Hydroelectric Power Calculator
(Based on avg 1.25 kW household consumption)
How Does Water Create Electricity?
Hydroelectric power is essentially the conversion of Gravitational Potential Energy into electrical energy. Water held high up (in a reservoir or river) has stored energy. When it falls, that energy turns into kinetic motion, which spins a turbine.
The amount of power you can generate depends on two critical factors:
- Head (Height): The vertical distance the water falls. High head = High pressure.
- Flow (Volume): The amount of water moving per second. High flow = High force.
The Physics Formula
To calculate the theoretical power output in Watts, engineers use this formula:
- P: Power Output (Watts).
- ρ (Rho): Density of water ($1000 \text{ kg/m}^3$).
- g: Gravity ($9.81 \text{ m/s}^2$).
- Q: Flow Rate ($m^3/s$).
- h: Head Height ($m$).
- η (Eta): Efficiency (Usually 0.80 to 0.90 for modern turbines).
Head vs. Flow: The Trade-Off
You can generate the same amount of power with different river types.
Scenario B (High Flow): A wide, slow river with only a 2-meter drop needs a huge volume of water to generate the same power. This requires massive "Kaplan" turbines (like the Hoover Dam).
What is Micro-Hydro?
You don't need a Hoover Dam to generate power. Micro-Hydro systems are small setups used by off-grid homeowners living near streams.
A simple system generating 1 kilowatt (1,000 Watts) continuously can power an entire energy-efficient home because unlike solar (which only works during the day), hydro runs 24/7.
Power Output Reference
| System Size | Output (kW) | Can Power... |
|---|---|---|
| Pico Hydro | < 5 kW | A cabin, lights, fridge. |
| Micro Hydro | 5 - 100 kW | A large house or small farm. |
| Mini Hydro | 100 kW - 1 MW | A small village or factory. |
| Large Hydro | > 100 MW | Cities (Grid power). |
Efficiency Losses
No system is 100% efficient. Energy is lost at multiple stages:
- Friction: Water rubbing against the pipe (Penstock) loses head pressure.
- Turbine: Mechanical losses as the water hits the blades.
- Generator: Electrical losses (heat) in the copper windings.
This is why our calculator includes an "Efficiency" field. A well-built home system might be 70% efficient, while a professional utility plant might be 90% efficient.