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| 1.Theory |
| Theory behind energy in water is that it consists of potential energy, kinetic energy and hydraulic energy, that are commonly collectively known as hydro energy. |
| Dam-type hydropower generation |
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Conventional dam-type hydropower generation derives from potential energy, where the starting point is where water flow initiates
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| In-stream type hydropower generator STREAM |
| Our in-stream type hydropower generator converts the kinetic energy, where by efficient conversion into electricity is realized by systematically accelerating the water flow velocity and increasing the volume (mass) in the turbine. |
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Compared to the conventional head type (potential energy) hydro electricity generation that had limitations in implementation due to, for example, election of installation sites, criteria and costs, in-stream type (kinetic energy) hydro electricity generation is able to utilize the existing location’s infrastructure, adapting to criteria and budget, making them efficient renewable energy systems.
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2.Estimate electricity output calculation
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First, we need to estimate the maximum energy that can be attained at the existing waterway.
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estimation of the current electricity output capacity of the existing waterway
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Example, when the cross section of waterway dimensions are: width is 2.50m, height is 3.0m (water depth 1.50m ) quantity of water flow Q=2.50 [ ㎥/sec ] the quantity of kinetic energy estimated in the waterway (theoretical electricity generation capacity) is
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Above is the estimation of the current electricity output capacity of the existing waterway. Building on this estimation, by simple alterations to the waterway, we are able to observe higher efficiency in generation.
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Increasing the amount of electricity generation
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in general we are able to increase amount of generation of electricity by changes that either increase the volume of water Q, or raise the velocity of water V.
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For Example, accelerating the velocity of water input to the STREAM by altering the cross section or the slope angle of the existing waterway. One way to achieve this is by placing concrete or steal plates (precast concrete etc.) in the up-stream section of the existing waterway (does not need to physically attach it to the waterway; aim is to induce the cross section so as to narrow the flow passage which in turn increases flow speed. CAUTION: need to monitor the effect at the upper stream.) Thus, installating the STREAM at down stream of waterway will lead to relatively higher generation efficiency.
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estimation of the electricity output capacity after alterations to the waterway
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Additionally, by placing a precast concrete at the upper stream, reducing the cross section and slightly raising the water level at upper stream (need to check the effect on the upper most stream position) reduce the cross section area , accelerates the velocity of water flow.
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and the head can be calculated as |
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3.Cost benefit of STREAM
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| by installing one unit of our STREAM, the annual electricity generation amount is : |
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| Cost benefit (benefits in electricity saving calculated with BUY price of 1kwh @ 15yen) |
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The total cost of installing a 5kW class STREAM (varies upon different installation conditions) is approx. 6MM yen. Six to eight years amortization can be achieved (under 10 years including maintenance.) In general, the life of electrical appliances and machinery are 15-17 years. So five to seven years of net benefits can be obtained.
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This is due to the relatively stable source of energy in water, together with a generation system that can substanstially curb the initial installation cost. Longer term cost benefit may potentially overtake that of power plants.
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