Because of shortcomings inherent in wind and solar energy, in particular the generation of uncontrollable electric energy limited by the performance of wind and solar energy generating plants it has become necessary to work out new ideas and technologies in order to achieve further progress of wind and solar power engineering. This is exactly the goal of the present project.
The innovative idea and appropriate technology developed by the authors of the project make it possible to realize such a multiplier of wind and solar energy that does not violate the energy conservation principle and at the same time ensures the conversion of wind and solar energy at a ratio greater than one (see Patent of Georgia no. 1799, 12.09.1997).
The project proposes to realize the new idea by using the water resource near the existing controllable HES, its upper pool (i.e. water storage) and lower pool and also by constructing a new lower pool with a lower level (НАК) than the level (НR ) of the HES lower pool and mounting pump units near the new lower pool. Electric power from wind and solar energy plants is supplied to the pump units which elevate water to the height НАК and which supply water to the HES water reservoir.
If the re-accumulation height НR (which is the difference between the levels of the upper and lower pools) of the accumulated water exceeds НAК, then for the ratio (НR/НК)RN whose value depends on irreversible hydraulic losses in the accumulation and re-accumulation pipelines and also on the efficiency of HES pump units and hydraulic units, then the electric energy output generated by the HES hydraulic units will be greater than the energy supplied from the pump units, i.e. we have energy multiplication.
It should be said that in countries with a mountainous relief there exist a lot of water resources, including rivers flowing in the gorges and lakes, which satisfy the condition
(НR/НК) >1.
To test the effectiveness of the proposed new idea, we have chosen the Enguri HES cascade with the upper level 150 m and the lower level 2 m. In the March-August period, the water reservoir level sharply changes from 510 m to 443 m and vice versa. Accordingly, the average water level of the reservoir is equal to 476 m.
According to estimations, the installed power of the pump units is 10.2 MWt, the annual output of generated electric power is 85.2 mill. kWt. When water is pumped out from the river Magana which is located at the height of 400 m (at a short distance of 1.6 km from the dam), with a water discharge of 8 m3/sec, the accumulation height is 110 m (НАК=510-400), while the re-accumulation value is НR=(476-2)=474 м. Accordingly, the theoretical multiplication value of wind and solar energy is 0=(НR/НК)=474/110=4.31, while, with irreversible losses taken into account, the real value of energy multiplication will be =2.94. This means that each 1 kWt-h generated by the wind and solar power units of the Enguri HES converts to 2.94 kWt-h.
Due to the energy multiplication factor, the production cost of 1 kWh generated by the energy multiplier is 0.012 USD, which is an unprecedented index worldwide.
In the proposed project, for receiving additional energy the authors of the project have also developed the innovative technologies (see Patent of Georgia no. 3735, 2004.03.18) by which the floating platform is installed on the HES water reservoir surface. Mounted on the platform will be two independent complete sets of hydraulic units, one of which will be used to supply water from the pump units, and the other from the HES upper pool.
Thus, the hydraulic units operating with a variable level ensure the use of the hydropower potential which is nowadays irreversibly lost at all controlled hydroelectric stations of the world during the water discharge from the reservoir and its replenishment with water because for the existing HES hydraulic units, water is supplied up to the current level Hj of the reservoir by pressure and not from the upper pool when the reservoir has a maximal level Hi and the lower pool level Н0 is constant. In this case, hydraulic energy converts to electric power in two steps. In the first step, the used water in both hydraulic units with variable level is discharged into the water reservoir. In the second step, the transformation of energy takes place by the traditional scheme, i.e. by means of the hydraulic units connected with the water reservoir and the pump station.
When the hydraulic units operating with a variable level are included into the energy multiplier scheme, the order of multiplication of wind and solar energy in the case of Enguri HES increases from =2.94 to 3.17 due to the electric energy additionally generated by the water flow from the pump station.
Hydraulic units operating with variable levels generate the major portion of electric power (70%) in the winter season of shallow water. With irreversible hydraulic losses taken into account, the output of generated additional electric power is 20-30% of the output of energy generated in the winter-spring period by the existing traditional hydroelectric stations of Georgia.
Despite the fact that we obtain high results due to wind and solar energy multipliers, they have, like any other wind and solar energy transformers, disadvantages. In particular, they stop functioning during the concurrent periods of the absence of wind and solar radiation.
The improvement or elimination of such a destructive situation is possible by the development and application of new energy multiplier schemes. Such schemes are also the subject of investigation in the project with the aim of establishing their efficiency.
