Complete electricity dependence of mankind requires building of new power plants, in particular, renewable power capacities, including large hydro power stations, solar plants, wind farm, biofuels, tidal, wave power, geothermal and other. But hopes on the peaceful coexistence of a «new» energy with a man were premature. Existing renewables have significant limitations: the construction of new dams is often viewed more negatively than in the past; the tidal, ocean wave and ocean currents technologies are only approbated on the way to the extensive use. The «forest» of wind turbines, hydro-turbines and towers of the sun thermal stations strongly remind the traditional bulk power systems that use high inertia massive mobile elements and require of periodic maintenance at all time of exploitation.

Another problem relied with the renewables – instability of working parameters of power capacity seasonally and according to weather conditions and time of days.

These instability factors stimulated the search and development of the new molecular power technologies to receive clear electric energy in near future from interaction of elementary particles of matter: molecules, atoms, ions and electrons.

Among these technologies the electrokinetic methods and devices for extraction of energy of moving water developing in Nizhyn Laboratories of Scanning Devices are very attractive. They are based on the electrokinetic phenomena that are expressed in appearance of difference of potentials in direction of relative motion of phases in the dispersive systems under the action of mechanical forces. The streaming potential is formed by electrolyte, moving through porous body. A source of all these effects - the interfacial double layer of charges - a structure that appears on the surface of an object (solid particle or porous body) when it is placed into a liquid. 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 diffuse layer is in the fluid.

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 liquid) is used.

Therefore to form a working chart of the molecular power electric generator it is necessary to integrate the next composite factors: an ionic solution of definite concentration (electrolyte), active solid body that have big surface area (porous body) and a flux of electrolyte to provide stable renovation of interfacial double layer.

The researchers of Nizhyn Laboratories of Scanning Devices proposed to utilize the energy of surface tension of liquid for creation of flux by means of the capillary structure. 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. The energy of surface tension that appears on the boundary of two phases (liquid and solid) is transformed into the motion of electrolytes flux.

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

The Nature gives us the wonderful chance of decision of problems: the best nature electrolyte is sea water; the sea is natural reservoir with electrolyte; the seashore sand which is found in big quantity on the seashore creates natural capillary structure that stimulates the motion of sea water under the action of surface tension of this ionic liquid and contributes to the renovation of the electrical charges in the double electric layer.

The main salt ions that make up 99.9% are the following: The ratios between elements are nearly constant although salinity (the amount of H2O) may vary. The density of fresh water is 1.00 (gram/ml or kg/litre) but added salts can increase this. The saltier the water, the higher its density. When water warms, it expands and becomes less dense.

Chemical ion         Valence    Part of salinity, %

Chloride C                    -1              55, 03

Sodium Na                   +1             30, 59

Sulfate SO4                  -2                7, 68

Magnesium Mg           +2                3, 68

Calcium Ca                 +2                1, 18

Potassium K                +1                1, 11

Bicarbonate HCO3       -1                0, 41

Bromide Br                  -1                 0, 19

Borate BO3                  -3                 0, 08

In other words, electricity is near us - under seashore sand and may be withdrawn by means of special facilities. 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 named facilities may become the base of the offshore surface tension capillary pumped electrokinetic power plant. The main positive property of this technology - the direct production of clean cheap electric energy. Many countries possess the great marine energy resources due to the large seashore line of this countries.

New molecular power sector is emerging technology. Follow-up studies will assess the economic issues associated with this untapped sea water resource.

By Vasil Sidorov on February 26, 2010 in queltanews.com

sidorovvasil@gmail.com