In the Indian state of Maharashtra we use mainly a great amount of fossil fuel (ie coal) for power generation. Yet in the state’s western mountains there are hundreds of potential small hydro sites, with heads of 5-50m and flow rates of 1.5-10m3/sec. These sites have one problem: flow is not continuous, but is available for 150-180 days each year during the monsoon
Nevertheless, Maharashtra state would like to make use of these sites. Fossil fuels could be saved if local communities can use hydro generation when it is available, and connect to the grid at other times. Having power available in the wet season brings other benefits: breaks in the rain of several days can spoil the rice crop, but electricity would make it possible to pump water up to the paddy fields. There are indirect benefits in water supply, pollution reduction etc.
What models exist to set up these types of community-based projects? Can other small hydro users offer experience from which Maharashtra can learn?
The Government of Maharashtra in Mumbai is fully empowered to approve and allot hydro projects on a BOT, BOOT or ‘captive use’ basis.
With capital costs (including civil construction)
below US$1000/kW a return on equity at 16% for a
repayment of loan in a period of 12-25 years is expected. The present high costs of electrical and
mechanical equipment therefore need to be reduced to make these projects economically viable and attractive.
We would suggest:
•Using cheaper materials for components such as runners.
•Sacrificing some generator efficiency if it will allow us to reduce capital cost substantially.
•Developing the option of a greatly simplified remote control system. We observe that most remote control systems are designed for large hydro and their per kW cost is not reduced enough when they are applied to micro hydro schemes.
•Reducing and greatly simplifying civil structures and sharing maintenance tools and personnel between several schemes.
I would be glad to have information from any
reader with experience of such schemes, or any manufacturer who has suggestions to offer on reducing capital costs.