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Hydro

HYDRO: Water is Power

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(You are at Part 6 of The Energy Chain, if you would like to start at the beginning part, click here.)

A basic question about Hydro:

What exactly is Hydro Power? Water can't exactly be "burned" in an engine, so how is it an energy source?

Water is technically NOT an energy "source". It cannot be burned directly or be converted into "work" simply by standing there (but see our Hydrogen section for how it CAN be "burned" indirectly!).

In Hydro Power, water is actually a STORAGE medium.
That's right...think of a hydro dam as a really, really big battery.

With Hydro Power, WATER ENERGY is stored as WATER PRESSURE.
When needed, it can then be CONVERTED into ELECTRICAL ENERGY via a WATER TURBINE or turned into MECHANICAL ENERGY via a water wheel and gears.

The technical terms for measuring WATER ENERGY in Hydro Power are:

HEAD HEIGHT: This is the vertical measurement (or depth) of the water from the bottom of the dam to the top surface of the water.
FLOW: This is the rate (or volume) at which the water in a dam can flow out.

Lake Kops, Vorarlberg, Austria
(picture compliments of VA TECH HYDRO: www.vatech-hydro.com)

The taller the dam, the greater the HEAD HEIGHT. How much water is in the dam will determine the FLOW at which the water can be used. Together HEAD HEIGHT and FLOW create a tremendous amount of WATER PRESSURE.

It is this water pressure that can then be used to "physically" turn the blades or buckets of a WATER TURBINE. A water turbine converts WATER PRESSURE into ELECTRICAL ENERGY by turning the blades or buckets of the turbine (MECHANICAL ENERGY).

The movement of the water turbine turns an ELECTRICAL GENERATOR, which generates electricity that can be used for all type of things...like powering your house, for example.

Types of Water Turbines

AXIAL-FLOW Turbine:
These look a bit like a boat propeller.

(picture compliments of VA TECH HYDRO: www.vatech-hydro.com)