How to Start Your Own Small-Scale Hydroelectric Power Plant

How to Start Your Own Small-Scale Hydroelectric Power Plant

How to Start Your Own Small-Scale Hydroelectric Power Plant


Starting a small-scale hydroelectric power plant can provide clean, renewable energy and even generate income. However, it requires careful planning and adherence to regulations. This guide will walk through the key steps I took to successfully build my own small-scale hydroelectric plant.

Selecting a Site

The first step is identifying a suitable site. Ideal locations have a flowing body of water with a height drop, known as “head.” Some main factors to consider when selecting a site:

  • Water flow rate – Aim for at least 5 cubic feet per second (cfs). This provides sufficient flow for power generation.

  • Head height – The vertical drop in the water level. Aim for at least 2 feet of head. More head equals more power potential.

  • Water rights – You’ll need legal rights to use the water flow for hydroelectric generation. Research water rights in your area.

  • Accessibility – The site needs to be accessible for construction and maintenance. Remote locations add costs.

  • Permitting – Opt for sites that simplify permitting. Some areas prohibit hydroelectric dams.

After surveying a few local streams, I settled on a site with 7 cfs flow and 6 feet of head. It was on my own private property, avoiding water rights issues.

Determining Power Potential

The next step is to calculate the site’s power potential. This helps size the system components. The key formula is:

Power (Watts) = Head (feet) x Flow (cfs) x efficiency coefficient

For my site with 6 feet of head and 7 cfs flow, assuming a 70% efficiency coefficient, the power potential was:

6 x 7 x 0.7 = 29.4 kW

With about 30 kW potential, I could install a 20 kW hydroelectric system comfortably.

Selecting Turbine Type

There are two main types of hydroelectric turbines:

  • Impulse – Uses the water velocity to turn. Needs high head (30+ feet typically).

  • Reaction – Uses the water pressure. Ideal for low head sites.

Since my site had just 6 feet of head, I opted for a reaction turbine. Reaction turbines are compact and work efficiently in low head areas. The two main sub-types are Francis and Kaplan turbines. I went with a Francis turbine due to its simple design and maintenance.

Sizing Other System Components

With a 20 kW Francis turbine selected, I sized the other components accordingly:

  • Intake – A 30-inch wide diversion to channel water to the turbine.

  • Headrace – A 300-foot long, 36-inch diameter above-ground PVC pipe feeding water from the intake to the turbine.

  • Generator – A 22 kW generator matched to the turbine output.

  • Dump load – A resistor bank to dissipate excess power when demand is low.

  • Powerhouse – A simple 20x12ft shed housing the turbine and generator.

Obtaining Permits

Building a hydroelectric system requires multiple permits. Key permits I had to obtain:

  • FERC exemption – Projects under 5 MW can be exempt from FERC licensing. I qualified for this.

  • Building permit – Needed for the powerhouse and structures.

  • Environmental approval – Ensures minimal impact on local wildlife.

Understanding the permitting process and timelines is critical. I allotted 6 months to get all my permits before starting construction.

Handling Project Finances

With permits in place, I handled project costs:

  • Turbine/generator/components – $42,000
  • Construction materials – $12,000
  • Labor – $15,000
  • Total – $69,000

I was eligible for a 30% state rebate since this was a small, low-impact hydro system. This reduced my net costs to around $48,000.

I estimated the system would generate about 140,000 kWh annually. At a retail electricity rate of $0.11/kWh, the value of this generation was about $15,000/year. With no fuel costs, the project payback period was just over 3 years.


The construction process took about 5 months:

  • Intake/headrace – I dug trenches to bury the majority of the headrace pipe. The intake box was installed in the stream.

  • Powerhouse – The pre-built shed was delivered and installed on a gravel foundation near the headrace endpoint.

  • Turbine/generator – The Francis turbine and generator were anchored to concrete pads inside the powerhouse.

  • Controls – The control panel, inverter, and monitoring system were wired and configured.

  • Testing – After construction I thoroughly tested the system and monitored for any issues.

Operating and Maintaining the System

With everything functioning properly, the system was ready for continuous operation. Key maintenance items include:

  • Monitoring power output and inspecting for damage.
  • Checking water flows and removing debris from the intake.
  • Testing the generator, controls, and dump load.
  • Greasing turbine bearing per the manufacturer instructions.


Building a small hydroelectric plant was very fulfilling, and provides my home with clean, renewable power. The process requires diligent planning and preparation, but it’s feasible for an individual with sufficient time and resources. The regulatory environment also favors small systems, provided you do your homework. If you have access to a suitable hydro resource, I encourage you to explore harnessing it to generate your own renewable power.