07 OZE 2014 01 10 en

7 HYDRO POWER PLANTS

7.1 Water – as an energy source

Similarly as all other renewable sources, hydropower has its origin in the solar energy too.
The movement of surface water in streams is a part of the hydrological cycle in the nature.
Energy source of this moving is solar energy, therefore the energy of water flows is continually

renewed, and thus it is inexhaustible. Energy of rivers is about 0,4 % of energy delivered by the

Sun.
Energy utilization is possible using:

- the mechanical energy of rivers (major using)

- the mechanical energy of tides, sea waves (minor using)

http://oki.krakow.rzgw.gov.pl/Article.aspx?tid=tabEdukacja&
id=eduObieg
http://www.infometeo.republika.pl/woda.html

Obieg wody w przyrodzie

Scheme of balance of the hydrological cycle in

nature in [10

]

7.2 Hydropower potential

Each water flow represents certain amount of energy, which is determined amount of

overflow water and the difference heights on which the water flows.

Power [W] of a part of water flow (1-2) is given by:

- density of water [1000 kg.m

-3

]

- gravitational constant [9,81 m.s

-2

]

- flow rate of water [m

-1

]

- height difference between inlet and outlet [m]

Production of electricity in hydroelectric power is accompanied by losses incurred

in turbine, generator and transformer.

The power taken from the alternator is:

- efficiency of hydro-power plant

- efficiency of turbine (0,85÷0,95), generator (0,95÷0,99), transformer (0,92÷0,98)

7.3 Dividing of hydro power plants

a) according to solution of using of energy water flow

a1) river

– water supplied to the turbine does not leave the river bed, the plant is located

on the river.

a2) derivative

– water leaves the original the river bed and to the turbine it is fed either by

open channel or pipe.

Open channel

Pressure channel

b) according to the operational method and method of energy storage:

b1) run of the river hydro power plants

- this type doesn’t have the storage capacity. The water flows and passes through the

turbines, power depends on the instantaneous flow rate. This type of hydro power plant

operates mostly in the base of the daily load diagram.

b2) storage power plants with the natural accumulation of water

- these power plants have available reserves of water in the reservoir,
- water flows into the reservoir naturally.

Wybrane elementy charakterystyki

zbiornika zaporowego

http://levis.sggw.pl/~ozw1/zgw/msos/00_01/wodypow/podzialwod.htm

b3) storage power plants with artificial accumulation of water (pump storage power plants)

- these power plants artificially accumulate energy at the time of reduced load (or excess of

electricity) on the power system in the form of water by pumping of water from the lower

reservoir to the upper reservoir.

- hydropower resources in the upper reservoir are used to generate electricity during the peak of

daily load diagram (turbine operation).

Chladný, V.: Výroba elektriny, Košice, 2006

http://climatetechwiki.org/technology/jiqweb-ph

Pump storage power plant (Elektrownia szczytowo-

pompowa)

In terms of machine configuration, pump storage power plants are constructed as:

a) 4-machine configuration (1. turbine - 2. generator, 3. motor - 4. pump)

Chladný, V.: Výroba elektriny, Košice, 2006

b) 3-machine configuration (1. motor-generator, 2. turbine, 3. pump)

c) 2-machine configuration (1. motor-generator, 2. reverse turbine).

7.4 Water turbine

Pelton turbine

- water is supplied to the impeller wheel tangentially through one or more nozzles
- impeller wheel is always saved in the turbine housing, which prevents spattering water and

directs it to the discharge

- regulation of water flow in the nozzle is performed using the spear located in the nozzle axis.
- pelton turbine is usually used for high difference between inlet and outlet and smaller flow rate

of water.

http://www.oze.stuba.sk/oze/vodna-energia/

http://www.youtube.com/watch?v=WwNpls58cso

http://www.youtube.com/watch?v=BvSe7Frhb9E