RENEWABLE ENERGY SYSTEMS MODULE 2.pdf ppt

Module 2

1. RENEWABLE ENERGY
SYSTEMS
MODULE 2

2. ⚫The ocean is the world’s largest solar collector.
⚫Ocean thermal energy conversion (OTEC) generates
electricity indirectly from solar energy by harnessing
the temperature difference between the sun warmed
surface of tropical oceans and the colder deep waters.

3. Methods to harness Ocean Thermal Energy
1.Open cycle
2.Closed cycle
3.Hybrid cycle

8. CLOSED CYCLE (ANDERSON CYCLE)

13. ⚫The warm seawater is pumped to the evaporator
⚫The working fluid will absorb heat from the warm
water.
⚫Evaporated ammonia will run the turbine
⚫The ammonia in vapour form is condensed to liquid
form.
⚫ Cold water is pumped to the condenser to reduce
heat.
⚫This cold water can be returned to sea.

18. • It causes degradation to the primary purpose of
that item.

20. Criteria for site selection of OTEC
⚫Study area
⚫Net electric power
⚫Environmental factors
⚫Availability of water
⚫Temperature
⚫Salinity

21. TIDAL ENERGY
⚫Tidal energy is a form of hydro energy recurring with
every tide.
⚫ The periodic rise and fall of sea water level which are
carried out by the action of sun and moon on the
ocean water is called Tide.
⚫If some parts of this vast energy can be converted into
electrical energy, it would be an important source of
hydropower.

22. ⚫Tidal power is a form of hydropower that converts the
energy of tides into useful forms of power, mainly
electricity.
⚫It is one of the best available renewable energy
sources.

23. TIDAL POWER PLANTS
⚫Here, the energy of tides is converted into useful form
of power.
⚫Tidal power has more potential for future electrical
generation and is more predictable than wind and
solar energy.
⚫The main feature of tidal cycle is the difference in
water surface elevations at high tide and low tide.

24. ⚫If this differential head could be utilized in operating
a hydraulic turbine, then this tidal energy could be
converted into electrical energy by means of an
attached generator.
⚫The difference in potential energy during high tide
and low tide is converted into electrical energy.
⚫The power is obtained through the flow of water
when filling and emptying partially closed sea basins.

25. Components of Tidal Power Plants
⚫The tidal power plants involve the creation of huge
concrete dams with sluices. These are called barrages.
⚫Tidal barrages make use of potential energy due to
the difference in height between high and low tides.
⚫Most of the existing power plants use this type of
design. The main components of these power plants
are:
a) Dam
b) Sluice ways
c) Powerhouse

26. Dam or dyke –
The function of dam or dyke is to form a barrier
between the sea and the basin or between one basin
and the other in case of multiple basins.
It is built across the mouth of a tidal inlet. This
barrage is fitted with special sluice gates that are
opened and closed during different stages of the tide.

27. Sluice ways –
These are used to fill the basin during the high tide or
empty the basin during the low tide, as per
operational requirement.
These devices are controlled through gates, vertical
lift gates and flap gates are mainly used in existing
plants.

28. Powerhouse –
A powerhouse consists of turbines, electric
generators and other auxiliary equipment. Especially,
large sized turbines are used due to low head
availability.
The water with high potential energy is made to run
through the turbines to run generators for power
production.

29. Single Basin Tidal Power Plant

30. ⚫ In single basin arrangement, only one basin
interacts with the sea. The sea and basin are
separated by a dam or dyke. In a single basin, single
effect arrangement, power can be generated only
intermittently.
⚫ It is the simplest and most common form of
barrage power generation, which is called as ebb
generation. The basin is filled by keeping the sluices
open and letting the water flow from the sea to the
basin during high tide.
⚫ The turbine gates are kept closed until the sea level
is filled to create an enough head across the barrage.
Power is generated by letting the water flow from the
basin to the sea through turbines during low tide.

31. ⚫The stored water is made to flow through turbines to
sea when its gate is open to generate power until the
head is low. When the generation stops, the gates
protecting the turbines are closed again and the
sluices are opened so that the basin is again filled.
The cycle repeats itself.

32. DOUBLE BASIN TIDAL POWER
PLANT

33. ⚫The main drawback of single basin plant is that it is
dependent on tidal fluctuations. Due to this, the
power generation is not continuous. A double basin
plant can provide power continuously or on demand,
which is a great advantage.
⚫The figure shows a double basin tidal power plant. In
the simplest double-basin plant, a dam is built across
the mouth of a bay or an inland basin (Dam A).

34. ⚫This inland basin is further divided into a high basin
and low basin by another dam (Dam B).
⚫Water level of high basin is maintained always at a
higher level than the lower basin.
⚫The high basin is periodically filled from the ocean at
the times of high tides and the low basin gets
periodically emptied at low tide.

35. ⚫Power generating turbines are installed in dam B
through which water flows from high basin to the low
basin.
⚫Due to this, the fluctuations in the head are
minimized and the system is much less dependent on
tidal fluctuations.
⚫However, this system is very costly and complex.