How to Build Your Own Off-Grid Hydroelectric Generator

How to Build Your Own Off-Grid Hydroelectric Generator

Going off the grid with renewable energy is becoming more popular as electricity prices rise and environmental concerns grow. Building your own off-grid hydroelectric generator allows you to generate clean, renewable electricity from flowing water on your property. With some mechanical know-how and the right materials, you can build a DIY hydroelectric system to power your off-grid home.

What is a Hydroelectric Generator?

A hydroelectric generator converts the energy of flowing water into electricity. The flowing water spins a turbine, which spins a shaft connected to a generator to produce electricity.

Hydroelectric generators use the potential energy of water flowing from an uphill source to a lower point to generate power. The farther the water falls and the more water moves through the system, the more electricity can be generated.

How a Hydroelectric System Works

Here are the basic components of a small-scale hydroelectric generator system:

  • Intake – The intake diverts water from the stream into a conveyance system. This is often an intake box with a debris filter and sluice gate to control water flow.

  • Conveyance system – This carries water from the intake to the turbine. It can be an open channel, PVC pipe or penstock.

  • Turbine – The turbine converts the water’s energy into rotational energy. Common turbines for DIY hydro systems include Pelton wheels, Turgo turbines and crossflow turbines.

  • Generator – The turbine shaft spins the generator to produce AC electricity. Common generators include permanent magnet alternators and induction generators.

  • Inverter – An inverter converts the generator’s AC power into usable 120/240V AC electricity for your off-grid home.

  • Dump load – A dump load dissipates excess electricity that isn’t needed. This keeps the system running smoothly.

  • Batteries – Batteries store energy for use when the hydro system isn’t generating enough electricity. Deep cycle batteries work best.

Choosing a Hydro Turbine

The type of hydro turbine you select depends on the water source and desired electricity output. Here are some common options:

  • Pelton wheel – Pelton wheels are impulse turbines suitable for high heads (over 30 meters) and low flow rates. They have good efficiency and can generate more electricity per liter/second of water than other turbines.

  • Turgo turbine – Turgo turbines are modified Pelton wheels that work for heads between 15-300 meters. They have high power output for their size.

  • Crossflow turbine – Crossflow or Ossberger turbines work for low heads down to 2 meters. They can handle high flow rates and debris well.

  • Archimedes screw – Archimedes screw turbines generate electricity from low head applications under 5 meters. They are inexpensive but less efficient than other options.

Consider the head height and water flow rate available when choosing a DIY hydro turbine. The power output will increase with more water flow and greater head height.

Sizing Your Hydroelectric System

To produce enough electricity for your needs, you need to properly size your hydroelectric generator system. Here are the key factors to consider:

  • Available head height – The vertical distance the water falls from intake to turbine. More head equals more power.

  • Water flow rate – Measured in liters/second or gallons/minute. More water flow yields more electricity.

  • Turbine efficiency – Each turbine type has different efficiency ratings based on flow and head height.

  • Desired power output – Determine how much electricity you need for your loads and size accordingly.

  • Generator capacity – Match your generator to the expected turbine power output.

Use online sizing calculators to input your site specifics and determine the right turbine size and power output. Oversize your system to allow for flexibility.

Construction Steps for DIY Hydro

Building your own hydroelectric generator is an involved but rewarding project. Here are the basic construction steps:

1. Evaluate your water source

  • Measure head height and flow rate over time to size your system properly.

  • Consider seasonal variations that may affect water flow.

2. Design and plan your system

  • Pick turbine type, generator, conveyance method, controls, etc.

  • Create diagrams and plans for your system. Obtain required permits.

3. Build water conveyance system

  • Install intake box, filter, sluice gate to divert water.

  • Build open channel, PVC penstock or other conveyance.

4. Install turbine and generator

  • Anchor turbine securely and ensure proper alignment with generator.

  • Connect generator and install dump load.

5. Build powerhouse

  • Construct a protective structure to house the generator and electrical components.

6. Install controls and route power

  • Install inverter, batteries, monitor system.

  • Safely route power to house with buried cables.

7. Test system and troubleshoot

  • Gradually start water flow and test generator power output.

  • Make adjustments to optimize performance.

Take safety precautions when working in or near water. Also check local regulations regarding diversion of water sources.

Maintaining a DIY Hydro System

Proper maintenance is crucial for consistent energy production and longevity of your hydroelectric system. Follow these upkeep guidelines:

  • Inspect intake and remove debris frequently to prevent clogging.

  • Check conveyance pipes and channels for leaks. Repair erosion or other damage.

  • Lubricate turbine and generator bearings annually.

  • Inspect electrical systems and tighten connections as needed.

  • Monitor battery voltages and water levels (for wet cell batteries).

  • Test and inspect dump load. Repair or replace if faulty.

  • Tune up generator by cleaning, adjusting brushes and rotor air gap as required.

Make regular maintenance part of your routine and your DIY hydro system will provide off-grid power for years to come.


Generating your own hydroelectricity from a DIY system is totally doable for the DIY enthusiast or acreage owner with sufficient water flow. Follow proper design, sizing and construction methods and you can build a small off-grid hydro system to produce clean energy for your homestead. Don’t forget to factor in regular maintenance to keep your system working efficiently for many years.