5. Cost analysis for desalinated water
Construction and operation of desalination
plants require huge investments which are beyond
the financial capabilities of developing countries.
Based on the published data by the International
Water Supply Association, the annual average
capital and delivery costs for 1 m3 of water ranges
$0.18–1.61 while the annual average maintenance
cost ranges $0.01–0.45.
In the early seventies the major problem facing
the desalination production was the high cost of
the initial capital investment for construction,
operation, and high energy consumption. Ad-
vances in desalination technology over the past
20 years have resulted in higher efficiency and a
consequent decrease in the cost of desalinated
water from about $3.5 in 1979 to $0.55/m3 in
2000. In Saudi Arabia at zero interest rates, pro-
duction costs from MSF units ranges $0.26–
0.98/m3 while from RO units ranges $0.47–0.48
depending on the size of plant. In the UAE the
average cost for MSF ranges $0.67–1.64 while
for seawater RO plants ranges $0.64–2.4/m3. The
dominant cost element on seawater RO desalina-
tion is the energy consumption which accounts
for about 50% of the total cost. Fig. 3 shows the
reduction of desalinated water cost overtime in
the UAE [8]. The analysis of actual bids data for
large MSF desalination plants indicate a large
variance of the capital cost influences the unit
water cost over plant life. For dual propose plants,
cost allocations between water and power provides
an opportunity of cost sharing on unit water cost
[9].
GCC countries use different cost allocation
assumptions, since some considered water as a
secondary product of dual purpose plants, while
others considered it as a primary product. Desali-
nation plants capital and operation cost decrease
significantly as plants capacities increase up to
about 5 MCM of brackish groundwater and
8.3 MCM for seawater. Table 8 summaries the
capital cost of desalinated water in selected GCC
countries. In light of the above, the average cost
from GCC countries using different desalination
process may range $0.75–1.5 for seawater from
large plants and $0.4–1.65 from brackish ground-
water per cubic meter. Table 9 shows the com-
parison of desalination cost with groundwater and
wastewater treatment. In general, water production
costs in GCC countries where desalination is used
extensively are distributed as follows: 38% for
capital investment, 20.5% for energy consump-
tion, 21.3% for labor, 16.2% for maintenance, and
4% for chemicals [10].
Efforts are being made to lower the desali-
nation costs through the use of cogeneration plants