Small Sale Local Hydro Power
Workable solutions for small Hydro Projects – field examples/ technology choices
Small Hydro Projects have been initiated in various parts of the world like Indonesia, Mozambique, Tanzania, China and Sri Lanka. These projects provide workable solutions for small Hydro Projects and also benefit the community immensely. Examples include generating electricity at affordable prices to poor households. Another case in point is the electricity provided through application of these projects in assisting refugees to reconstruct their lives after tsunami disasters.
Small Hydro Projects facilitate the installation of 30-40 kilowatt micro-hydropower for supplying electricity to small villages and towns. The electricity thus generated can be sold by the villages through cooperatives specifically established for the purpose. Any profits accumulated from these Small Hydro Projects can be applied towards improving welfare of villagers through scholarships for economically backward children or low interest credits for farmers and small scale entrepreneurs.
A perfect field example is the Bungin Micro Hydro Project in Indonesia which generates 85 to 90 kilowatts of affordable electricity that is supplied to 265 households through the efforts of cooperatives that manage sale of electricity. The profit received through these initiatives is used as a “pay back” for various purposes like maintenance, promoting small scale entrepreneurs, financing scholarships for needy children as decided by the villagers.
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Types of Turbines – Use for different Head Conditions:-
Currently, water turbines are broadly categorized into two types namely impulse turbines or reaction turbines.
One clear difference between these 2 types of turbines is the way that runners function or operate. The runners in a reaction turbine are fully immersed in water. They are also enclosed in a pressure casing. The blades of the runner are angled to take advantage of the pressure differences across them which create lift forces much like those experienced on aircraft wings. The lift forces leads to the rotation of the runner.
In contrast, the runners in an impulse turbine operate in air. They are turned through jets of water that make contact with the blade. The pressurized low velocity of water is transformed into a high speed jet through the nozzles. The effect is similar to what we see in a garden hose nozzle. The appropriate alignment of the nozzle results in applying maximum force on the blades.
Within the impulse and reaction turbines, there are several variants of water turbines based on their designs such as Turgo Turbines, Pelton Turbines, Cross-flow Turbines, Francis Turbines, Propeller Turbines and Kaplan Turbines. These turbines involve different types of designs and were usually named after their inventors.
The water turbine most suitable for a particular situation will depend on factors like the amount of head (water pressure) in a specified location and whether the turbine should be suspended in water (reaction) or instead, should use jets of water (impulse). The table below summarizes the suitability of different types of water turbines.
|
High Head |
Medium Head |
Low Head |
Impulse Turbine |
Pelton, Turgo |
Cross-flow, Multi Jet Pelton, Turgo |
Cross-flow |
Reaction Turbine |
|
Francis |
Propeller, Kaplan |
Reference URL:
http://www.energybible.com/water_energy/water_turbines.html
Performance and Efficiency
Hydropower has been in existence since a long time. It is tried and tested and is often regarded as one of the most reliable and efficient sources of energy. It is also an affordable or inexpensive form of energy when compared with other types of energy such as geothermal, biomass, wind or solar energy. Modern water turbine technology has also clearly enhanced the performance and efficiency of small and micro hydro energy projects. The cost factor has also improved in recent years vis-vis other sources of energy. The range of designs now available in water turbines allow communities to take advantage of different head conditions and deploying the right type of turbine for that particular situation.
The application of small scale hydro power has also seen several success stories in countries like Sri Lanka and China. Several of these have been supported by UNIDO or United Nations Industrial Development Organization. In Sri Lanka, the electricity generated from micro-hydro projects has made a clear difference to beneficiaries. The main upside to beneficiaries is the quality of life via enhanced lighting though improved incomes have also been observed. Electric lighting is far safer than kerosene lighting. The latter is not conducive to health owing to the smoke generated and is also accident prone. Micro-hydro power has also lead to increased usage of other electrical appliances such as fans, TV and electric irons all leading to higher quality of life.
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Benefits
Hydro power is free and abundant. It is reliable, consistent and non-polluting. It is also an inexpensive form of energy that is renewable provided proper care is taken. It is a preferred source of energy since it produces no pollution and is thoroughly in sync with nature.
Global Warming: Hydro power ensures that there is no contribution to global warming since it is clean and natural energy.
Green house gas reduction: The energy generated through hydro power systems is completely free of green house gases which is not the case with other conventional sources of energy. Therefore, by enhancing the usage of hydro power energy, the world can actually reduce the green house gases and make Earth a cleaner planet.
Conventional fuels: Hydro power is a sound investment for the future since it is growing by leaps and bounds. It is renewable and adequately available on Earth provided proper care is taken to continuously renew it. This is a definite plus when compared with conventional fuels. The latter are expected to run out in the near future – some of them perhaps in our own lifetimes. Hydro power energy is clean, abundant and is thoroughly in sync with nature. Further, there is no hazardous waste produced through solar energy as is the case with coal and nuclear powered energies. To top it all, it doesn’t require any fuel to either be transported or combusted like water, gas or coal.
Barriers
Hydro power though essentially clean can several times lead to ecological and environmental concerns. For example, the construction of large dams has an impact on the environment. It could lead to dying of fish or impacting their migration. The natural flow of rivers can also be disrupted. River courses could change as a result. It could also lead to silt building up near the dam. It has often been noticed that dams used for generating hydro power have the tendency to impede the natural flow of sediments. Dams in hydro power installations could also potentially lead to catastrophes in case of their failure or breaking down as was the case with the Johnston Flood disaster that occurred on May 31, 1889.
Economic Performance
For medium heads, there is a fixed cost of about £10,000 and then about £2,500 per kW up to around 10kW – so a typical 5kW domestic scheme might cost £20-£25,000. Unit costs drop for larger schemes. Maintenance costs vary but small scale hydro systems are very reliable.
Water power can often produce between 10 and 100 times more electricity than solar or wind for the same capital investment. Also, unlike water or solar, water can be stored which can greatly improve economics.
Cost-effectiveness
The cost to install a micro-hydro system may be as low as $5000 (2006 prices), but this depends very much on your individual situation, and $10,000 is more typical.
There are some DIY micro-hydro turbine kits available for around $1000, suitable for small streams but extra costs are involved with these.
Typical costs include:
- Inlet pipes – longer or wider pipes will cost more
- Turbine and generator equipment
- Earthworks, dam or flood protection work
- A battery bank
- Electrical control system
- labor costs, including an electrician and plumber
- Electrical cables – the further the generator is from where the power will be used, the more it will cost
- Building and resource consent costs.
Maintenance costs are generally very low. The resource consent process can be costly – over $1000 in some regions.
You may be able to recover some costs by selling electricity back to your local lines company, if your property is connected and your lines company allows it.
A micro-hydro scheme is particularly worth considering if the alternative is either:
- Buying a new diesel generator, or
- Paying for an expensive connection to the local lines.
Hydro costs are very site specific and are related to energy output. For low head systems (assuming there is an existing pond or weir), costs may be in the region of £4,000 per kW (8 067.2 US$) installed up to about 10kW and would drop per kW for larger schemes.
For medium heads, there is a fixed cost of about £10,000(20 168 US$) and then about £2,500 (5 042 US$) per kW up to around 10kW – so a typical 5kW domestic scheme might cost £20-(40 336 US$) £25,000(50 420 US$). Unit costs drop for larger schemes. Maintenance costs vary but small scale hydro systems are very reliable.