A Guide to Hydropower

This document tries to explain all of the essential issues you should know about if considering developing a micro hydropower or small hydropower system. Just a quick mention of terminology; micro hydro refers to hydropower systems up to 100 kW power output, and small hydro to systems up to 10 MW output.

Micro and small hydropower builds run-of-river hydropower systems, not storage hydropower systems. The key difference is that run-of-river hydro uses the water that is available in the watercourse at any instant rather than storing it behind a dam for use later. Run-of-river hydro has no way of storing water, so it makes use of hydro turbines that can operate on wide flow ranges so that they can efficiently generate energy on high or low flows, whatever is in the watercourse at the time.

The rest of this page describes in detail all of the factors you need to consider if you are thinking of developing a small hydropower or micro hydropower site. It starts with the fundamentals of head and flow, then describes how the flow characteristics of a site determine the best type of hydropower system, and then how much energy and revenue a small hydropower or micro hydropower site could generate and what it would cost.


What is head? ————————————————————————-—-—-—-—-————— 1

What is flow? ———————————————————————————-—-—-—-—-———- 2

What is the minimum head and flow rate required? ————————–—-—-—-—-———– 4

How does micro hydro and small hydropower work? —————————-—-—-————– 5

How much hydropower could I generate? ——————————————–—-—-—-———– 6

How large should a hydro turbine be? —————————————————-—-—-—-——– 7

How much energy would a micro hydro or small hydro system generate? —————— 9

How much money could I earn? —————————————————–—-—-—-————– 10

How much do micro hydro and small hydro systems cost? —————–—-—————— 13

What would be the return-on-investment on a micro hydro or small hydro system? —— 14

What is the physical size of a hydropower system? ————————————-—-—-——- 15

What permissions do I need to build one?———————————————–—-—-——– 15

How long do they last? ———————————————————————-—-—-—-——- 16

I want to move ahead, what’s the next step?——————————–—-—-——————— 16

Read more from the below PDF link: 

Introduction to micro and small hydropower


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