What Is Hydro Power?
is a Greek word, which means water. Hydro electricity
is the conversion of the mechanical energy in flowing water
into electricity. Hydro electricity is generated when
the force of falling water from dams, rivers or waterfalls
is used to turn turbines, which then drives generators
that produce electricity. The energy produced is directed
to a substation, where transformers "step up" the
voltage before its transmission to the electricity grid.
The amount of power that can be generated by a hydro
station depends on the height from which the waterfalls
(called the head) and the amount of water available (the
flow). The greater the head and the flow, the more electricity
can be produced.
Technology Of Generating Hydro Energy
Hydropower plants capture the kinetic energy of
falling water to generate electricity. A turbine and a
generator convert the energy from the water to
mechanical and then electrical energy. The turbines
and generators are installed either in or adjacent to
dams, or use pipelines (penstocks) to carry the
pressured water below the dam or diversion structure
to the powerhouse. Hydropower projects are generally
operated in a run-of-river, peaking, or storage mode.
Run-of-river projects use the natural flow of the
river and produce relatively little change in the
stream channel and stream flow.
A peaking project impounds and releases water when the
energy is needed. A storage project extensively
impounds and stores water during high-flow periods to
augment the water available during low-flow periods,
allowing the flow releases and power production to be more
constant. Many projects combine the modes. The power
capacity of a hydropower plant is primarily the function
of two variables:
(1) flow rate expressed in cubic feet per second (ft3/s), and
(2) the hydraulic head, which is the elevation difference the
water falls in passing through the plant. Project design may
concentrate on either of these variables or both.
Application Of Hydro Energy
Hydro power accounts
for some 24% of the world's electricity, around 675,000MW.
In all, there are more than 300 large scale hydro power
generators worldwide. Canada, Brazil and New Zealand
have the highest proportions of hydro electricity generation.
While hydro electricity provides great potential for
electricity generation, there are environmental constraints
on the development of new hydro stations. Creating new
dams to facilitate the construction of these plants would
involve the inundation of ecosystems, and the generation
of greenhouse gases through anaerobic decay of vegetation
trapped under water. Increased interest has therefore
been generated by alternate hydro systems, such as "run
of river" schemes, which use the flow of a river
to turn turbines, or the use of existing dams to house
new hydro plants.