Marineco Project

Sea waves are a renewable energy source with the potential to produce power without harming the environment. Systems to harvest power from the sea are particularly attractive for remote coastal regions that are often far from traditional power plants.

The INCO 2' programme supported an international collaborative research project, Marineco, which aimed to develop a float wave electric power station (FWEPS) based on an innovative two-way oscillator. The Marineco project focused on the economic and societal development of remote Arctic regions without putting the wilderness area at risk. The primary objective was to exploit regional energy resources for developing environmentally friendly power-industrial technologies. In the Arctic as well as in other remote regions, sea waves constitute the most available and promising energy carrier among other renewable sources.

The project involved two EU Member States and two organisations from the Russian Federation .

One of the Russian partners, Applied Technologies Company Ltd. (ATC), was charged with constructing a model to enable simulations to take place. The challenge was to accurately describe the phys ical processes occurring in an oscillating system with two degrees of freedom. ATC employed advanced mathematical techniques to capture the essential features of the actuator.

The knowledge gathered from the simulations allowed the Marineco consortium to tweak the FWEPS prototype prior to deployment in sea-based trials.

The float wave electric power station (FWEPS) is prospectively both a commercially and an ecologically sound solution. Investigations were carried out on a twofold basis. Firstly, the aim was to assess the feasibility of the FWEPS in an Arctic context by carrying out tests of the pilot module of the offshore FWEPS as a device for sea wave energy conversion. Secondly, the project aimed to develop a methodology for use of hydrogen and oxygen produced by sea water electrolysis, followed by environmentally friendly application of these products in the metal and chemical sectors of industry.

The researchers stressed that the expenses for FWEPS production must be reimbursed during the operation period of 2 years and that total equipment lifetime was more than 10 years. Furthermore, investment costs were projected and showed the competitiveness of the FWEPS in comparison with other wave energy conversion systems.

The offshore FWEPS designed within the Marineco project is a sealed, oblong, axially symmetric capsule that can float vertically on the sea surface. Under the motion of sea waves, the FWEPS starts to oscillate along with the oscillatory system of the inner wave energy converter. The mechanical drive engaged with the oscillatory system transmits a rotary force to the shaft of the electric generator within the capsule. To increase the electric power station's efficiency for sea wave energy conversion, the latter incorporates an auxiliary energy storage unit. The FWEPS can be readily deployed in seas and oceans even under the most unpredictable conditions during seasonal or regional wave activity.

The developed module includes a mechanical oscillatory drive, an electric generator and an auxiliary energy storage unit. The oscillatory drive is required to match the time variable properties of the wave space in order to exploit sea waves more effectively. Moreover, the axially symmetric streamlined shape of the device allows better navigation with a vertical deposition of the float on the sea surface.

The innovative design facilitates sustainable operation at variable lengths, velocities and intensities of waves as well as directions of their propagation. Apart from its capability to adapt to the continuously changing external conditions, the FWIEPS is also extremely reliable. Its proper sealing offers full protection against the corrosive attack of sea water and its vapour, and thus a long life-cycle for the device.

While the FWEPS pilot module's main units and auxiliary devices were realised, physical modelling and field tests were prepared to be conducted at the laboratories of project partner Applied Technologies Company Ltd. For this purpose, a small-sized model of the FWEPS prototype was developed and evaluated at the laboratory bench and in a sea-keeping basin. Statistical characteristics of the vertical and angular motion of the buoy that carried an oscillatory system were calculated with the aim of establishing movement and power transmission sustainability.

Furthermore, a whole scope of optimum parameters for a two degrees-of-freedom oscillating model for the simulation of the FWEPS prototype was numerically calculated. More importantly, the results of physical modelling revealed the behaviour of the PWEPS device in realistic situations of irregular sea waves. These results enabled designers to assess its serviceability and efficiency.

The wave energy conversion to electricity, directly related to the intensities of irregular waves and wave-induced motions of the FWEPS device, will be finally assessed through full-scale sea trials.

Sea water is a natural electrolyte. Unlike most other water sources on our planet, it has a high level of ionic salts that are necessary for the electrolysis process to be effective. The Marineco project aimed to make electrolysis of this valuable natural resource the basis for the development of a power-industrial system for the Arctic region. The amazing feature of this ambitious plan was that all the technology, from wave power to hydrogen and oxygen production, was based on the vast volume of naturally occurring sea water surrounding the continent. Russian-based project partners at the Applied Technologies Company Ltd researched into the design of the electrolytic equipment on a laboratory scale to optimise the yield of the products. The products from the electrolysis of sea water are mainly hydrogen, oxygen and chlorine. The respective yield at the anode of gases oxygen and chlorine is dependent on factors such as the chloride ion concentration, temperature and the anode current density. All these can lead to the overproduction of a product that may not be required at that time. Although chlorine has many industrial uses such as the production of hypochlorite, a disinfectant, it is essentially a highly toxic gas. The overall aim was to limit its production in favour of oxygen.

The experiments were carried out in a single-cell model with electrode chambers separated by a membrane that allowed the exchange of ions present. The current-voltage characteristics and the content of anolyte and catolyte were defined along with the resultant quality and quantity of gases produced. Overall, this method of sea water electrolysis seemed very promising, yielding products with valuable, sustainable uses. Hydrogen of course is an energy source and is the potential fuel for fuel-cell vehicles. It is also used to make fertilisers, glass, soaps and even margarine and peanut butter. Other commercially viable products include magnesium hydroxide, which among other uses is a flame retardant and a cure for indigestion.

At a time in our planet's history when greenhouse gas production is running amok and our fossil fuel resources are running out, technology of this nature could be a valuable part of the rescue remedy.

(Source ResearchEU)

For more information: http://www.marineco.org

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