The Need For Micro Hydro Electric Power Plants

"Water is the driving force of all nature." - Leonardo da Vinci

Hydro power has been in use from ancient civilizations. Hydro power was used for pounding grains and other domestic chores. From the watt range output generators of the 1880's to the 25,000 MW Three Gorges Dam in China or the 14,000 MW Itaipu in Brazil, hydro electric power generation has come long way, yet despite these huge advancements micro hydro electric generators are gaining prominence once more.

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The definition of a micro hydro varies in different countries. Generally 100 kw and less are considered as micro hydro and 100 – 1000 kw is mini hydro and 1000 kw to 30 MW is small hydro.

Hydro electric energy conversion is the most efficient since the potential head of water is directly available for rotating the turbine. There is no conversion or recycling loss as in thermal systems. It is easily available, there are no pollution hazards. This has made hydro electric the preferred method in the early history of power generation. But as the demands increased, the water availability became the point of constraint. Power generation shifted to fossil fuel based plants.

The economics of scale dictated larger capacity hydro power plants. These required larger and larger water reservoirs. Increasing population densities, increasing water requirements for human consumption and agriculture, reduced rainfall due to climate changes all put undue pressure on developing new potential large scale hydro power.

The single biggest deterrent for the development of large hydro plants is the ecological destruction. Reverine basins are agriculture lands or forest areas. As the water level rises the area inundated rises exponentially. This destroys agricultural land and forest areas. Along with this goes the livelihood and housing of the local population. Even though they can be relocated, it will never make up for non utilisation of their skills developed during a lifetime.

Micro and mini hydro plants are the answer.

Advantages of a mini or micro hydro power plant are many.

• Because of the low capacities of water required there is no necessity of large reservoirs or dams. Natural pools and even natural water flow can be used. What will be required is only a settlement basin or intake filter.
• The water carrying pipes are small. There is no destruction of the environment by constructing large penstocks.
• Advances in power electronics have made it possible to provide highcapacity inverters that can condition the output power to suit the grid and consumer conditions. The generators themselves do not require complicated controls since the basic conditioning is by the electronic circuitory.
• The smaller size can be ideal for DIY’s or domestic and remote loaction with considerable less maintenance requirements. This is Ideal for off grid living or remote villages.
• Because of the smaller sizes it is ideal for installation on a modular basis. Higher heads can have units installed in series or highercapacities can have it installed in. This gives higher redundancy, increased reliability. Manufacturers can make standardized product reducing cost.
• Can effectively utilize the water flow during the rainy season.
• Solar panel is costly and is limited due to the availability of the sunlight. Micro hydro covers this in areas where there is free flowing water.
• The power produced will be the lowest cost renewable energy source.

The disadvantages are only the small capacity and the disability for transmission over long distances.

A plethora of manufactures are ready to supply different types of micro and mini hydro power generators. Increasing government recognition and incentives will pave the way for more and more of these plants being in service.