Micro hydro systems are hydroelectric power installations that typically produce up to 100 kW of power, and are mostly used to provide power to an isolated home or small communities.
In some areas micro hydro systems are used to complement for solar energy panels. This is because in the winter, when the amount of sunshine is at minimum, available hydropower is at its maximum.
Micro hydro systems unlike large hydropower plants usually do not have a dam or reservoir because these systems compared to large hydropower plants require minimal flow of water to be available year-round.
Micro hydro systems are very efficient because they require a very small amount of flow to generate electricity (around two gallons per minute should be enough). They are also very reliable, and their peak energy season is during the winter when water flow is the highest.
Micro hydro systems are not connected with high costs. Generally, a micro hydropower system’s installed cost is between $4000 to $6000 per kilowatt. A fully functioning system that can power an average household costs around $20,000., depending on site electricity, requirements and location. Maintenance costs are also fairly low.
Many energy experts believe small hydro systems would be one of the best energy options for developing countries because they are connected with low costs, and last for long time.
The main disadvantage of micro hydro systems are low power in the summer months because during the summer months there is less flow. Another disadvantage is the fact that is not that easy to find the suitable site to build these projects because you need to consider many factors like stream size, flow rate, distance from the power source, etc.
Micro hydro systems use several different types of water turbines, depending on the head of water, the volume of flow, and other factors like the availability of local maintenance and transport of equipment to the site. For mountainous regions where a waterfall of 50 meters or more may be available, a Pelton wheel is mostly used. For low head installations, Francis or propeller-type turbines are used while very low head installations of only a few meters may use propeller-type turbines in a pit.
Micro hydro systems have minimal environmental impact. Still, when building these systems constructors need to be cautious to ensure there will be no damaging impact on the nearby ecosystems.