Partner
  • VW-Coaching GmbH
  • Pfleiderer-Institut für
    Strömungsmaschinen
    der TU-Braunschweig
  • Harzwasserwerke GmbH
05/2004
design by l-tobe-l
animation by smund

Concept of an Economic Usage of Tidal Power

Recently, experimental underwater power plants for the exploitation of tidal currencies have been launched. Their operating principles are mostly based on the adoption of wind power plants which are meant to function underwater. On the other hand, these plants can only use one direction of the tidal current until now` and require a high level of maintenance due to the technically costly construction. Last but not least, they necessitate a high investment of about 5 millions € for an output of 300 kilowatt hours. This allows an economic power generation only in connection with a windfall of subsidies.

The problems of most tidal power plants are their high production cost and their interference with scenery, shipping, and sea live.

The new solution for these problems is Atlantisstrom

In contrast to the above, the concept of a tidal power plant, which will be presented in the following, represents a completely new development, a genuine innovation. The comparably simple construction enables energy exploitation like plant which functions on the basis of the propeller principle and comprises far less costs for production and installation. At the same time, the plant is virtually maintenance-free due to its construction, at a life of about 20 years.

  • The production costs of Atlantisstrom are far below of other comparable underwater power plants.
  • The plant can be built out of tested, prefabricated parts used for shipbuilding.
  • The unique, patented folding mechanism facilitates the exploitation of the incoming and outgoing tide automatically, without switching procedures.
  • The comparably simple construction secures a virtually maintenance- free running for a lifetime of about 20 years.
  • In order to maintain a plant which has been braced between two opposing rock faces, the following method can be used: the bracing will be released on one side of the rock face and with the help of an additional lifting power, the plant can be brought to the surface. To remove a plant from a specific location, the steel ropes can simply be cut.
  • The plant can be installed that deep under water that it is neither an impediment to shipping nor a disturbance for the spectator.
  • Atlantisstrom rotates with only 7 rpm, so it is no danger for sea live.
  • Transport from the shipyard to the construction site only requires a cargo-vessel.
  • The plant can be lowered to the sea-bed between two pontoons with the help of construction cranes.
  • By holding the plant in place on two points, it is possible to fasten it for example, on two opposing rock faces, in narrow fjords in a stable and permanent way. This is possible with the help of piles being installed into the sea-bed as well as steel ropes. No extensive efforts of laying foundations are required.
  • Atlantisstrom is the tidal power plant with the best kilowatt hours /cost relation and is not a danger for scenery, sea live or shipping.

    This drawing shows the installation of "Atlantisstrom" under a new bridge closed to Alesund Norway. (by Köster GmbH & Co. KG)

    In contrast to most remaining concepts, the plant completely disappears under water and can be installed without problems below low-tide level, e.g. by way of simply lowering and anchoring it on the seabed or between rocks. In contrast to most other plants, Atlanisstrom poses no impediment to shipping.

    In terms of effectiveness, the optimal numbers are five drop-shaped vanes of 20 meters length. Each are placed between two circular metal plates of a 8 meter diameter which are held in place by two supports. These data are valid for the first prototype which was investigated in several research papers by the Pfleiderer-Institute for Fluid Machinery of Braunschweig Technical University, Germany.

    Comparison of the power measurements at the Pfleiderer-Institute in the blocked channel (measurement Dwinger) with the one in the deepwater towing-channel Berlin and the performance accounting from the research paper by Stremlau.

    The rotating ability is due to an entirely new patented rotating mechanism of the vanes that generates a surplus of energy at the thrust faces of the vanes that are directed towards the current. It is this surplus of energy that starts up the plant and keeps it working. The electrical energy is produced by a dynamo which origins from Ships Pod propulsion.

    The plant can be built economically using conventional steel for shipbuilding preserved by silicone paint. Transport to the construction site does not require any special-purpose vehicles, but can for example be carried as deck-cargo on a cargo-vessel instead. For the construction, two lighters are needed; between these pontoons the plant can be lowered to the seabed with the help of construction cranes.

    The loading time of the animation amounts to approx. 3 minutes with ISDN
    (By clicking on the blue button, a change of current direction can be achieved)
    If you are not able to see the animation please install the Macromedia Flash-Player, which you can download from Macromedia-Homepage.

    By holding the plant in place on two points, it is possible to fasten it, for example, to two opposing rock faces in narrow fjords in a stable and permanent way without extensive efforts of laying foundations. Furthermore, the plant can also be fixed in softer seabed by means of steel tubes which can be rammed into the ground.

    The concept portrayed aims at producing energy out of the never-ending source of tides to those costs which could be competitive without subsidies. Thus, this venture is not only technically appealing, but it offers a great economic potential on growing markets which have not been opened up yet.

    In cooperation with Braunschweig Technical University and the Harzwasserwerke GmbH, a smaller prototype version (scale 1:10) was built by the Volkswagen - Coaching GmbH and has been repeatedly tested at the outlet of the Okertalsperre, a reservoir near Bad Harzburg, Germany.

    further pictures from the test run

    There was a public presentation of the prototype version in front of the power plant Romkehalle at the outlet of the Okertalsperre near Bad Harzburg on the 9th of June 2004.

    The next public presentation takes places near Tönning at the Eider (North Sea), with the help of the company Köster GmbH & Co. KG Maschinenfabrik und Gießerei Heide/Holstein. The company Köster has provided a cost estimate for the construction of a tidal power plant, fit the 300 kilowatt-class calculated by the TU Braunschweig.

    We still need investors or partners for the realization of this prototype, if you are interested please contact us.

    Further test run at the Eidersperrwerk (Northsea) under tidal conditions.

    further pictures from the test run at the Eidersperrwerk

    In 2002 a computer aided research paper for performance accounting was performed at the Pfleiderer-Institute with an Atlantisstrom tidal power plant with a 8m diameter and 20m length.
    The results are shown by the graph "Theorie (Stremlau)".

    In december 2008 the performance of an Atlantisstrom prototype with a 1m diameter and 1m length was measured at the TU-Braunschweig in a blocked channel and projected to an Atlantisstrom tidal power plant with the same size as the one in the research paper (20m length, 8m diameter)
    The results are shown by the graph "Messung PFI (Dwinger)".

    In august 2009 the prototype mentioned above was tested and measured in the 8m wide and 4m deep towing-channel for its output. The results were also projected to a tidal power plant with 20m length and 8m diameter.
    They build the graph "Messung Berlin".

    If you compare the three graphs you see that after the theoretical research paper of Stremlau, a tidal power plant with a diameter of 8m and a length of 20m would create only 25 kW at a current velocity of 2m/sec

    The measurement in the towing-channel Berlin resulted in 70 k/W of power with the same current velocity (2m/sec) and the same projection of the measured data to a rotor with 8m diameter and 20m length.

    The measurement in the blocked* channel at the TU-Braunschweig resulted in a projected performance of over 200 k/W at a current velocity of 2m/sec and a rotor of the same size mentioned above.

    The measurements mentioned above show that the performance depends on the blocking of the current by the tidal power plant.

    With a strong blocking as at the TU-Braunschweig and a tidal power plant with 8m diameter and 20m length a performance like the one shown in "Messung PFI (Dwinger)" would be expected.

    With a less strong blocking and a current velocity as in the towing-channel Berlin a performance like the one shown in "Messung Berlin" would be expected.


    Conclusion:

    The projection of the measurements proves that our tidal power plant produces several times of the performance that was assumed so far and consequently have got the best cost effectiveness of all tidal power plants.

    *Blocking: If the tidal power plant is positioned in a way, that only a little bit of water can flow past on the left and the right site of the power plant, people speak about a strong blocking. If the tidal power plant is for example positioned in a wide fjord a lot of water can flow past the left and the right site of the power plant and people speak of a slight blocking.