

significantly higher, but for safety reasons 

this is not possible. 

The objective for the model tests was to 

establish a design procedure to determine 

the impact pressures on the platforms, in the 

following three step procedure: 

1) Calculate the expected maximum wave 

run-up height with no platform. 

2) Use this run-up height to calculate the 

velocity at the level of the platform. 

3) Use a slamming force model to get the 

maximum pressures. 

Wave run-up has been measured in a small 

scale model using five water level gauges 

attached to the surface of the pile, cf. Fig. 

1. The gauges were placed 2 mm from the 

surface of the pile and catch the green water 

run-up, but not spray which is mainly gener- 

Measurement of waverun-up on pile. 

Fig. 2: Measurement of impact pressures for horizontal platform. 

Fig. 3: Measurement of impact pressures for conical platform. 

ated by breaking waves. These tests have 

been performed to calibrate step 1 and 2 in 

the design procedure. 

Access platforms are typically horizontal, 

but the client comes up with a conical platform 

solution, as they expected significantly 

smaller slamming forces for this structure. 

Therefore, both a horizontal platform and 

a conical platform were considered in step 

3 of the design procedure. The slamming 

forces generated were measured by pressure 

cells as shown in Fig. 2 & 3. 



13

Short News Short News Short News S 

Short News Short News News Short N 

Short News Short News News Short Ne 

Offshore Center Danmark and 

Bølgekraftforeningen cooporate 

Offshore Center Danmark and the Danish 

organization for wave energy, Bølgekraftforeningen 

(www.waveenergy.dk), have recently 

set up the frames for collaborating certain 

activities. The aim is to bring the wave energy 

sector and the traditional offshore sector 

closer together. Planned activities include a 

new ERFA group focusing on wave energy, 

a conference presenting possibilities within 

wave energy and more. 

DK/UK offshore wind network 

event 

February 28th and March 1st Offshore 

Center Danmark laid out the framework for a 

trans-national network event directed towards 

companies, institutions and authorities active 

within offshore wind. 

The world-leading region within the offshore 

wind market, Denmark and the fast-emerging 

region United Kingdom, were represented 

by 40 participants (approximately half from 

Denmark and half from the East of England) 

for the 2 day network event in Esbjerg. 



The first day introduced the market in the 2 

regions and then featured a 2 hour one2one 

meeting session, where companies from 

the 2 countries had the opportunity to meet 

each other. 50 meetings took place during 

the session and several companies achieved 

good contacts to potential new cooperation 

partners - some even laid the ground for 

concrete business contracts. 

The second day of the event featured presentation 

from key players on the Danish market 

including DONG Energy, Siemens Wind 

Power, Esbjerg Safety Consult and Survival 

Training Maritime Safety. 

The event was established as part of the 

POWER project (more info on www.offshore-power.net) 

and organized by Offshore 

Center Denmark in cooperation with our 

English partners. 

Details about the activities in the two 

countries (and the rest of the world) can be 

found on http://www.offshorecenter.dk/offshorewindfarms. 

IT for the Offshore Industry 

May 10th OCD and IT Forum Vest will put 

focus on IT in the offshore industry. Speakers 

from MultiPlus Solutions AS, Vestplan and 

Vestconsult will present IT solutions within 

areas of financial management, project management, 

planning & control and document 

management. The event takes place from 

15-18.30 in Esbjerg at Aalborg University 

Esbjerg. IT Forum Vest will host a light meal 

after the presentations. 

LNG 

LNG 

LNG 

LNG 

Maritime Development Center of Europe 

Tuesday June 12th 2007, 

LNG Conference 

Comwell Middelfart 

LNG Conference 

On June 12th Offshore Center Danmark and 

Maritime Development Center of Europe 

will set focus on the market for LNG (Liquid 

Natural Gas). Results from OCD coordinated 

development project of small scale LNG 

transportation will be presented at a conference 

in Middelfart. In addition, the conference 

will feature presentations from key 

speakers of the LNG market. 

Sub-soil Technology and 

Services Conference 

Sub-soil conference, held on 6th February 

2007, attracted a big interest of participants 

at Aalborg University Esbjerg.

hort News 

ews Short 

ws Short 

Nearly 70 participants attended this technical 

conference arranged by OCD and showed a 

great interest in technology behind oil and 

gas recovery from underground, and in this 

billion market. 

The sub-soil conference had a focus on 

seismic, drilling technology, well services, 

seabed surveys, well stimulation etc. Several 

suppliers were present at the conference to 

tell about the challenges and possibilities 

they face working down under surface. 

The conference was completed with presentations 

from the technical research institutions, 

who introduced the results from their 

projects within sub-soil. 

The presentations from the conference can 

be found on www.offshorecenter.dk. 

Members of 


A/S Oil Power 

A2SEA A/S 

ABB A/S 

Alslev Rustfri Montage A/S 

Altinex Oil Denmark A/S 

AMU-Vest 

AN Group 

Atcom ApS 

Atkins Danmark A/S 

Betech Seals A/S 

Blue Water Shipping 

Brdr. Jensen Maskinfabrik A/S 

Brüel & Kjær Vibro A/S 

BTM Consult ApS 

Carl Bro A/S 

Chevron Denmark Inc. 

COWI 

CT Offshore ApS 

Damcos A/S 

Dan-Equip A/S 

DAN-EX Electric A/S 

Danfoss Ventures 

Danish Air Transport 

Danish Marine & Offshore Group 

Danish Offshore Industry 

Dansk Gasteknisk Center a/s 

Dansk Industri 

Dansk Metal 

Dansk Svejse Teknik A/S 

Deloitte Statsautoriseret Revisionsaktieselskab 

Den Danske Vedligeholdsforening 

Det Norske Veritas 

DHI - Water & Environment 

DONG Energy 

DTU, Department of Mechanical Engineering 

Endress+Hauser 

Energistyrelsen 

EP TOOLS 

Erhvervs Akademi Vest 

Esbjerg Erhvervsudvikling 

Esbjerg Havn 

Esbjerg Kommune 

Esbjerg Offshore Base K/S 

Esbjerg Oiltool A/S 

Esbjerg Safety Consult A/S 

Esvagt A/S 

EUC Vest 

Europas Maritime Udviklingscenter 

Falck Nutec 

Fanø Kommune 

FH Montage 

Fiberline Composites as 

Fire-Protect A/S 

Fiskeri- og Søfartsmuseet 

Foga Aps 

FORCE Technology, Esbjerg 

Forskningsenheden for Maritim Medicin 

Fredericia Maskinmesterskole 

FURUNO Danmark AS 

Fyns Kran Udstyr A/S 

Gammelgaards Svejse Service – GSS 

Gardit A/S 

Germanischer Lloyd Denmark A/S 

GEUS,Danmarks og Grønlands Geologiske Undersøgelse 

Gimsing & Madsen A/S 

Gulf Offshore Leasing Denmark ApS 

H. J. Hansen Recycling Industry Ltd. 

Hempel A/S 

Hess Denmark 

HH-Consult 

Hydropower A/S 

Hytor 

IFU/IØ - The Industrialization Fund for Developing 

Countries 

JEVI A/S 

Jobcenter Esbjerg 

JobInVest ApS 

Jutlandia Terminal A/S 

Jørgen Kynde Isoleringsfirma 

Kirk Larsen & Ascanius 

Laybourn Trading & Technology, L.T. & T. 

LHJ Consult A/S 

LICengineering A/S 

Lindpro 

LINE-X Denmark A/S 

MacArtney A/S Underwater Technology 

Madsens Maskinfabrik ApS 

Maersk Contractors 

Masava Kemi ApS 

Maskinmestrenes Forening 

Metal Supply 

Ministeriet for Videnskab, Teknologi og Udvikling 

Minus 10dB 

MT Højgaard a/s 

MultiPlus Solutions AS 

Mærsk Olie og Gas AS 

Niels Winther & Co. 

NIRAS A/S 

Nordsø Elektronik A/S 

NV Engineering 

Ocean Team Scandinavia 

Odfjell Well Services A/S 

Olesen & Jensen 

Orbicon A/S 

Persolit A/S 

Peter Harbo A/S 

Phoenix International A/S 

PNE Teknik A/S 

Pon Power A/S 

Procurator Safety Denmark 

Promecon 

QA Consulting A/S 

Ramboll Oil & Gas 

Reson A/S 

ResQ A/S 

Ribe Maskinfabrik 

Rope Access Denmark 

Rovsing Dynamics A/S 

Roxtec ApS 

Sanistål A/S 

Score Danmark A/S 

Selco A/S 

Semco Maritime 

SGS Danmark A/S 

Siemens A/S 

Siemens Wind Power A/S 

Solar Offshore 

Stena Jern & Metal A/S 

STMS - Survival Training Maritime Safety 

Sturnus Engineering ApS 

SubCPartner ApS 

SubWind 

Syddansk Universitet 

Sydvestjysk Udviklingsforum 

Uniscrap, Åbenrå 

Valtor Offshore A/S 

Varde Kommune 

Vestas Offshore A/S 

Vestjysk Hydraulik A/S 

Vetco Gray Denmark 

Viking Life-Saving Equipment A/S 

Vindmølleindustrien 

VSB Industri- og Stålmontage A/S 

Welcon A/S 

Xperion ACE A/S 

YIT A/S 

Ødegaard & Danneskiold-Samsøe A/S 

Aalborg Universitet Esbjerg 

15 



The board of 

Offshore Center Danmark: 

Rambøll A/S, FORCE Technology A/S, 

Pon Power A/S, Aalborg Universitet 

Esbjerg and Esbjerg Kommune. 

Offshore Center Danmark was created 

through corporation between the Danish 

offshore industry, universities, municipalities, 

Ribe County (now part of the Region 

of Southern Denmark) and the Danish 

ministry for Research, Technology and 

Development. 


Niels Bohrs Vej 6 

6700 Esbjerg 

Tlf.+45 36973670 

info@offshorecenter.dk 

www.offshorecenter.dk 

EU Funding of Research 

within Wave, Tidal and 

Wind Energy 

EU Funding of Research within Wave, Tidal 

and Wind Energy 

On 6th April 2007 the European Commission 

adopted a proposal for a new EU programme 

for Research. The proposal accordingly 

“provides new impetus to increase Europe’s 

growth and competitiveness, recognising that 

knowledge is Europe’s greatest resource. The 

programme places greater emphasis than in 

the past on research that is relevant to the 

needs of European industry, to help it compete 

internationally, and develop its role as a 

world leader in certain sectors”. 

The following work programs are supported 

by the FP7 under the main header Cooperation 

Work Programs by themes: 

• Health 

• Food, Agriculture and Fisheries, and 

Biotechnology 

• Information and Communication 

Technologies - ICT 

• Nanosciences, Nanotechnologies, Materials 

and new Production Technologies - NMP 

• Energy 

• Environment (including Climate Change) 

• Transport (including Aeronautics) 

• Socio-Economic Sciences and the Humanities 

• Space 

• Security 

The objective of the FP 7 Energy is accordingly 

“to look into a portfolio of energy 

sources, to address the pressing challenges of 

security of supply and climate change, whilst 

increasing the competitiveness of Europe’s 

energy industries”. 

The EU Member States have earmarked a 

total of € 2.3 billion for funding the Energy 

theme over the duration of FP7. 

FP 7 Energy is divided into a number of subgroups 

with the following activities: 

• Hydrogen and fuel cells 

• Renewable electricity generation 

• Renewable fuel production 

• Renewables for heating and cooling 

• CO2 capture and storage technologies for 

zero emission power generation 

• Clean coal technologies 

• Smart energy networks 

• Energy efficiency and savings 

• Knowledge for energy policy making 

Within Renewable electricity generation, some 

consideration has been given to both wind, 

waves and tidal energy. 

The objective here is accordingly to provide 

“research into, development and demonstration 

of integrated technologies for electricity 

production from renewables, suited to different 

regional conditions where sufficient economic 

and technical potential can be identified, in order 

to provide the means to raise substantially 

the share of renewable electricity production in 

the EU. Research should increase overall conversion 

efficiency, cost efficiency, significantly 

drive down the cost of electricity production 

from indigenous renewable energy resources 

including biodegradable fraction of waste, enhance 

process reliability and further reduce the 

environmental impact and eliminate existing 

obstacles. Emphasis will be on photovoltaics, 

wind and biomass including CHP. Furthermore, 

research will aim at realising the full 

potential of other renewable energy sources: 

geothermal, thermal solar, ocean (e.g. wave, 

tidal power) and hydropower.” 

It is also possible to receive financing for oil 

& gas related research projects, but here you 

have to be a little more creative, as the theme 

has not been included directly in the energy 

program. Other collaboration projects can 

however be used, e.g. CO2 capture and storage 

is relevant for offshore oil & gas activities. 

For further information on energy projects and 

the other programs please visit: http://cordis. 

europa.eu/fp7/cooperation/energy_en.html

ON/OFF - Offshore Center Danmark

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