Micro-Hydro Power System — FarmPal

The gold standard of off-grid power for properties with flowing water. A small stream with adequate head (vertical drop) can produce continuous 24/7 power, often eliminating the need for large battery banks.

How It Works

Water is diverted from a stream through a pipe (penstock) that drops in elevation. The falling water spins a turbine connected to a generator. Water returns to the stream below. Power output depends on flow rate and head (vertical drop).

Site Requirements

  • •Year-round water flow (measure minimum dry-season flow)
  • •Vertical drop (head): minimum 5-10 feet, ideally 50+ feet
  • •Water rights or permission to divert (check state laws)
  • •Route for penstock pipe from intake to turbine
  • •Stream must have sufficient flow even in dry months

Components

Intake/Diversion
Capture water from stream without blocking it
$200-1,000
Penstock Pipe
Carry water downhill to turbine under pressure
$2-10/foot
Turbine/Generator
Convert water energy to electricity
$1,000-5,000
Controller/Regulator
Maintain constant load and voltage
$200-800
Dump Load
Absorb excess power when batteries are full
$50-200
Transmission Wire
Carry power from turbine to house
$1-5/foot depending on gauge

Sizing Guide

Continuous power output depends on head and flow

Formula
Watts = Head (ft) × Flow (GPM) × 0.18 × Efficiency (typically 50-70%)
DIY Minimum
$1,500 (small Pelton wheel system)
DIY Typical
$3,000-8,000 (complete homestead system)
Professional
$10,000-30,000 installed
Annual Maint.
$100-300 (intake cleaning, bearing service)

DIY Steps

1
Stream Assessment

Measure flow rate (gallons per minute) and head (vertical drop from intake to turbine). Power = Head (feet) × Flow (GPM) ÷ 10. This gives approximate watts.

⏱ 1 day measuring, months of monitoring
2
Intake Construction

Build a small diversion weir or intake box in the stream with a trash rack (screen) to keep debris out. Only divert a portion of stream flow.

⏱ 2-4 days
3
Penstock Installation

Run pipe from intake to turbine location following the terrain. Pipe diameter must be large enough to minimize friction losses.

⏱ 1-5 days depending on distance
4
Turbine Installation

Install turbine at low point. Pelton wheels for high head/low flow, Turgo for medium, crossflow for low head/high flow. Connect to generator and electrical system.

⏱ 2-4 days

✓ Pros

  • •24/7 continuous power day and night, rain or shine
  • •Smallest battery bank needed of any renewable (often just a few hours backup)
  • •Most cost-effective renewable per kWh produced
  • •Extremely long lifespan (turbines last decades)
  • •Minimal environmental impact with run-of-river design

⚠️ Safety

  • •Working near flowing water carries drowning risk
  • •Pressurized penstock can burst use appropriate pressure ratings
  • •Spinning turbine is dangerous install guards
  • •Electrical work in wet environment requires GFCI and waterproof enclosures