Alternative Energy

Alternative Energy

Alternative energy news, and information about renewable energy technologies.

Oct 26

Micro Hydro Power – Pros and Cons

Posted in Environment and Sustainability | Hydro Power

Micro HydroSmall-scale micro hydro power is both an efficient and reliable form of energy, most of the time. However, there are certain disadvantages that should be considered before constructing a small hydro power system. It is crucial to have a grasp of the potential energy benefits as well as the limitations of hydro technology. There are some common misconceptions about micro-hydro power that need to be addressed. With the right research and skills, micro hydro can be an excellent method of harnessing renewable energy from small streams. This article will attempt to outline some of the advantages and disadvantages of small scale water turbines.

Micro Hydro Pros – Advantages

Efficient energy source

It only takes a small amount of flow (as little as two gallons per minute) or a drop as low as two feet to generate electricity with micro hydro. Electricity can be delivered as far as a mile away to the location where it is being used.

Reliable electricity source

Hydro produces a continuous supply of electrical energy in comparison to other small-scale renewable technologies. The peak energy season is during the winter months when large quantities of electricity are required.

No reservoir required

Microhydro is considered to function as a ‘run-of-river’ system, meaning that the water passing through the generator is directed back into the stream with relatively little impact on the surrounding ecology.

Cost effective energy solution

Building a small-scale hydro-power system can cost from $1,000 – $20,000, depending on site electricity requirements and location. Maintenance fees are relatively small in comparison to other technologies.

Power for developing countries

Because of the low-cost versatility and longevity of micro hydro, developing countries can manufacture and implement the technology to help supply much needed electricity to small communities and villages.

Integrate with the local power grid

If your site produces a large amount of excess energy, some power companies will buy back your electricity overflow. You also have the ability to supplement your level of micro power with intake from the power grid.

Micro Hydro Cons – Disadvantages

Suitable site characteristics required

In order to take full advantage of the electrical potential of small streams, a suitable site is needed. Factors to consider are: distance from the power source to the location where energy is required, stream size (including flow rate, output and drop), and a balance of system components — inverter, batteries, controller, transmission line and pipelines.

Energy expansion not possible

The size and flow of small streams may restrict future site expansion as the power demand increases.

Low-power in the summer months

In many locations stream size will fluctuate seasonally. During the summer months there will likely be less flow and therefore less power output. Advanced planning and research will be needed to ensure adequate energy requirements are met.

Environmental impact

The ecological impact of small-scale hydro is minimal; however the low-level environmental effects must be taken into consideration before construction begins. Stream water will be diverted away from a portion of the stream, and proper caution must be exercised to ensure there will be no damaging impact on the local ecology or civil infrastructure.

Misconceptions – Myths about hydro power

Small streams do not provide enough force to generate power

The Truth: Energy output is dependant on two major factors: the stream flow (how much water runs through the system) and drop (or head), which is the vertical distance the water will fall through the water turbine.

A large water reservoir is required

The Truth: Most small-scale hydro systems require very little or no reservoir in order to power the turbines. These systems are commonly known as ‘run-of-river’, meaning the water will run straight through the generator and back into the stream. This has a minimal environmental impact on the local ecosystem.

Hydro generators will damage the local ecosystem

The Truth: Careful design is required to ensure the system has a minimal impact on the local ecology. A small amount of energy compromise may result, but this will ensure that the project does not have an effect on local fish stocks. The Environment Agency requires that stream levels must be maintained at a certain level in order to sustain the life within. Since there is no loss of water in the generation process, these requirements can easily be met.

Micro hydro electricity is unreliable

The Truth: Technology advances (such as maintenance-free water intake equipment and solid-state electrical equipment) ensure that these systems are often more reliable in remote areas. Often these systems are more dependable than the local power main.

The electricity generated is low quality

The Truth: If the latest electronic control equipment, inverters and alternators are used, the resultant power supply has the potential to be of higher quality the main electrical power grid.

Hydro power is free

The Truth: Micro power development can be cost-intensive to build and maintain. There are some fixed maintenance costs. These costs vary according to site location and material requirements.

Micro-Hydro Resources

General Microhydro Information from Picoturbine

They offer plans, books, and kits for renewable energy education and homebrew projects. Projects are available as free, downloadable do-it-yourself plans, as well as kits that include all the materials for a modest charge. Have some hard-to-find books on homebuilt renewable energy and classic renewable energy titles.

Microhydro Directory

Web directory of information about micro hydro electric power generator systems and turbines.

Microhydro Discussion Group

This Yahoo discussion group focuses on technical and non-technical aspects of run-of-river micro hydropower schemes.

Microhydro Power Calculator (and more)

A energy output calculator that makes easy work out of all the calculations required to determine the potential micro hydro resource at either an existing or a new system.

Microhydro Web Portal

Microhydro web portal is the starting point for micro-hydro related information.

Moorehead Valley Hydro

Thompson and Howe Energy Systems feature some interesting micro hydro case studies.

Other Power

Otherpower is a large information resource with a large variety of homemade small-scale renewable energy examples; including many micro hydro projects.

  • Ben

    What about freezing? Is the velocity of water in exposed 2″ PVC pipe so great that it won’t freeze in a 5-day cold snap with average temps around 20 degrees? I’m thinking of the wintertime suitability of microhydro in Kentucky.

  • Jak

    I think they also lend themselves to DIY. There seems to be way to much emphasis on turbines for some reason. For low head projects waterwheels and permament magnet generators are more appropriate and can actually be very efficient. If all you need is an extra 1kwh/day it could be a very small stream without much of a drop. Say 60gpm over a 5 foot drop.

    Nice small scale turbine projects:

    Modern waterwheels, but rather on the large side:

  • Skyler

    What about freezing X 2?

    I am planning to set a system up for Minnesota winters. That means this system will need to be reliable down to about -30F…yes that’s right, 30 degrees below zero…and we can have 1 to 3 weeks per year…sometimes in succession, of temps in this range.

    My question is…can it be done?

  • Lukas

    Good new BLOG about Powerpal Micro Hydropower.

  • peter

    For tens of thousands of years people have located their villages, then cities and megalopolises on waterways. The prime considerations for this placement of human habitation and industry were for irrigation, aquatic foodstuffs, transportation and industrial requirements. Humans also appreciated the natural beauty of bodies of water. Deep in our genetic memory, the desire to be near water is profound and must be satisfied.

    Today and especially tomorrow, it will be important to situate our villages, then small cities on bodies of water, not only for all the historic reasons but predominantly for securing power, as electricity and perhaps also for low RPM water pumping and milling.

    Electricity is the most important product in today’s world. Without it we regress. Your ideas for small scale, run of the river systems, are inspiring and wonderful in that you point the way not only towards the future, but to the salvation of mankind!

  • marina

    Of course it can be done, but this technology is more intended for use in warmer climates where energy is hard to come by. Meaning remote locations and THIRD WORLD COUNTRIES. There are many places in the world that can benefit from this technology. It’s not as if western areas where freezing temperatures occur are the only places technology can be used.

    Waterwheels are becoming more and more obsolete as time goes on because they are inefficient. Turbines are designed for efficiency, hence their emphasis. Why do you think micro hydro power is able to run on only two GPM. Designs such as the gorlov turbine has proven to be one of the most efficient tools today in drawing electricity from hydrological sources.

  • Nebreklaw01

    I keep seeing the factoid that “…micro hydro power is able to run on only two GPM”, but I can’t find a builder that will build me a turbine setup for 40 GPM and 90 psi. Is it my B.O.?


    I really appriciate you, please continue to feed us with information!

  • Louise T

    I have an old earthen dam (stream to pond to dam to stream)in upstate New York. Interested in micro-hydro. Probably requires some work on dam, which is leaking a bit from entry of spillway. Any engineers out there like this fellow in the You Tube #7 who would be interested in seeing site and advising about a) permitting b) cost and c) power generation possible?

  • sai

    I want to know the average cost of the total project and the average amount of energy the micro hydro turbines can produce. Is a drop necessary? Can a pump do the work? In places where there is no natural possibility of water drop.

  • Backwoods Monkey

    I have a creek that runs through my property it flows well year round kind of a small river but it is very flat running water almost no head but from october to may the river is raging whitewater rafters and all. I was hoping someone that might know about this type of waterway generating I don’t need much power just enough to power a very small cabin.
    Thanks for any input.

  • Pat & Mel

    We have a small stream that flows through our property with a couple of small drops. A pond that is fed by run off, that flows through the middle of the property and runs down an embankment. And a potion of the property is wet most of the year again running down an embankment to the brook. Does any of this sound like it could be used to sustain a micro-hydro setup.

    This property is also at a high point on a mountain which might also sustain some wind energy.

    Any viable input would be greatly appreciated.

    Pat & Mel

  • harvey knoll

    I have a stream that is capable of runing a 10″ sq fiberglass tube of water year round (eve tho it is runing 15′ wide and 2′ deep now.) with a 21ft drop in 300′. My highest electric bill last year was 2910kwh for a 30 day period. #1 is it possible for me to get off the grid? #2 What would you sugest? Thank you Harvey


    Micro-hydro power is sustainable,with on-going extensive research and development, I can assure that in a few years power companies will have to drop their tariffs. However I foresee multiple, unregulated sighting of turbines, such that it becomes a threat to ecology.

  • Stasulos

    Harvey! wow! 3megawatt-hours per month! This is huge! This is industrial level consumption. Are you running a factory there or something? If I were you I would start by seriously thinking about cutting the consumption, not changing the provider. The truth is that the grid is cheaper in 90% of the cases. Secondly, I would try to move consumption into night tariffs zone wherever possible. And only after the first two are exhausted I would try to generate myself.

  • Kevin Rossiter

    General rule of thumb for hydropower [head (ft)*flow (g/m)]/10. 90 psi is 200+ feet of head * 40 g/m = 8000/10= 800 watts of hydropower. 300 watts will run a normal house of 4 except for heat and A/C. Pipes should be buried to avoid freezing and potential damage from animals, etc. We sell machines all over the world.

  • PowerToSA

    Hi I live near the marsh and the is water there all year long but the water is not going anywhere it is not flowing its just static is there a way that I can use the pelton turbine to generate water from that or is there a way that I can cause the water to flow through some artificial means. Is there any one that has done this before, constructing a micro hydro system in the marsh, is it even possible?

  • Charles Cooper


    Umm, no.

    The point is you need moving water to ‘spin the wheel’ to make electricity.

  • Boneheaded1


    If you build a water tower then build a human powered conveyor to move the water up to the tower’s tank then yes you could generate electricity releasing the water from the tower back to the swamp.

    But, you would spend all day filling the tower and your life savings building the water tower and the conveyor.

    Probably better to forget about hydro-power in your case.

  • patrick andrews

    So with all this micro hydro… could it be put into an area w/ clean treated wastewater running through it? Looking into alternative energy for my wastewater plant in upper New York so any input would be appreciated.

  • Azmat A Shah

    There is power shortage in third world countries all over the globe. As a result load shedding is necessitated to overcome this shortfall. In order to meet energy demand in our homes, think of producing 5kw electricity with water turbine, availing facility like solar energy to pump water to overhead tank to create head for power generation. This can solve our power problem especially in Pakistan. The point is to convince turbine manufacturers to keep the prices to our capacity.

  • JessW

    By keeping the in stream flow changes to an appropriate minimum you can get the best in efficient renewable power production.

  • Hugh Simpson

    Just found this site and I wanted to know if there are people here that have had experience of using a fast running river instead of just a stream. We have numerous high waterfalls and a river that is one of the best kayak rivers in the SE USA.

    I manufacture dodecahedron dome homes and will be relocating my company to Tellico Plains, TN where the Tellico River is. We are coming up with a Village in a Box concept that includes my friend’s Aquaponics System called Farm in a Box.

  • Bolden

    Ok so, I’m seriously thinking of doing this. I’ve heard a lot of mumbo jumbo and I’m new so I sort of take everything with a grain of salt. Is it really that much more cost effective to go microhydro for a small single dwelling home, wood heat, (although electric heat would be nice too), not worried about a/c. and at this point single male so that helps right? what is an approximate yearly cost? thanks for your knowledge and help!

  • M.Daulat Hussain

    Small power generation is very important and essential for irrigation to forest and hilly areas where electricity supply is not available and the small power generation system will be sustainable to that places.

  • Frank

    This site may help to all.

  • magnet

    where’s the STEP BY STEP “HOW WAS IT DONE”.
    maybe its like this:
    1st you bought a generator with permanent magnet on it then dismantle it and then again take only the DYNAMO.
    2nd make a turbine
    3rd put them together
    4th install it on the river, creek etc…
    5th trial and error.
    6th ask an electrical engineer
    7th pay some one to do it

  • Freddy Akuffo

    Hi ,

    A friend of mine wants to construct a 100kw capacity mini hydro in his country to help boost power supply. Is this feasible? At what point does it stop being a micro dam? How would you go about this? Need some thoughts on this..

  • Jack

    #25 M.Daulat Hussain February 2nd, 2010 wrote: “Small power generation is very important and essential for irrigation to forest and hilly areas where electricity supply is not available and the small power generation system will be sustainable to that places.”

    When irrigation is the desire, opt for mechanical over electrical generation. I love micro hydro power as much as anyone, yet ram pump costs one-tenth what a micro hydro generator does, even before adding an electric pump. It’s also simple, centuries-plus (1774) proven technology that requires no maintenance and can be bought off-the-shelf or build your own from plumbing parts. A ram pump will operate at 15-10% efficiency, or for every eight – ten gallons running through it, it pumps one gallon up hill.

  • Tony B

    Has anyone ever heard of micro hydro turbines used in storm sewer or water main pipes rather than above ground? Just curious if the technology exists.

  • Jack

    #30 Tony B., yes.
    Google “”Riverside in-pipe turbine project first of its kind”, and you’ll find the February 25, 2010 press release including pictures of this 2-7 kw turbine generator powered by water flow within a 48-inch pipe.

  • Rich

    There is some technology on a large scale.
    I have been working on it at a smaller scale.

  • Tony B

    RE: #31

    Thanks Jack, that’s exactly what I was trying to find.

  • Rick

    Could a small scale hydro system be set up on a recirculating type system, such as recirculated grey water?

  • Ronny

    I have an enjoyable situation- unique with few exceptions, in that I own an old grits mill pond (aprx. 12 acres) with a measured water flow of aprx. 750GPM and head (depth at my spillway) aprx. 16 feet. I am reasonably certain some type of power generation system could be used and installed here (house is aprx. 200 feet of spillway), but can’t find anyone able to be of realistic assistance. Not int’d in selling power back to power co. (no win situation), but to supply or supplement my own use. any help out there? Thanks

  • Toby

    Man made Artesian Water Well. Free flows a few thousand vertical feet down from the surface of the well bore up eight inch casing and flows 25 gallons a minute and builds up to 100 PSI.

    I wonder if I could fill a water tower and allow less flow down a pipe to turn turbine and use the free flow to dill tower?? Then i could create substantial Head an gpm yet to be determined?

  • bbop

    can you create hydro power in a pool using the pool pump as the source?

  • Matt Crume

    This is a great site outlineing some pros and cons of micro-hydro. If anyone has any questions feel free to visit my site,

    We have a free micro-hydro calculator, and can provide low head and high head systems for smaller sites.

  • iddi

    what is the formula for calculating the number of jets required for turbine?

  • FreeOurEarth

    Hi thanks for the info. We have a 12m pool situated about midway on property which has a few metres drop. would it be possible to generate some electricity by using the land gradient to obtain a flow of water from the pool toe drive a generator and a windmill to return the water to the pool. Thank you.

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