Micro Hydropower is Green Power: The Basics of a Micro Hydropower System

Last Updated on June 20, 2021 by Matthew Donnelly

It is apparent that almost every human activity we have today involves the use of electricity. From heating to cooling, powering appliances, communication, transportation, food processing, and infinitely more than we could ever imagine. Needless to say, it is definitely an integral part of our existence in this modern time.

However, as we people learn by now, our ceaseless energy consumption has dire consequences to our ecosystem. As the popular saying goes, nothing comes for free. And, indeed, the exploitation of our resources is catching up to us at an incredibly alarming rate.

Nonetheless, we cannot just seem to live without electricity. Armed with the awareness and bottomless demand, experts are constantly on the hunt to a better, cleaner, and more sustainable alternative for our energy resources. And, one promisingly viable solution would be the use of a micro hydropower system. 

In this article, we will discuss all about the micro hydropower system – what it is, how it works, its applications, and the benefits and shortcomings encompassing the installation and usage of the power plant. 

1.  What is a Micro Hydropower?

To start with, let us first define what micro hydropower is.

Micro hydropower is a type of hydropower system that has a generation capacity between 5 kilowatts to 100 kilowatts. As with any other kind of hydropower system, it uses the natural flow of water to produce electricity. 

The installations are suitably located in an isolated residential property, a hobby farm or even a small community. There are also instances where the system is tapped into an electric power network wherein a net metering service is offered to consumers. 

2. What are the components of a Micro Hydropower & how does the system work?

There are a few ways to harness the energy from flowing water. However, the most commonly used for micro hydropower is the Run-of-the-River system. A run-of-the-river system is a kind of power station wherein little to no storage reservoir is required.

The initial and most important phase in the system is in the intake. This is where the water from the river, waterfall, or any form of a natural source is diverted towards the catch box for filtering off of fish, debris and other fragments. 

From the intake, the water coursed through the canal and into the forebay. The forebay serves like the holding area of the water. Underneath it is a pipeline called a penstock. In the penstock, the pressure is gradually build-up by the downward movement of the water.

After the water has traveled through the penstock, it is then tunneled down towards the turbine that is situated inside the powerhouse building. The turbine comes with a valve or a regulator to efficiently control the flow and the speed of the unit. After the water had passed through the turbines, it flows back to its natural watercourse.

Furthermore, the turbine is also responsible for converting the water flow and its pressure into kinetic energy. As a result, it carries the capacity to power the generator that is duly connected to a  series of electrical wirings. From there, the electricity is directly transmitted into a power system suitable for a single unit of a house or could even be a small community depending on the total amount produced.

A micro hydropower system can either be connected to the grid via a distribution network system, or it can also be an off-grid, stand-alone system. 

3. What are the different types of turbines, pumps, and water wheels?

The turbine, pumps, and water wheels are vital in powering a micro hydropower system. But to further drill down into the details, below are the various types and how each one differs from the other.


The specific type of hydropower turbine to be used on a certain project is based upon these parameters – the head and the flow. 

The head refers to the vertical distance of the water from the surface down towards the point where the water leaves the turbine. The head wields pressure that can potentially be converted into a usable form of energy. Thus, the higher the distance the water falls, the greater is the amount of energy produced.

On the other hand, flow pertains to the volume of water passing through a certain portion at any given time. The average amount varies from every now and then depending on the season. Extreme temperatures can cause operational constraints as it is likely to cause drought during the summer or ice formation in the winter.

Aside from the two, other factors worth considering as well include the depth of the turbine set-up, its efficiency, and, of course, the cost.

There are primarily two types available in the market today, the Impulse and Reaction Turbines.

Impulse Turbine 

This type of turbine is known for its least complex design which essentially consists of moving blades and fixed nozzles. The high-velocity water forced through the nozzles impacts the blades causing it to change the direction of the flow. The resulting shift in the momentum, or also called as an impulse, induces the rotation of the turbine.

An impulse turbine is ideally applicable for projects with high head and low flow.

Reaction Turbine

This type of turbine mainly depends on the water pressure rather than the velocity as opposed to that of an impulse turbine. The blades of this turbine require continuous contact with the water. It is also more complex and expensive thus more apt to use for large-scale hydropower plants with lower head and higher flow.


Conventional pumps can also be used instead of the typical hydraulic turbines. In this case, when the pump’s action is reversed it then works similarly like a turbine. In addition, it is also more accessible and cost-efficient thus it easily became a popular choice for consumers on a tight budget.

Nevertheless, pumps require consistent head and flow in order to deliver a decent performance. Furthermore, it is also known to be less efficient and more inclined to get worn out easily.

Water Wheel

The water wheel embodies the traditional hydropower system. You may still see some home or farm owners using this, but it isn’t as popular anymore as it used to be in the old days.  That is due to the fact that it is bulky and slower in speed thus less efficient to use for generating electricity. 

4. What are the applications of a Micro Hydropower station?

Micro hydropower stations are very flexible and can be used for different applications both for domestic or small-scale businesses. Nevertheless, its end-output is dependent on the resource’s water flow volume and velocity. Good thing though, the generated energy can be easily stored in battery banks for off-grid applications, or as support or addition to a directly connected electricity system.

Its uses can either be classified as purely consumptive or in a way productive too. 

Consumptive usage pertains to the direct utilization of the generated electricity for typical household activities. Examples include:

  • Lighting
  • Cooling
  • Heating
  • Cooking
  • Powering appliances and other devices
  • Communication

Productive usage, on the other hand, refers to the utilization of generated energy for income-producing services. Examples include:

  • Drying
  • Milling
  • Timber sawing
  • Fertilizer production
  • Textile fabrication

    5. What are the advantages of having a Micro Hydropower station?
  • Energy Resource Efficiency – It does not require an overwhelming amount of water to function. As little as two gallons per minute of water and a drop height of at least 2 feet is enough to start generating electricity. 
  • Reservoir Requirement – In the case of a run-of-the-river system, it requires little to no reservoir. That means that after the water had passed through the turbines, it is redirected back to its natural stream. Hence, causing only a minimal impact on the surrounding environment.
  • Affordability – The installation, operation, and maintenance of a micro hydropower system are likely more cost-efficient than other types of energy resources. Depending on the location and electricity requirements, the cost usually ranges T around $1,000 up to $20,000.
  • Grid Integration – Consumers have the option to be connected to a power grid to further augment its electricity supply. On the other hand, the excess load of the generated electricity can also be sent off to the grid in exchange for incentives from the utility company.
  • Environmental Impact – Hydropower is relatively renewable which means that the water is neither lost or consumed. Moreover, it does not use fossil fuels nor radioactive chemicals. Thus, it is unlikely to emit carbon dioxide or release any harmful pollutants out in the water.

    6. What are the disadvantages of having a Micro Hydropower station? 
  • Site-Specific – The suitability of a micro hydropower station basically depends on certain characteristics of the location. The site must be evaluated for its streamflow since the efficiency of hydropower is based on the head and flow of the water. In addition, it is also important to consider the distance of the power source from the intended location of use.
  • Seasonal – The stream size of a micro hydropower station fluctuates depending on the season. In some areas, the water flow is lesser during the hot summer months. As a result, power production is subsequently lessened too.
  • Expansion Limitation – In the instance where the demand for electric power increases, the option for expansion is least likely possible. That is because the amount of energy produced is essentially reliant on the existing size and flow of the water resource.
  • Local Ecological Risks – Some experts and environmentalists are concerned that the process of intentionally diverting the water flow may pose risks that interfere with the natural habitat of the fishes and other living organisms within the locality. Nevertheless, this can be effectively avoided with careful planning, construction, and diligent maintenance of the micro hydropower station.

    7. Permits and Licensing.

Now, we are on the subject of permits and licensing. 

Just because you intend to install only a small hydropower plant doesn’t mean that you are no longer obliged to conform with the local requirements. There are still a number of documents you need to comply with, although relatively fewer than that of large-scale hydropower plants. This is duly implemented in order to regulate the usage of the water resource accordingly. 

The list of requirements differs from one place to another. So make sure to inquire to your local office or agencies to assist you in the processing of necessary permits and licenses for the construction and operation of a micro hydropower station. 

So there it is! The basics of the micro hydropower system. It is a simple yet highly feasible alternative source of energy. It is a cleaner and more sustainable choice as compared to other currently leading resources like the traditional coal-fired and nuclear power plants.

It may not necessarily produce great amounts of electricity but it is ideal enough to cover the demands of a typical household or even a small community. Moreover, it is sufficient enough to lift off some of the burdens from our ecosystem brought about by the perpetual need of humans to consume electricity.

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