Microhydro Turbine Buyer’s Guide

Intermediate

Inside this Article

The late Chris Mason with his Nautilus propeller turbine producing 2.6 kW from 18 feet of head at Ironmacannie Mill in Scotland.
A successful hydro system is a unification of elements. The intake, a site-specific component, can be as simple as a screened pipe or a complex engineering and construction endeavor.
Power-conditioning and control equipment, especially load management (such as a diversion heating element), are key components to getting your turbine to work best for safety and energy needs.
The array of microhydro turbine types.
This PowerPal turbine by Asian Phoenix Resources is a propeller turbine running on only a few feet of head.
This Alternative Power & Machine turbine at Pholia Farm Creamery in Oregon utilizes a Pelton runner and a permanent-magnet alternator.
Three Energy Systems & Design Turgo Stream Engines offer redundancy and adjustability for seasonally changing flow rates.
A two-nozzle PowerSpout Pelton turbine by EcoInnovation installed by Harvey Mudd College students.
A four-nozzle Hydro Induction Power Turgo turbine sits in a modified plastic barrel and uses an induction generator.
This Scott Hydroelectric unit uses a crossflow runner and produces 1,000 W from 28 feet of head.
A Platypus Power turbine with Turgo runner and induction generator produces 7 kW from 240 feet of head.
A Lo-Power Engineering Harris Hydro four-nozzle Pelton turbine with a permanent-magnet alternator, ready for installation.
This four-nozzle Hartvigsen Hydro Turgo turbine has an induction generator driven by 56 feet of head for 4 kW output.
A large, single-nozzle Pelton turbine by Canyon Hydro produces 8 kW from 215 net feet of head.
A Dependable Turbines Pelton turbine with a brushless AC generator delivers 8 kW from 250 feet of head.

If you have a site for a microhydro system, it can be the best value of all the renewable sources you might use to power your home. As long as the water flows, your turbine will provide electricity. That means that a 1 kW hydro turbine can produce as much daily energy as a 5 kW solar-electric array, and with less reliance on batteries.

Hydro and solar electricity can work well together since the best solar season is often when streams are at their lowest flow. Off-grid hybrid systems help to keep the engine generator silent, come rain or shine.

What is a Microhydro System?

There are many parts to the whole system that you will need. The turbine is not likely to be the most expensive, although you should choose it with care. You will need:

  • Intake/diversion to collect the water
  • Penstock—the pipe that carries the water
  • Manifold, to distribute the water to turbine nozzles
  • Turbine with generator
  • Tailrace, to return the water to its course
  • Transmission wiring
  • Electrical balance of system (BOS) gear

Since the electrical energy produced is often more than is consumed by a home, consider what’s to be done with the excess. If the system is grid-tied, this energy can be put on the grid and, often, credited to your utility bill through “net metering.” For off-grid systems (or in places without net-metering or other utility payment programs), heating water or even heating your house in winter are good uses for the extra energy. This can be done using normal AC heaters and controlled by “auxiliary relays” in charge controllers or inverters, or by independent control devices.

System Planning

Siting your intake and turbine is the first step. Look for the best flow of water falling the most height over the shortest penstock length, and not too far from your home. Learn to measure the head and flow accurately (see “Methods: Hydro Measurements” in HP170). Then see the table (or equations) below to estimate energy production. Compare this to your current usage and future needs. Take into account that stream flow varies over the year. Most turbines can be adjusted to use less flow and still produce useful energy.

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