20 March/April 2012 | Renewable Energy Focus

focus:PerspectiveInsights on renewables

Demand for water is increasing

rapidly. Some forecasts foresee €400-

€500bn of investment per annum

- just to keep up with this growing

demand.

Seawater desalination will form an

increasingly important part of coastal

water systems (where much of the

population growth takes place) as an

abundant source of water. And this

is already happening: In recent years

the use of desalination technologies

in extracting potable water from sea-

water has spread beyond the affl uent

and desert-surrounded locations in

the Middle East - and a few loca-

tions in California and Australia - to

major population centres in Southern

Europe, India, East Asia and Africa.

In Southern Europe for example,

Barcelona, Malta and Cyprus already

source the majority of their potable

water from desalination treatment

plants, while recent investments in

Israel have seen more than half the

country’s water supply come from

desalination sources.

Meanwhile, a desalination plant

launched in 2010 in Chennai, India

provides potable water for 2.5 million

people.

What is the link to renewable energy?

The key challenge to deploy-

ing desalination is in the cost of

energy required. The current lead-

ing desalination processes require

large amounts of energy to either boil

seawater (MFS technology), or push

it through sophisticated membranes

(RO technology). It is estimated that

28%- 50% of the total cost of running

a seawater desalination facility is due

to electric power useage, according to

the WaterReuse Association (see http://

www.watereuse.org/sites/default/fi les/u8/

Power_consumption_white_paper.pdf).

Traditionally desalination plants

have been powered by fossil fuels,

either directly drawing energy from

the grid, or co-locating the plants

close to coal- or natural gas-powered

plants. It stands to reason that the

global scale up of desalination tech-

nology driven by the use of fossils

as the primary fuel source is both

extremely expensive — leading to

unaff ordable increases in water cost

to societies — and highly polluting.

For instance in the United Arab

Emirates (UAE), up to 3.5% of the

total electricity produced goes towards

desalination. And continued increases

in power generation capacity are

needed to keep up with the growing

water demands of its growing popula-

tion – not to mention industrialisation.

While thus far increased desalination

electricity requirements have been met

with natural gas power, the invest-

ment and running costs are increasing

rapidly. In Abu Dhabi alone the annual

cost of building, maintaining and

operating desalination plants is due to

reach US$3.22bn by 2016 (see http://

www.emirates247.com/business/economy-

fi nance/uae-desalination-plant-spending-to

-jump-300-2010-10-12-1.302849).

So could the powering up of desali-

nation plants with renewable energy

sources be a logical next step in the

development of seawater desalination?

Desalination: new frontier for renewable energy?

WATER SYSTEMS around the world

are under increasing pressure due to

demands from continued industri-

alisation and urbanisation; growing

populations; and increasing pressure

on agricultural systems. This is driving the early stages of

a revolution in the technologies and business models used

in the water industry. Desalination is already part of this

mix, but could the technologies’ high demand for energy

open up a new market for renewable energy technologies?

In recent years the use of desalination technologies in extracting potable water from seawater has spread beyond the affl uent and desert-surrounded locations in the Middle East - and a few locations in California and Australia - to major population centres in Southern Europe, India, East Asia and Africa (image shows plant in the Caribbean).

Insights on renewables

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Perspective

21March/April 2012 | Renewable Energy Focus

Until a few years ago the high cost

of renewable energy and the energy

ineffi ciency of the available desalina-

tion technologies made such integra-

tion unfeasible on a large commercial

scale, even though it may have been

possible on a smaller scale (island

developments for example).

Yet in recent years, solar and

wind power costs have come close to

grid-parity precisely in some loca-

tions where seawater is plentiful, and

frequently where there is a freshwater

shortage. At the same time, continued

innovation in desalination technolo-

gies is contributing to the improved

effi ciency of desalination processes.

Research over the past two years

– undertaken by CambridgeIP - has

shown steady progress in making the

desalination technologies more energy

effi cient, as well as increasing the

maturity of direct integration technol-

ogies (see box – About CambridgeIP).

Evidence of innovation and implementation

The integration of desalination

processes with energy sources can be

divided between those:

• Using mechanical power - for

instance solar heat or industrial

processes waste heat; or pressure

from wind or wave power (so called

direct integration), and;

• Using electricity generated from renewable sources to power the

desalination plant (or ‘indirect

integration’).

In both these areas we have seen a

steady acceleration of inventive activ-

ity and deployment of technologies, as

follows:

Industrial processes integrationA number of companies have

developed desalination technologies

intended for direct integration with

solar or waste heat using low-tem-

perature thermal processes - such as

multi-eff ect humidifi cation (MEH) or

solar multistage condensation evapora-

tion cycle (SMCEC).

For instance US-based Altela Inc. has a modular off -grid product operat-

ing on solar thermal energy or waste

heat. Examples of its application to

date include the treatment of waste

water from shale gas extraction.

Other companies such as Ger-

many’s TerraWater and France’s

TMW are developing similar systems

for integration with solar thermal and

waste heat energy.

Solar PV integration Meanwhile, Swiss-based Swis-

sInso has developed a solar-powered

Reverse Osmosis (RO) water purifi ca-

tion system capable of producing up

to 100m3 p/day of pure drinking water

from brackish water or seawater (see

http://www.swissinso.com/en).

The system has been deployed in

rural or remote off -grid locations in

West Africa and the Middle East, and

can integrate off -the-shelf solar PV

and Reverse Osmosis technologies. The

container-based product is modular

and mobile, and contains all the neces-

sary components on delivery that can

be assembled locally. It also contains

a back-up diesel generator in case of

solar PV failure or insuffi cient power.

And a research collaboration

between MIT and King Fahd Univer-sity in Saudi Arabia has developed a

modular Solar PV - RO unit, which

can be used in emergency relief opera-

tions or at the household level.

Wind power integrationBoth Aerodyn and Enercon have

in the past developed integrated wind

energy and desalination units. The

unit developed by Aerodyn works on

About: Ilian Iliev works for CambridgeIP. He is a serial entrepreneur and economist. Ilian has a wide experience in IP and technol-ogy strategy, innovation policy and innovation fi nance.

About: Helena van der Vegt is a Senior Associate with CambridgeIP and leads on projects in the energy and cleantech fi elds. She has worked with multinationals, SMEs, start-ups and public sector organisations, providing advice on R&D and IP strategy throughout technology and innovation lifecycles.

About CambridgeIP

The company has worked with

organisations like the Interna-tional Renewable Energy Agency

and the World Intellectual Prop-erty Offi ce to build a patent and

technology database of more than

4,500 desalination-related inven-

tions (see Van der Merwe, Iliev et

al. (2011), Desalination Technologies

and the Use of Alternative Energies

for Desalination) - as well as 900

inventions relating to the integra-

tion of desalination and renewable

- (see chart in this article). Such

technology information librar-

ies can be used by inventors and

acquirers of technology alike to

identify cutting edge technologies,

identify collaboration partners

and also understand the scope for

innovation in a sector. And it can

also provide an early indicator

of accelerating activity. The full

report can be found here – http://

www.cambridgeip.com/water (note –

readers can click on this link from the

digital issue of the magazine).

Figure 1: Desalination technologies

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22 March/April 2012 | Renewable Energy Focus

mechanical vapour compression (MVC)

technology, using the kinematical

energy of the wind turbine directly to

drive the compressor of the evaporation

desalination plant. And Germany-based

engineering company Synlift Systems has implemented pilot wind-powered

desalination units in the Gulf region,

which integrate off -the-shelf wind tur-

bines and RO desalination technology.

Wave power integrationThe Australian wave energy com-

pany Carnegie Wave Energy Ltd has

combined its wave energy technology

with RO desalination by using the

pressure generated from wave energy

to drive the RO process. Carnegie’s

CETO 3 wave energy product has been

shown to deliver sustained pressures

capable of driving seawater reverse

osmosis for commercial scale plants.

Future technologiesIn addition to the technologies men-

tioned above, there are also a number

of other desalination technologies

under late stages of development

which, once implemented, could be

natural partners for renewable energy

sources, and could even transform

the economics of desalination. For

instance, the crossover of membranes

with nanotechnology is resulting in

membranes that are more effi cient

and more durable, leading to further

effi ciency gains in RO desalination.

Looking even further afi eld, com-

panies such as Canada-based Salt-works is looking to altogether more

novel desalination processes that

could result in up to 80% less energy

requirement. Saltworks’ patented

technology is based on the concentra-

tion diff erence between salt water

solutions through a thermo-ionic

process. Building from electrodialysis,

Saltworks’ stack uses ion exchange

membranes to separate solutions and

transfer salt (see http://www.saltwork-

stech.com/press_20110614.php). Low

temperature waste heat from solar

can help drive the system, but the

system harnesses energy captured in

concentrated salt solutions to initiate

salt transfer.

Saltworks has already delivered

a remote operated desalination unit

to the Canadian Department of National Defence. And the technology

will soon be tested by NASA Ames Research Centre, with hopes that it

could be used on board the Interna-

tional Space Station (ISS) (see http://

saltworkstech.com/media.php).

ConclusionThe integration of renewable

energy with desalination could trans-

form the economics of water supply in

coastal areas. This is already happen-

ing for remote/off -grid and “water-

poor” island locations.

And while potable water is the

primary usage of desalination, low-

cost, sustainably-powered desalina-

tion raises the prospect of supporting

agricultural development in previously

unarable regions (such as through

micro-irrigation), as well as improving

the sustainability of water-intensive

manufacturing operations such as in

food and beverages. This also provides

renewable energy technology and proj-

ect companies with a growing market

niche, where the economics may be

better than that of the mainstream

electricity market, and which could

allow market entry into the value chain

of major industry players.

Online: renewableenergyfocus.com

Using CPV to deliver fresh waterhttp://tinyurl.com/cytj9w4

Utility-scale solar PV project under way in Australiahttp://tinyurl.com/bmfrvgg

Figure 2: Number of patent families over time for desaliantion technologies and their integration with renewable energy

The key challenge to deploying desalination is in the cost of energy required. The current leading desalination processes require large amounts of energy to either boil seawater (MFS technology), or push it through

sophisticated membranes (RO technology).

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