Microhydro Systems: Advice From The Pros: Page 5 of 6

Beginner
Microhydro Intake
The right intake design will affect system performance greatly.
Microhydro Intake Site
Asian Phoenix’s Power Pal Low-Head Turbine
Asian Phoenix’s Power Pal low-head turbine in Honduras. At lower heads than this, things get tricky.
Altimeter
An altimeter is used to survey elevation. This measurement shows only 180 feet of head, but with a 12-inch pipe, this site will develop 75 kW.
Don Harris
Hydro guru Don Harris.
Measuring Head with the Bucket Method
The “bucket method” can be used to measure flow in small streams. Larger streams require an alternative measurement method.
Measuring Head with a Pressure Gauge
95 psi shows the static head of almost 220 feet of head.
Hugh Piggott, Scoraig Wind Electric
Hugh Piggott, Scoraig Wind Electric
David Seymore, Asian Phoenix Resources
David Seymore, Asian Phoenix Resources
Denis Ledbetter, Lo Power Engineering
Denis Ledbetter, Lo Power Engineering
Christopher Freitas, WiFu Energy
Christopher Freitas, WiFu Energy
Joseph Hartvigsen, Hartvigsen-Hydro
Joseph Hartvigsen, Hartvigsen-Hydro
Scott Davis, Friends of Renewable Energy BC
Scott Davis, Friends of Renewable Energy BC
Excavator Placing Pipe
An excavator lifting a 3,000-pound section of 8-inch steel onto a steep slope. The pipe was then pulled 500 feet up the hill using the excavator and a long steel cable through a pulley.
Microhydro Intake
Microhydro Intake Site
Asian Phoenix’s Power Pal Low-Head Turbine
Altimeter
Don Harris
Measuring Head with the Bucket Method
Measuring Head with a Pressure Gauge
Hugh Piggott, Scoraig Wind Electric
David Seymore, Asian Phoenix Resources
Denis Ledbetter, Lo Power Engineering
Christopher Freitas, WiFu Energy
Joseph Hartvigsen, Hartvigsen-Hydro
Scott Davis, Friends of Renewable Energy BC
Excavator Placing Pipe

Q: What are common challenges encountered in installation?

Each site has its own challenges, but most are overcome by the use of common sense and some basic engineering skills. Steep, wooded terrain and rocky stream courses can make installation more difficult.

Specific challenges include:

  • Intake site selection and installation
  • Proper pipe selection and installation, including dealing with poor access and long distances
  • Routing pipeline or power line over rough or steep terrain
  • Avoiding private land, public land, or road crossings
  • Air blockage in pipes laid with an uphill slant
  • Proper transmission cable selection, installation, and protection
  • Inaccurate measurements of head, flow, and distances
  • Protection of penstock from sun, slides, and other physical damage
  • Permitting and regulatory issues
  • Freezing conditions (i.e., ice plugging screens and low water levels)

Another significant challenge in microhydro installation is finding local, experienced installers. Many more people install solar-electric systems and some also install wind-electric systems with some level of expertise, but microhydro is the most obscure of the renewable technologies.

Q: Have there been any notable advances in turbine, control, or system design strategies in recent years?

There have been only a few major advances. Some improvements have been made by tweaking original designs, such as adjustable guide vanes on certain low-head, propeller turbines and adjustable permanent-magnet alternators.

Modern electronic load controllers have freed us from the need for the elaborate and delicate mechanical speed-governing systems used in the past. Inexpensive permanent magnets now allow manufacturers to offer very efficient, simple battery-charging alternators. The use of induction motors as generators has reduced the cost of basic AC hydro systems.

Hydropower systems continue to become more efficient and reliable, but most hydro systems are based on fundamental principles that have been proven for more than 100 years. New on the scene is the ability to maximum power point track (MPPT) a hydro turbine, which can solve some of the mid-range transmission issues mostly for 12- or 24-volt systems. MPPT controllers allow a hydro turbine to run above battery voltage, allowing longer wire runs and more efficient output—both in the operation of the turbine and in the line losses. And rather than having to manually adjust some alternators’ magnetic field as battery voltage and flows fluctuate, a MPPT controller can do it electronically.

Grid-tied equipment is gradually moving into the microhydro world, increasing the opportunities to sell energy to local utilities. “Bleeding edge” technology has experimenters using PV arrays as part of hydro control strategies (using the array as a zener diode) in both battery-based and batteryless systems.

Comments (11)

CarlRising-Moore's picture

Thank you for this information Michael. Please tell me the name of the yahoo group,

Michael Welch's picture
It's just called microhydro. Go to Yahoo groups, and search for it.
CarlRising-Moore's picture

I am just learning about micro hydro. My family has recently purchased a 2 hector property on Negros Island, Philippines. The property has a spring that has been producing a flow of water that never stops. After reading this information, my next step is to measure the volume from the head, and measure the drop to where a system can be installed. I am limited to the drop, because the spring water drains into a major river approximately 30 feet below the spring. After I calculate the flow and drop, I will post the results here.
Do you know of any experts in microhydro here in the Philippines? I will try to learn as much as possible, however, I will need some expertise to put the system together, if in fact my calculations demonstrate the potential for a microhydro system. I plan to share my project with the School of Electrical Engineering here at the Central Philippines State University.
Thank you all for your efforts to promote and educate the public about the importance of switching to renewable energy. Our Secretary of the Environment, Gina Lopez is currently in Morocco where she is promoting the concept of all developing nations switching to 100% renewable energy by 2030.
Clearly, your resource here indicates that you are the pioneers in this effort to rid the world of our addiction to fossil fuels.

Michael Welch's picture
Hi Carl. There is a great Yahoo Group called microhydro. That would be a good place to find recommendations for experts near you.
ripsaw's picture

Ok, first time poster and have just a simple question.
I run my irrigation system for about 3 hours everyday for my lawn and flowers. Question is this, given my water pressure is 65PSI running through a main that tees off for my sprinkler system that is 1.5 inches do they make micro hydro generator for this type of application? Does it even make sense to even think about such a thing?

Michael Welch's picture
No. In fact, it may even be illegal to use your municipal water system to generate electrical energy. Think of it this way, for every little bit of energy you take out of the municipal water system, the system's pumps have to make up for it.
Cornè's picture

Hi is it possible to build an micro-hydro-energy storage system with an upper reservoir and a lower reservoir with a head of about 20 meter. If it is how can I calculate the flow rate and output power.
I'm a final year engineering student at the NWU in Potchefstroom South Africa, my final year's project is to give farmers a cheap emergency storage system for when they have a power outage. I have to design a small prototype.

Michael Welch's picture

Yes, it is possible but most likely not practical. For example, if you wanted to make 1,000 watts of power available for a full day, you would need more than 26,000 gallons in the upper reservoir.

The formula for very roughly approximating potential power is:

(flow in gpm × head in feet) ÷ 12 = power available

So, gpm = 12 x 1000 watts ÷ 66 ft. = 181 gpm

181 gpm x 60 minutes x 24 hours = about 26,000 gallons used in one day

Heetel64's picture

If you are lucky enough to have a water source, study it.
An example would be a water source with a bend. Consider putting two independent wheels, smaller one on the outside ( faster flow ) and larger one on the inside with reducer gearing ( slower flow ). Should you find that the water supply is reduced, then design your system to allow for moving the larger wheel into the outer bend.
Never think that your water source will never change.

Frank Heller's picture

For remote sites where the owner has access to enough water to generate 1+ KW; it may be advisable to install microhydro should the distance to the nearest power line be 2 or more poles away. In Maine, a pole typically costs about $9,000.

On the other hand going off the grid is not for the faint hearted.

Frank Heller's picture

Don't dismiss the water wheel so quickly. A large slowly turning water wheel can provide enough torque to power a transmission so that a 300:1 or greater increase in RPM can be obtained. A large wheel with a small amount of water may do the same. Depends on whether it is in the current or powered by the weight of falling water.

There are also large volumes of water impounded in tidal pounds that can power a modern equivalent of the Roman tub turbine. In Maine we have 11' tides and there is an infrastructure of tidal ponds which ran approx. 2,000 tidal water mills.

OREC and others now use variations of the Gorlov turbine in swift underwater ocean currents. Tidal barrages using compression waves can also drive large turbines, i.e. SEABELL of Tokyo.

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