What Is Micro Hydro Power?

Micro hydro

Is a type of hydroelectric power that typically produce up to 100 kW of electricity using the natural flow of water. These installations can provide power to an isolated home or small community, or are sometimes connected to electric power networks. There are many of these installations around the world, particularly in developing nations as they can provide an economical source of energy without the purchase of fuel.[1] Micro hydro systems complement photovoltaic solar energy systems because in many areas, water flow, and thus available hydro power, is highest in the winter when solar energy is at a minimum. Micro hydro is frequently accomplished with a pelton wheel for high head, low flow water supply. The installation is often just a small dammed pool, at the top of a waterfall, with several hundred feet of pipe leading to a small generator housing.

Using water power to fight poverty

Micro-hydro power is the small-scale harnessing of energy from falling water, such as steep mountain rivers. Using this renewable, indigenous, non-polluting resource, micro-hydro plants can generate power for homes, hospitals, schools and workshops.

Practical Action promotes small-scale hydro schemes that generate up to 500 kilowatts of power. The micro-hydro station, which converts the energy of flowing water into electricity, provides poor communities in rural areas with an affordable, easy to maintain and long-term solution to their energy needs.

We have developed micro-hydro systems with communities in Peru, Zimbabwe, Sri Lanka, and Kenya. These systems, which are designed to operate for a minimum of 20 years, are usually ‘run-of-the-river’ systems.


Micro-hydro: the basics

“Run of the river” systems do not require a dam or storage facility to be constructed. Instead they divert water from the stream or river, channel it in to a valley and drop it in to a turbine via a pipeline called a penstock.

The turbine drives a generator that provides the electricity to the local community. By not requiring an expensive dam for water storage, run-of-the-river systems are a low-cost way to produce power. They also avoid the damaging environmental and social effects that larger hydroelectric schemes cause, including a risk of flooding.

Water from the river is channelled through a settling basin, which helps to remove sediment that could harm the turbine. The water then flows into the Forebay Tank where it is directed downhill through a pipe called a penstock. When the water reaches the bottom, it drives a specially designed turbine to produce the electricity.

What’s the environmental impact?

Unlike traditional power stations that use fossil fuels, micro-hydro generators have practically no effect on the environment. And because they don’t depend on dams to store and direct water, they’re also better for the environment than large-scale hydro-electric stations.

In fact, by reducing the need to cut down trees for firewood and increasing farming efficiency, micro-hydro has a positive effect on the local environment.

The power to recharge communities

Micro-hydro power can also be supplied to villages via portable rechargeable batteries. People can use these convenient sources of electricity to fuel anything from workshop machines to domestic lighting – and there are no expensive connection costs. The batteries are charged at a station in the village, thus providing the local community with a clean, renewable source of power.

For industrial use, the output from the turbine shaft can be used directly as mechanical power, as opposed to converting it into electricity via a generator or batteries. This is suitable for agro-processing activities such as milling, oil extraction and carpentry.

Micro-hydro schemes are owned and operated by the communities they serve, with any maintenance carried out by skilled members of that community. So they provide employment in themselves, as well as providing the power to re-energise entire communities.

What does it cost?

Costs are different for every case, and it is impossible to give an accurate figure without knowing the specifics of the site. From our experience, the cost varies from approximately 5 lacs to 15 lacs per installed kW, when using appropriate technologies, which are much cheaper than using conventional approaches and technolgies.