Hydropower is one of the cleanest sources of energy. The hydroelectric systems can range from really massive ones that can power entire states; to small ones fulfilling the needs of an individual household. But our focus is mainly on micro hydropower plants. They can be a great fit for many places by providing cheap and reliable electric supply.
What is Micro Hydropower?
Hydroelectric power plants are classified based on capacity. The pants with a capacity of over 30 MW are called Large hydropower; those with a generation capacity of less than 10 MW are called small hydropower. The one with a capacity of up to 100 KW is known as the Micro Hydropower plant.
|Large hydropower||Over 30 MW|
|small hydropower||Less Than 10 MW|
|Micro Hydropower||Up to 100 KW|
However, there is some discrepancy in this classification in different countries, but this is the most agreed-upon definition.
How Hydropower Works?
Like most sources of energy, the driving force behind hydropower is the sun. When the light from the sun falls on the surface of our planet, half of it is used to heat our planet, a quarter of it is reflected, and the rest of it is used to turn water into water vapours. These vapours end up in the atmosphere as clouds and later on come down as rain and snow that fills up the rivers and streams. This flowing water is used to rotate the turbines which produce electricity. The apparatus for power generation might vary based on the size and power output, but the principle remains the same.
Now, let’s discuss the various aspects of it.
Advantages Of Micro HydroPower
1. Low head and flow Required
The head is the height from which the water drops, and flow is the amount of water flowing. Contrary to popular belief, these requirements for a micro hydropower setup are not that big. While big generation units need a massive quantity of water, a micro hydropower plant can work with as little as 2 feet head, attainable in many places.
2. No reservoir needed
When people think about hydroelectricity, the first thing that comes into their minds is a huge reservoir containing billions of litres of water. However, this is not the case with a micro hydropower system. These systems are designed to benefit from the natural flow of water without needing any reservoir. This makes them economical and suitable for many more places.
3. Zero emission
A hydropower plant does not produce any emissions during its functioning. There might be some emissions during its construction and transportation, but these are quickly offset after a few days of operation. Once that happens, this apparatus is completely zero-emission
4. Continuous and predictable
The energy produced by a hydropower plant is fairly predictable. Unlike wind and solar power that are dependent on variable wind speed and clear and sunny sky, the hydroelectric power system relies on the water flow, which remains more or less predictable with some fluctuation during summer and winter months.
Another advantage is increased power output during the winter months due to escalated water flow. Coincidentally, the power demand is also higher during these months.
5. Little impact on ecology
Since a micro hydropower plant doesn’t involve constructing a reservoir or building massive structures, they have a minimal impact on ecology.
These plants are usually paired with environmentally positive things like watershed management and reforestation.
Moreover, using hydroelectric power and not fossil fuels, people are fighting global warming and climate change.
6. Positive socio-economic impacts
There have been many studies on the socio-economic impacts of micro-hydropower systems on rural and small communities. The electricity generation generally helps increase people’s income as they no longer spend money on fuel and batteries (source). There is also a significant decrease in people’s workload as they have to spend less time gathering firewood and carrying water.
7. Low distribution and running costs
Once the installation process is complete, the micro hydropower plants don’t require any fuel to run. There are, however, periodic maintenance required which is insignificant compared to the total benefits of the project.
When we talk about clean energy systems, hydropower lasts the longest. A micro-hydropower pant can last over 50 years! On the other hand, wind turbines last around 20 years, while solar panels can keep working for 25-30 years.
Also, there is no noticeable loss of energy generation over time.
9. Comparatively low cost
A micro-hydropower plant usually costs between $1000 to $20,000 based on the location and terrain. This might seem a bit steep, though compared to other sources like a wind turbine, which can cost between $5000 and $65,000 and even more for a residential setup, and solar panels that cost over $10,000, this system is much more economical.
According to a world bank report, the electricity cost of micro hydro is 6 cents/kWh, for wind, it is 7 cents/kWh, and 10 cents/kWh for solar power.
10. Buyback by the grids
If you are an individual who owns a micro-hydro and produces surplus energy, you can sell the additional energy back to the grid and make additional money. This process is known as Net Metering. The costs and rules can vary based on your location and local government.
For most people, this can be a great opportunity to earn some extra income.
11. Quick return on investment
Due to lower installation, maintenance and electricity generation costs, micro-hydropower plants can easily pay for themselves in a few years. This is one of the fastest return on investment compared to other sources of electricity.
12. Higher efficiency
The efficiency is the comparison of energy output compared to the input. It helps us determine how good a system is in converting energy.
The efficiency of micro-hydro is 70% to 90% which is very high compared to other sources like diesel engine (44%), thermal power (35-49%), wind turbine (45%) etc.
13. Higher capacity factor
The capacity factor is the ratio of the actual power produced by the power produced if the plant is working at full capacity.
Disadvantages Of Micro Hydropower
1. Not suitable for all locations
There are certain basic conditions needed before installing a micro hydropower system. These conditions include flow rate, output, water head, stream size and distance from the power source to the area where power is needed.
If these are not fulfilled, a micro hydropower plant will not work in that place.
2. Need expertise
Unlike many other systems, there is a limited scope of self-installation and DIY. Only professionals can only install Micro-hydro after carefully evaluating the area and calculating various factors.
3. Limited options for future expansion
The scope for future expansion is relatively low. Unlike other options like solar power, where you can add more panels to compensate for the rising power demands, there is no option available for micro-hydro.
During the summer months, due to reduced water flow, the output is comparatively low. However, the demand for power during these months is also lower, compensating for the downgraded output.
5. Environmental impact
The environmental impacts of micro-hydro are relatively low; however, certain minor issues can arise. There can be some erosion immediately downstream of turbines. The system could also generate a bit of noise. And, sometimes, it can affect the general appearance of an area.
To utilize the water flow and acquire the required land, you need permission from authorities. Most authorities demand that you prove there are no ill effects on fishing, riverbanks, flora and fauna, land drainage etc. These can be easily overcome using proper planning and excellent design. However, it can increase the cost and duration of the project.
7. Protection from debris
It would be best if you protect the turbine from debris. You are legally forbidden to throw the debris collected from the screen back into the river in most places. This considerably improves the downstream water quality, but it puts a significant expense on the operator.
If you live in an area where you have everything needed to install a micro hydropower plant, it can be a great investment. You are doing a great favour to you and the environment.