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Producing Hydroelectric Power

Author: Bela Kaltenekker

Small scale hydroelectric generation development

Introduction: The desire to produce one's own electrical energy has been the goal of many consumers. This comes from the hopes that people have to become independent of the commercially produced electrical power and the distribution grid. The benefits of this independence include the availability of electrical power during power outages of the commercial grid, potentially lower energy costs and the knowledge that one is in control of their own electrical energy needs.

During the last 30 or 40 years people have become more aware of the fragile nature of our environment and many forms of alternative energy have been suggested with some actually implemented. Many, or most, of the alternate energy production facilities are designed and built by huge international companies. These facilities are organised for a quick payback. of investment and generating profit. They are also built to reduce harmful emissions and protect the environment.

This article will concentrate on very small scale alternative power production. In recent years "Pico generators" are referred to for equipment that generates up to SkW of electrical power. This amount of energy is enough to power a large single family home, a small farm or small workshop, a small school or clinic. The equipment can be solar powered, wind or hydro powered there are some others.

This article will detail the design and potential of ?pico-hydro" electrical power generation. Hydro-power has been used for thousands of years. The early Greeks used hydro power to grind wheat into power over 2000 years ago. Little changed in the use of hydro power for some 1800 years. It continued to be used to grind wheat and also to move water to irrigate fields and to mill lumber.

The 18th and 19th century brought about the beginning of the industrial revolution and the discovery of electricity. With electricity came the electric light bulb, electric motors and other devices needing electric power. Hydroelectric power was developed and frequently used then for these devices because it supplied relatively stable and low cost power. Currently about 19% of the worlds energy production is by hydro-power, most by very large facilities.

Electrical considerations:

There are really no difficulties with the electrical system of a small scale hydroelectric power plant. The theory is very Well developed and has been utilized many times in many locations globally. The required equipment is readily available from many suppliers.

Hydroelectric generators are slow to respond to load changes. in a small facility that is a particular problem, both the voltage and the frequency can experience large fluctuations with changing loads and this has to be controlled - The current state of the electrical and electronic technology allows for control systems the can control the voltage and frequency with the use of resistor, capacitor and transistor circuitry.

These systems are fairly expensive. A better, less expensive, way to control voltage and liequency is to let the turbine/generator run at a constant load and speed by using some sort of variable load in conjunction of the system load.

This system can only be used if there is enough water available to run the generator continuously at a particular load level. Since a lot of water is available a series of electrical heater coils can be used as a load bank. The water can either be contained in a tank and further used as needed or the water can just be heated and released.

If a tank is used to contain the heated water a thermostatically controlled system can be developed to keep the heat coils active as needed. As the load requirement changes the number of active heat coils can be increased or reduced to keep the generator load constant.

Financial considerations:

A 5 kW power plant, running at 90% of the time, will annually produce about 39,060 kWh of electric power, at 15 cents/kWh that comes to almost $6000 per year. The installation cost of a small scale hydroelectric plant vary widely, on the order of $1500-$10,000 per kW.

Assuming a cost of $2500 per kW, total cost of $12,500 for a 5 kW plant, the payback on investment would be a little over two years. Consider a remote location, three miles from an available electrical grid that has water available for a S kW hydro-plant. The cost of installing a commercial power line also caries greatly, from $4000 to $10,000 per mile or more. In this instance a hydroelectric generating facility is very cost effective.

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