The need for renewable energy sources has never been bigger than today. To meet the current global energy requirement and to take into consideration the environmental aspects, a new renewable energy sources must be explored and improved. A relative unknown, renewable energy source is osmotic energy. It has been known for a long time that mixing two solutions with different salinities releases energy. The process of PRO pressure retarded osmosis is used to capture this energy.

1. By: Haneen Saymeh
A LITTLE-KNOWN RENEWABLE
ENERGY SOURCE

2. Whenever we consider the
renewable forms of energy,
we mostly consider the energy
produced from
the Solar and wind…etc

3. The energy released through the
mixing of fresh water and salt water
can be more easily explained using
the osmosis effect, hence the name
‘osmotic energy’.
When two solutions of different
concentrations (different salinities)
are separated by a membrane ,
water flows from less concentrated
solution to more concentrated
solution/equalize.

4. The concept of harvesting the energy generated
from mixing Waters of different salinities was first
reported by Pattle.
Re-investigated in the mid 1970s, Leob was the
first to report that osmotic energy could indeed be
harnessed energy
Slowed down again in the 80s
and 90s due to the expensive prices of the available
membranes
Experimental investigations on PRO were resumed
in the late 2000s by with recent advances in
membrane technology

6. In PRO, the feed(less concentrated)solution
flows towards the draw solution side because of
the positive osmotic pressure differential, for as
long as this difference remains greater than the
hydrostatic pressure difference (ΔP).
For steady power production, the salty water
side has to be maintained at constant pressure
and concentration while the feed
solution provides a constant flow through the
membrane.

7. The first PRO plant
In2009,the first osmotic
power plant prototype based
on the PRO technology was
finally opened
inTofte,Norway.
Statkraft announced the
termination of the PRO pilot
project at the end of 2012

8. PRO-Schematic of Statkraft’s PRO pilot
plant

9. RO-PRO hybrid plant-Fukuoka (Japan)

10. Membrane development
• High water permeability
• Low salt permeability
• Low resistance in the
support layer of the
membrane.
• Low affinity to fouling
substances
Efficiency of the membrane=
Required power/Area of the
membrane
Efficiency of the membrane:
efficiency varying from 1 to 5
W/m2

11. Plant design
Sea level PRO plant
Sub sea level PRO plant

12. Brackish water discharged near the
river mouth,
1- Release nutrients at the surface
layer, lead to local
eutrophication.(phosphates)
2-Temperature changes in the
surface Water (changes in the local
aquatic ecosystems)
3-Potential effects from chemical
cleaning of the membranes
Environmental impacts of osmotic power

13. Renewable
Green
Minimum ecological
foot print Off-shelf
technology
naturally occurring
equilibrium

14. 1-Osmotic power stands out as a promising and yet unexploited new,
renewable energy sources
2-In many countries from lab-scale to pilot-scale and is proven to be
feasible. Nonetheless, commercial-scale PRO or PRO-hybrid plants have
not been operated yet.
3-PRO technology are its ability to generate a constant and reliable
supply of power compared to other renewable sources like wind
and solar, and its low environmental impacts.
Conclusion

15. 1. E. ANDRADE1, J. H. (2016). OSMOTIC ENERGY, A LITTLE-KNOWN RENEWABLE
ENERGY SOURCE.
2. FernandaHelfer a, n. C. (2013).
OsmoticpowerwithPressureRetardedOsmosis:Theory,performance.
3. Jihye Kim 1, K. J. (2015). Recent Advances in Osmotic Energy Generation via.
4. Øystein S. Skråmestø*, S. E. (n.d.). Power Production based on Osmotic Pressure.
5. Stein Erik Skilhagen*, J. E. (2007). Osmotic power — power production based on the
osmotic.
6. Skilhagen, S.E.; Dugstad, J.E.; Aaberg, R.J. Osmotic power—power production based on the
osmotic pressure difference between waters with varying salt gradients. Desalination.
7. Saito, K.; Irie, M.; Zaitsu, S.; Sakai, H.; Hayashi, H.; Tanioka, A. Power generation with
salinity gradient by pressure retarded osmosis using concentrated brine from swro system
and treated sewage as pure water.
References

16. Thank you for listening