Get Started with Microhydro Power

Beginner
Turgo runner in an Australian-made Platypus turbine.
Shown from beneath—the 4-inch (10 cm) turgo runner in an Australian-made Platypus turbine.
A two-foot diameter Pelton wheel.
A view into a turbine shows a relatively large (2 feet in diameter) Pelton wheel. Peltons vary in size from 3 inches to 13 feet or more, depending on head and flow.
A Power Pal turbine with a Francis runner.
A Power Pal turbine with a Francis runner direct-coupled to the alternator above.
Nautilus turbine showing the Francis runner.
The underside of a low-head, high-flow Nautilus turbine showing the Francis runner, and above it, the innovative nautilus-shaped headrace.
The container fill method of measuring flow.
The container fill method of measuring flow means getting in the stream and timing how long it takes to fill a container of known volume.
Microhydro intake.
Intakes can be as simple as a screened box submerged in the watercourse, or they can involve a complete damming of the stream.
Turgo runner in an Australian-made Platypus turbine.
A two-foot diameter Pelton wheel.
A Power Pal turbine with a Francis runner.
Nautilus turbine showing the Francis runner.
The container fill method of measuring flow.
Microhydro intake.

Get Started with Microhydro Power

After you’ve done your load analysis and know how many kilowatt-hours you want to generate, a microhydro system site survey primarily focuses on four measurements:

  • The flow—how many gallons per minute (or in larger systems, cubic feet per second) are available, and how much water you want to divert from the stream;
  • The head, or vertical drop, between where the water is removed from the stream and where it leaves the turbine runner. Exactly where or how the pipeline runs is not vital for this measurement, though calculations of losses for pipe and fitting friction will need to be made;
  • The pipeline length, which, combined with its diameter, will allow you to price what may be one of the most expensive parts of the system;
  • The length of the transmission wiring, which may also be a significant cost, and must be sized to minimize energy losses, and be well within safety parameters.

For most people, a combination of motives—environmental, independence, reliability, and cost—make hydro-electric systems attractive. The “bottom line” may end up being what the actual cost per kWh is. To arrive at this, you’ll need a complete design along with construction bids or estimates. If it’s a grid-connected system you’re after, you’ll also need to know what your local utility policies are for renewable energy systems, and at what amount you will be credited or paid. You’ll also need to know if any incentives (utility or government) exist. Often, microhydro system incentives are less than those for solar energy systems, and sometimes non-existent. Available incentives, though, may be generous because of hydro’s 24-hour generation capability. Once you have these figures, you’ll need to predict how many years your system will operate and the annual maintenance costs, and then you’ll be able to calculate the cost per kWh.

Throughout your design, consider strategies to get the most out of your precious flowing water resource. Properly sizing the pipe will get the most energy to your turbine, minimizing friction loss. Choosing the right turbine and runner for the job will maximize production for your stream’s specific head and flow. And sizing the wire correctly will keep the system safe, and keep you from losing energy in the transmission of your hydro-electricity.

Get an education about common hydro myths, and avoid scams or schemes that promise more than they deliver. Lean on professionals and others with experience in the field to discover what has worked well to produce hydro-electricity. If you do your homework, and apply what you learn with care, hydro-electricity can provide low-cost, clean energy for many years.

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