~ Pergamon Renewable Energy, Vol. 12, No. 4, pp. 351-367, 1997 © 1997 Elsevier Science Ltd All rights reserved. Printed in Great Britain PII: S0960-1481(97)00063-3 096(~14Sl/97 $17.00+0.00 ECONOMIC ANALYSIS OF A SOLAR ASSISTED DESALINATION SYSTEM SOTERIS KALOGIROU Higher Technical Institute, P.O. Box 423, Nicosia 2152, Cyprus (Received 30 May 1997 ; accepted 14 August 1997) Abstract--This paper deals with an economic analysis of a solar assisted desalination system. The analysis is carried out for four types of applications, two domestic, a hotel and a village. It is shown that solar desalination is viable for the two bigger installations (hotel and village) with water prices below C£0.89/m 3. It is also shown that the water cost is insensitive to the changes in method of payment or to small variations in direct costs. It is not worth operating the desalination system solely on solar energy due to the high cost of the desalination system and the diurnal nature of the solar input which implies high percentage of inactive time. © 1997 Elsevier Science Ltd. 1. INTRODUCTION Water is essential to life. The importance of supplying hygienic potable water can hardly be overstressed. Water is one of the most abundant resources on earth, covering three- fourths of the planet's surface. Ninety seven percent of the earth's water is salt water in the oceans, and 3% fresh water. This minute percentage of the earth's water is in ground-water, lakes and rivers, and this water supplies most of the humanity. However, the rapid industrial growth and population explosion throughout the world has resulted in a large escalation of demand for fresh water. The problem is further heightened by the pollution of the rivers and lakes by industrial waste and sewage discharged. On a global scale man-made pollution of natural sources of water is becoming the single largest cause for fresh water shortage [1]. The only inexhaustible sources of water are the oceans. Their main drawback, however, is the high salinity of sea-water. It would be attractive to tackle the water shortage problem with the desalination of such water. In this paper the economics of a solar assisted desali- nation system is analysed. Cyprus, being a relatively small island in the north-eastern part of the Mediterranean Basin, with no permanent rivers, and limited ground-water resources, relies entirely on the annual precipitation for its survival. It is evident from the precipitation records available that every 5.4 years there is a drought with precipitation of less than 390 mm [2]. An attempt was undertaken by the Government of Cyprus to solve the problem by building dams and associated reservoirs. This is a correct measure but by considering the fact that to date the maximum water quantity collected is just 74% of the overall dam capacity the erection of more dams is questionable as the dependence on the weather is 351