This document outlines osmotic power, which generates energy from the difference in salt concentration between seawater and freshwater. It works via pressure retarded osmosis (PRO) where freshwater naturally moves through a semi-permeable membrane into higher salinity seawater, increasing pressure. This pressure powers a turbine to generate electricity. Key components include membrane modules to separate the waters, filters to optimize membrane performance, and a turbine/generator. Experimental results showed a prototype achieving over 90% efficiency and the potential to scale installations by adding more membrane modules.

1. OSMOTIC POWER
Submitted By,
Snehitha Bolla(2619442)
Raja Sandeep (2660330)

2. OUTLINE
 Motivation
 Introduction
 Osmosis
 Osmotic power
 Principle
 Pressure retarded
osmosis (PRO)
 Construction
 Components
 Operation
 Experimental results
 Advantages
 Disadvantages
 Future scope
 Conclusion

3. MOTIVATION
 Non conventional power in
various sources is effected
predominantly by climatic
conditions and cannot be
operated throughout the
year.
 Need for development of
new type of non
conventional power that can
be operated 24/7 and that is
osmotic power.
 First osmotic power plant is
built in Tofte, Norway in
2009.

4. INTRODUCTION
 Osmotic power is energy available from difference
in salt concentration between sea water and river
water.
 It is huge and unique energy source.
 Renewable energy source that converts pressure
differential between water with high salinity and
water with lower or no salinity in to hydraulic
pressure.
 Fresh water moves by osmosis through membrane
in to sea water.

5. OSMOSIS
 Physical process in
which solvent moves
across semi permeable
membrane separating
solutions of different
concentrations.
 Osmosis is vital
process in biological
systems as biological
membranes are semi
permeable.
Before Osmosis After Osmosis

6.  Osmotic pressure:
 Minimum pressure that should be applied to a
solution to prevent inward flow of water across semi
permeable membrane.
 Measure of tendency of solution to take in water by
osmosis.
 Potential osmotic pressure:
 Maximum osmotic pressure that can be developed
in a solution if it were separated from fresh water by
a selective permeable membrane.

7. OSMOTIC POWER
RESULTS
Conclusion

8. PRINCIPLE
 Osmotic power is
generated by pressure
retarded osmosis
(PRO).
 Technique to separate
solvent (fresh water)
from a solution that is
more concentrated
(sea water) and also
pressurized.
Turbine

9. PRESSURE RETARDED OSMOSIS
 It relies on water molecules moving through a semi
permeable membrane.
 Semi permeable membrane allows solvent (fresh
water) to pass to the concentrated solution (sea
water) side by osmosis.
 This technique can be used to generate power from
salinity gradient energy resulting from the difference
in salt concentration between sea water and river
water.
 Output is proportional to the salinity.

10. CONSTRUCTION
Fig: Commercial Setup for Osmotic Power Generation

11. COMPONENTS
1. A semi permeable membrane contained in
modules.
2. Fresh water and sea water filters that optimize
membrane performance.
3. A turbine that generates a driving force based on
osmotic pressure and permeation flow rate.
4. A pressure exchanger that pressurizes sea water
feed required to maintain high salinity levels
downstream from membrane.

12. OPERATION
Fig: Operation of Osmotic power

13. OPERATION
 Fresh water and sea water sent into two different
modules.
 The two modules are separated by a semi-
permeable membrane.
 The Fresh water seeps through the semi-
permeable membrane to the Salt water side.
 This increases pressure on the salt water module.

14. OPERATION
 The salt water flows
through the turbine which
in turn generates
electricity.
 The brackish water is sent
out to the sea.
 The high pressure salt
water is again sent to the
modules through a
pressure exchanger.Fig:Francis Turbine
(Cortesy: www.Google.com)

15. EXPERIMENTAL RESULTS
Fig: Plot to describe salt water pressure
for the flow of water

16. EXPERIMENTAL RESULTS
Fig. Power production from prototype membranes
TFC: Thin film membrane composite;
CA: Asymmetric Cellulose Acetate

17. EXPERIMENTAL RESULTS
Fig: Results for maximum power density (Wmax)

18. EFFICIENCY
 The efficiency of this Osmotic power is 91.0%.
 The Efficiency(Npx) of the Osmotic power is given by
the above expression.
 Emech,salt is the energy potential of salt water.
 Emech,brackish is the energy potential of fresh water.

19. ADVANTAGES
 Steady, predictable output.
 Adaptable for small or large generating stations.
 Scalable or modular design (membrane modules
added as required), making it possible to increase
installed capacity.
 Generating sites near load centers, limiting power
transmission needs.
 Good potential for power plant sites.

20. ADVANTAGES & DISADVANTAGES
 Technology similar and complementary to that of
hydro-electric power, with osmotic power plants
able to be built on already-harnessed rivers.
 High risk of clogging and gradual degradation of
semi-permeable membranes, necessitating
pressure-filtering pretreatment of fresh water and
periodic membrane re-placement (every 5 to 7
years)

21. CONCLUSION
 An analysis of the PRO processes for energy
production from mixing of freshwater and seawater
has been performed at realistic conditions for
physical plant operation.
 A freshwater utilization efficiency of 40% of the
maximum mixing energy of freshwater with sea
water.

22. THANK YOU