SOLAR SEAWATER DESALINATION
Dr.–Ing. Joachim Koschikowski
Fraunhofer-Institute for Solare
Energy Systems ISE
© Fraunhofer ISE
Outline
 Development of the global
desalination market
 Overview on desalination
technologies
 Decentralized versus centralized
water supply systems
 Fraunhofer ISE activities on solar
desalination
© Fraunhofer ISE
The shortage of clean and safe water is one of the
most critical problems to be solved
Water has no alternative !!!
© Fraunhofer ISE
The shortage of clean and safe water is one of the
most critical problems to be solved
Water has no alternative !!!
Water
Energy
© Fraunhofer ISE
Food /
Industry
Development of the global desalination market
Desalination for industrial and domestic fresh water
supply is of increasing importance!
100
Global Capacity :
90
88 Mio m³/day
80
Multi Effect Dist. 7%
70
60
50
40
Reverse Osmosis 66%
30
20
10
Global desalination capacity
© Fraunhofer ISE
2014
2012
2010
2008
2006
2004
2002
2000
1998
1996
1994
1992
1990
1988
1986
1984
1982
1980
1978
1976
1974
1972
1970
1968
1966
0
1964
13.000 small and
medium scale
systems with an
average capacity of
1500m³ (25% of total
production)
Multi Stage Flash 21%
Mio m³/day
Membrane based
technology has
increasing share
Development of the global desalination market
Desalination for industrial and domestic fresh water
supply is of increasing importance!
Global Capacity :
88 Mio m³/day
Two major trends can be observed
Membrane based
technology has
increasing share
13.000 small and
medium scale
systems with an
average capacity of
1500m³ (25% of total
production)
© Fraunhofer ISE
Mega plants
> 1Mio m³/Tag
Small scale,
distributed systems
< 1000 m³/Tag
Development of the global desalination market
The utilization of renewable energy for desalination is
of increasing interest!
Water shortage and high
solar yield are
geographically correlated
Example:
The production of 1m³ of
fresh water by solar
desalination requires 5 to
10 m² of PV
© Fraunhofer ISE
Overview on desalination technologies
Basic set up of a Multi Effect Desalination (MED)
Cooling blow down
system
Cooling
Thermal energy input ~50 – 60kWh/m³
Sea water at 20 – 35°C
Electrical energy input
Steam at 70°C
0.08 - 0.1 t/tproduct
1.5-2.5kWh/m³product
Number of effects 2 -20
Energy demand
Investment costs
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Overview on desalination technologies
Principle design of a CSP – MED plant
Fossil
back up
Heat
storage
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Overview on desalination technologies
Basic set up of a Reverse Osmosis (RO) system
60 – 80bar
Electricty
3.5-6 kWh/tproduct
Pressure recovery
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Overview on desalination technologies
Basic set up of a Reverse Osmosis (RO) system
PV-RO - stand alone system configuration for small scale application
© Fraunhofer ISE
Overview on desalination technologies
Basic set up of a Reverse Osmosis (RO) system
PV-RO – grid connected system configuration for large applications
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Overview on desalination technologies
Basic set up of Membrane Distillation system
Driving force:
Difference of water vapor
pressure between both
membrane boundary layers
Hydrophobic
Membrane
Evaporator
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Condenser
Overview on desalination technologies
Basic set up of Membrane Distillation system
Driving force:
Difference of water vapor
pressure between both
membrane boundary layers
© Fraunhofer ISE
Overview on desalination technologies
Renewable energy sources for desalination
RO: Reverse Osmosis
ED: Electro Dialysis
MSF: Multi stage flash
MED: Multi Effect Distillation
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VC: Vapor Compression
STIL: Simple Solar Stil
MEH: Multi Effect Distillation
MD: Membrane Distillation
Decentralized distributed water supply systems
versus centralized systems
Decentralized water supply
Centralized water supply

Low water production costs

Minimized distribution costs

Large urban communities can be
supplied with water

Water supply to remote regions

Minimized distribution grid but
maintenance of system is difficult


Financing is possible since successful
business models exist

Complex, expensive, lossy distribution
grids are required
© Fraunhofer ISE
Financing of systems difficult since
attractive business models do not
exist
Solar energy as prime mover for desalination
systems
Decentralized water supply
Centralized water supply

Stand alone solar only supply is
challenging since large scale energy
storage is expensive

Solar energy can be used efficiently
as fuel saver

100% coverage by solar energy
possible in average annual net
balance in grid connected systems
© Fraunhofer ISE

Full coverage by solar energy in
stand alone systems possible –
further development for cost
reduction

Very remote regions can be reached

CAPEX is high but levalized costs of
water can be the cheapest option
Fraunhofer ISE activities on solar desalination
Conceptual design of CSP + Desalination plants
Application :
 Solar thermal power plants with large scale desalination plant for energy and
water supply to coastal cities
 Fresh water production for irrigation in agriculture
Challenges:
 Locations which provide favorable conditions for CSP and desalination are
limited (CSP+MED requires co-located installation, dislocated installation for
CSP – RO is more flexible)
 Intermittent operation is technically difficult and economically inefficient,
storage or fossil backup is necessary
 Piloting and demonstration is costly due to required size of plant
© Fraunhofer ISE
Fraunhofer ISE activities on solar desalination
Conceptual design of CSP + Desalination plants
Approach:
 Development of simulation models
 Conceptual design of components and systems
 Techno-economical evaluation of system designs and boundary conditions
© Fraunhofer ISE
Fraunhofer ISE activities on solar desalination
Development and piloting of solar driven stand alone
desalination systems
Application:
 Decentralized distributed villages and settlements
 Islands with shortage of fresh water
 Disaster relief
Challenge:
 Adaptation of RO system design to intermittent energy supply
 Technical robustness with respect to changing raw water composition
 Long term operation with minimized maintenance needs
 Minimization of water production costs (Capex – Opex)
 Consideration of socioeconomic boundary condition
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Fraunhofer ISE activities on solar desalination
Solar PV driven RO plant
designed by Fraunhofer ISE
and tested in Cyprus
filtration
desalination
© Fraunhofer ISE
Fraunhofer ISE activities on solar desalination
Solar thermally driven MD systems developed and tested
by Fraunhofer ISE in different locations
Gran Canaria Spain
Pantelleria Italy
Amarika Namibia
Solar collector : 180m²
Waste heat from power plant
Solar collector: 225m²
Nominal capacity: 5 m³/day
Nominal capacity: 5m³/day
Nominal capacity: 5 m³/T
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Summary of our capabilities in desalination
 Basic research on membrane
performance and reliability
 Development of new membrane
based desalination modules
 Development, installation and
evaluation of lab to pilot scale
desalination systems
 Design study and evaluation of CSP
connected desalination systems
 Conduction of techno-economical
studies for the evaluation of
renewable driven desalination
systems
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Summary of our capabilities in water treatment
Solar PV driven stand
alone ultra filtration (UF)
system for purification of
contaminated surface
water
 Capacity: 0,8 – 50 m³/day
 Modular and scalable
 Long term stand alone operation
with minimum maintenance needs
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Dezentrale Entsalzung und Trinkwasseraufbereitung
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