Energy is the basis of our standard of living and will remain so for as long as we populate this planet. Complete electricity dependence requires building of new power plants, in particular, renewable power capacities, including large hydro power stations, which represent now approximately 22% of the installed power capacity. A substantial change in patterns of production of energy will ease the world’s transition to an era in which oil and gas are no longer the major sources of energy.

The existing types of hydroelectric installations: storage, run-of-river, and pumped-storage facilities have substantial limitations. In today's climate of increased environmental awareness, the construction of new dams is often viewed more negatively than in the past. The tidal, ocean wave and ocean currents technologies are also only approbated on the way to the extensive use.

The limitations of existing hydro power plants stimulate the development of new molecular hydro power technologies to receive clear sustainable energy in near future. The molecular technologies are based on the use of internal electric energy of elementary particles of matter: molecules, atoms, ions and electrons. To withdraw this electric energy from elementary particles many scientific methods and technical decisions based on the different physical phenomena are involved. Each new technology must be evaluated not only by its importance in advancing our society or because it makes life easier and more convenient, but by the long-term effects of it.

Among the molecular hydro power technologies and equipment the electrokinetic methods and devices for extraction of energy of moving water developing in Nizhyn Laboratories of Scanning Devices are the more promising. These technologies are based on the electrokinetic phenomena, arising up in the dispersive systems that are expressed in appearance of difference of potentials in direction of relative motion of phases under action of mechanical forces. The streaming potential is formed by isolated electrolyte, moving through porous body under pressure of water flux. A source of all these effects - the interfacial double layer of charges (DL, also called electrical double layer, EDL) - a structure that appears on the surface of an object when it is placed into a liquid. This object might be a solid particle or porous body. This electric structure consists of two parallel layers of ions. One layer (either positive or negative) coincides with the surface of the object (surface charge). The other layer is in the fluid. It is diffuse, and is called diffuse layer. Interfacial DL is usually most apparent in systems with high surface area.

The charges appeared on the phases boundary may be accumulated and used to form the electric current. To provide the stable renovation of interfacial 'double layer' of charges the outer source of energy – the pressure of moving water, for example, of river is used.

A chart of electrokinetic power system that is built in such manner concludes working body (water), electrokinetic cell, accumulator of charges and electric current inverter.

Electrolyte when going under pressure through electrokinetic cell capillaries forms on the boundary of phases a streaming potential. Charges, which arise up in a double layer, are accumulated and given to inverter to form of industrial current suitable for consumption. 

This main positive property of this chart - the direct production of electrical current. But the described chart has also a limitation – the necessity of use of moving water flux to provide stable renovation of interfacial 'double layer'.

To overcome these limitations the researchers of Nizhyn Laboratories of Scanning Devices proposed to utilize the energy of surface tension for creation of liquid flux. The power possibilities of surface layer are explicated by the work, which is necessary to transfer the molecules from the volume phase into a boundary layer. This transfer of molecules goes to the increase of surface energy – creation of surplus of energy of particles within the boundary layer in comparison with their energy in the volume of liquid. The energy of surface tension that appears on the boundary of two phases (liquid and solid) is transformed into the motion of water flux by use of the capillary structure.

The integration of electrokinetic’s and surface tension technologies gives the synergy. This collaboration can modify the power production without adversely affecting the other requirements of use.

With the purpose to increase the effectiveness of hydrodynamic capillary structure and to boost the speed of water lifting through the capillaries the team of Nizhyn Laboratories of Scanning Devices researches very thin (nano)tubes and hope to receive the capillary structures with significantly improved properties. The energy effectiveness and power capability of capillary pumped electrokinetic system may be defined by calculation of work necessary to lift (pump) the appointed mass of water on the fixed level in a unit of time. 

It is a simple case to create a laboratory example of capillary pumped electrokinetic system. But what about creating a really big industrial structure - Capillary Pumped Electrokinetic Power Plant that is able producing hundreds MW of electrical energy? For this purpose it is necessary to have enormous amount of electrolyte, a big reservoir to storage this electrolyte and capillary structure of this scale. It is a very complicate technological and ecological problem.  

The Nature gives us the wonderful examples of decision of problems: the best nature electrolyte is sea water; the sea is natural reservoir with electrolyte. 

Offshore surface tension capillary pumped electrokinetic power plant may be located on the sea platform. It concludes several artificial capillary structures. Every capillary structure is submerged by its base into the sea water. The sea water (electrolyte) is pumped by this capillary structure from sea and creates water flux. Electrolyte when going under pressure through electrokinetic cell capillaries forms on the boundary of phases a streaming potential. Charges, which arise up in a double layer are accumulated and given to inverter to form of industrial current suitable for consumption.

A failing of this scheme – the necessity of creating of complicate artificial capillary structures. Another serious failing of offshore capillary pumped electrokinetic power plant is the difficulty of energy transmission from sea platform to the seacoast. 

More promising is the scheme of Seashore Surface Tension Capillary Pumped Electrokinetic Power Plant. In this scheme as a surface tension capillary structure the natural sand is used, which is in big quantity on the seaside. Salted water is pumped from sea by sand that serves as a natural capillary structure and this water spreads around within the sand soil. When a row of electrodes are placed under soil into the flux of sea water, on the boundary of phases a streaming potential is appeared. Charges, which arise up in a double layer, are withdrawn by electrodes, accumulated and given to inverter to form industrial electric current.

The natural capillary structure (sand soil) built in accordance with described technology for pumping of sea water is ecologically safe and gives the possibility of direct production of clean industrial electrical current in near future.

 Preliminary results have improved the visibility of molecular hydroelectric power engineering and provide indications that the hydro power industry will be important to the world throughout the next century.

By Vasil Sidorov on February 18, 2010 in queltanews.com

sidorovvasil@gmail.com