“Direct” and socially-induced environmental impacts of desalination

“Direct” and socially-induced environmental impacts of desalination

Desalination 185 (2005) 57–70 ‘‘Direct’’ and socially-induced environmental impacts of desalination G.L. Meerganz von Medeazza Institute for Environm...

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Desalination 185 (2005) 57–70

‘‘Direct’’ and socially-induced environmental impacts of desalination G.L. Meerganz von Medeazza Institute for Environmental Sciences and Technology (ICTA), Autonomous University of Barcelona, Spain Email: [email protected] Received 23 February 2005; accepted 15 March 2005

Abstract Since environmental impacts of desalination processes are intrinsically related to system efficiency, per water-unit produced loads have constantly decreased over the past decades. However, some significant fouls remain. The example of Spain is punctually used throughout this paper, to illustrate the main environmental impacts of the desalination technology. One major concern is the potential environmental impacts caused by extensive brine discharge; unavoidable desalination sub-product that may heavily affect marine biota. Recommendations are outlined to reduce environmental degradation related to hypersalinity. A further drawback is the production of greenhouse gases associated with the required power generation. Environmental loads of any process can be considerably reduced when integrated with renewable energy production systems. After these two ‘direct’ environmental impacts are addressed, some socially-induced factors leading to unsustainable water management are identified. Keywords: Desalination; Environmental impact assessment; Brine pollution; Greenhouse gas emissions; Renewable energies; Integrated water resource management

1. Introduction Desalination has proven to be a readily available way to alleviate freshwater scarcity. During the past decades, technological progress increased process efficiency, and although socio-economically context dependent, desalination turned into an extensively applied solution for an increasing number of regions

around the world, and in particular in various countries of the Mediterranean region [1]. This is notably the case in Spain, where the number of desalination facilities, projected and under construction, has significantly increased in the past years. The recent political change that occurred in this country also offers a perfect discussion frame to review different water resource management options. In this paper,

Presented at the Conference on Desalination and the Environment, Santa Margherita, Italy, 22–26 May 2005. European Desalination Society. 0011-9164/05/$– See front matter Ó 2005 Elsevier B.V. All rights reserved doi:10.1016/j.desal.2005.03.071

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the new Plan Hydrologico Nacional1 (PHN) will therefore serve as a debate ground to analyse current water management trends embedding the desalination technology. The former PHN’s main subproject [2,3] which was to transfer yearly 1050 Hm3 from the Ebro River over a 900 km-long aqueduct to ‘‘water-deficit river-basins’’ has been officially repealed by the new government and previously rebuked by EU disagreements. The present alternative – the socalled Programa AGUA – plans to provide the same flow at a lesser cost, in less time. It is mainly based on a fleet of 14 new Reverse Osmosis (RO) desalination facilities that would provide an additional2 600 Hm3/y. Besides serving as an electoral campaign weapon, the desalination alternative proposed by the new government is a more economic and environmental effective option than gargantuan civil works such as large dams and inter-basin water transfers, which often have striking social and environmental repercussions. Similarly, desalination is often praised as an alternative to fossil groundwater mining or overexploitation of coastal aquifers leading to quasi-irreversible seawater intrusion. These apparent environmental advantages should however be taken with great care as they could easily lead to statements such as the following: ‘‘Despite the environmental impact associated to industrial desalination it should always be remembered that desalination plants are both preserving existing natural sweet water resources and contributing to develop agricultural areas, gardens even forests (in the Emirate of Abu Dhabi) where desert was before. Therefore the question whether desalination plants are environmentally friendly is not really relevant’’ [4; p. 439].

In this paper, various environmental aspects of the desalination technology will therefore be analysed with greater care. 2. A material and energy flow approach Although various desalination methods exist – most commonly, distillation (thermal separation) and membrane technologies- the overall process metabolism is generally the same. Since, from an ecological economic point of view [5], the economic process is seen as an open system (to the entry of both matter and energy) [6], the use of material and energy flow analysis referring to a broad palette of bio-physical indicators- appears as a well-suited methodology to pre-determine and assess environmental impacts. Fig. 1 shows that, when considering the desalination process as a black-box, the overarching principle is to turn a saline solution into freshwater. This requires an energy input and triggers the output of a concentrated saline brine as well as energy-associated green house gas emissions. RO membrane separation is a process based on physical-chemical filtration rather than distillation. Because of its greater IN

OUT GHG

Energy

Desalination Process

Seawater

Freshwater

Brine

1

Spanish National Hydrological Plan. Please note that the figures given by the new Plan are still subject to change. 2

Fig. 1. Overall metabolism of the desalination process (own elaboration)

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efficiency and much lower energy consumption (which in terms of primary energy, is about 5–6 times lower than thermal technologies), RO has become the widespread desalination process, gaining the major share of this market outside the Gulf countries, which continue to use mainly distillation technologies. However, most new desalination plants now use RO and this technology is unlikely to be challenged by any other process in the near future. However, some significant fouls remain, and considering the growing importance of the desalination industry as well as its extensive implementation – in countries such as Spain for instance- those fouls should be carefully assessed. The aim of this paper is to shed light upon the major environmental impacts arising from the technological metabolism outlined above. First, ‘‘direct’’ impacts, such as brine pollution and energy considerations will be discussed. Then, the debate will broaden up to encompass other ‘‘indirect’’ impacts—which could be coined ‘‘socio-economic induced impacts.’’ Nevertheless, since the actual impact magnitude strongly depends upon the process enclosed in the black-box, the in- and output characteristics (i.e. energy source and brine discharge remediation), as well as water management trends, various recommendations can be made to ensure the minimisation of those detrimental effects.

3. ‘‘Direct’’ environmental impacts In this section, the two major ‘‘direct’’ environmental impacts will be addressed: energy and brine-associated pollution. Others, usually more limited or punctual impacts may include risks of accidental spills, noise and visual disturbance as well as interference with public access to recreation areas.

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3.1. Energy considerations When considering energy consumption of desalination processes, water input characteristics are fundamental since the operation pressure of RO systems is a function of feedwater salinity. We can distinguished between water featuring poor salinity (below 2000 ppm); brackish water (typically 2000–10,000 ppm), highly brackish water (over 10,000 ppm) and finally seawater (ranging usually between 35,000 and 38,000 ppm). Under European legal requirements, potable water has a saline content of less than 500 ppm, and the energy required to overcome the osmotic pressure of a saline solution is quite considerable. From thermodynamics, the theoretical minimum to obtain freshwater is around 0.7 kWh/m3 [7]. Back in the 1970s, when the technology started to be commercialised, sometimes well over 20 kWh were required to desalinate one cubic meter of water. This value has been constantly decreasing over the past decades and nowadays, energy use for seawater desalination is in the range of 3–20 kWh/m3, with the older distillation plants at the top end. However, the operational pressure to force seawater through the membrane remains around 70–75 bars. Consequently, desalination is still to be considered as a fairly energy intensive and expensive way of supplying freshwater. As a comparison, 6 kWh are required to lift one cubic meter of water by 1800 m, i.e. higher than any worldwide currently undertaken bulk water transfer [8]. Hence, technological advances have tried to optimise the process. One of the greatest contributions lie in energy recovery devices (multitrain power reduction and retro-fit design schemes with Pressure Exchangers, etc.). By this means a notable reduction of the consumed energy is achieved: the state of the art, commercialised RO desalination processes produce freshwater at an (optimal) energy

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cost lying around 2.5 kWh/m3. So, it seems a feasible target to reach water production at an energy cost of 3 kWh/m3 at global level within the next 10 years and thereby considerably reduce environmental impacts. It should however be noted that this promise may be fulfilled in relative terms but will fail in absolute terms, on the global scale, because of the massive increase in desalination production and subsequently, in the overall energy consumption of this industry. Moreover, considering the low sensitivity reliability of the new energy-recovery devices and accounting for occasional efficiency deviations as well as for additional pumping and distribution costs, the real value (at consumption) is more likely to still be found in the vicinity of 4.5 kWh/m3 of water produced. The desalination facilities of the new PHN will be equipped with the ultimate state of the art technologies; yet the Plan (reasonably) accounts for 4 kWh/m3. The environmental impacts arising from those energy requirements are very much dependent on the energy source used to provide the necessary pressure. In this perspective, the major drawback of the desalination technology is that presently most of its energy derives from fossil fuel burning. Thermo-electric power generation triggers greenhouse gases (further exacerbating climate change – a denounced water-stressing factor) as well as other contaminating airborne emissions: for RO3, typically around 2 kg CO2/m3, 4 g NOx/m3, 12 g SOx/m3 and 1,5 g NMVOC4/m3; for MSF or MED: around 20 kg, 25 g, 27 g and 7 g respectively [9]. Raluy et al. [10] 3 These figures correspond to European average energy production scenario [10]. However, in most countries using desalination, oil shares are generally much greater and processes efficiency lower: those figures can be double as high. 4 Non-methane volatile organic compounds.

carried out a Life Cycle Assessment (focusing on the total impact of a product through every step of its life, from ‘‘cradle to grave’’) of various desalination technologies, which revealed that environmental loads and airborne emissions associated to RO are one order of magnitude lower than those corresponding to thermal MSF and MED processes. Similarly, environmental loads of any process can be considerably reduced when properly integrated with energy production (hybrid systems). The environmental impact is also very depended on the type of energy source. For instance when integrated within renewable energy models, an up to 80–85% reduction of overall environmental loads can be achieved [9]. Water being an essential and scarce resource, and in this case, closely related to energy, which in turn is also a limited resource, it seems indeed obvious that both should be considered and dealt with in an integrated way by cogeneration, combined cycles, etc. Moreover, efforts in minimising environmental impacts should be devoted not only in the direction of decreasing energy consumption, but also in a drastic shift towards less damaging energy production systems. A possible ‘‘impact mitigation technique’’ would consist in allocating sufficiently large carbon sinks to absorb the undesired emissions; a more direct way would be to increase the renewable energy share of the desalination industry. The third way would be to reduce the environmental impacts through tackling directly the water factor. The latter can be done by simultaneously (1) improving the desalination process efficiency5 (while increasing the renewable energy share) (2) reducing the water network losses (3)

5

However, getting closer to the thermodynamic minimum imposed by osmotic pressure principles (0.7 kWh/m3), not much room is left for energy efficiency improvements.

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reducing the water demand and consumption (4) increasing the urban water re-utilisation share. 3.1.1. Oil for water: Although, decreasing marginal energy costs have enabled rapid growth of the desalination option, the energy source plays a fundamental role when determining the sustainability level of the technology. Indeed, relying on an energy-intensive production process for the provision of vital freshwater in a socio-economic system running towards unavoidable cheap energy exhaustion6, seems questionable. Moreover, if this energy originates from non-renewable resources does the desalination option not merely shift problems from one scarce resource (water) to another (non-renewable energy)? The ‘‘oil for water’’ pathology also sheds light on the dangers of extreme foreign and non-renewable energy dependency Society has locked itself in, particularly worrying due to its inherent relation with the vital water resource provision. Considering present Spanish energy production shares, most of the additional desalinated water to be provided by the new PHN would have a fossil fuel origin7. At present, the 750 plants inventoried in Spain have an installed capacity of 400 Hm3/y, providing freshwater to around 2.5 million citizens. The alternative plan that proposes an additional 600 Hm3/y to be provided through desalination within the next 5 years, means that the total amount of 1000 Hm3/y will require over 4000 GWh. Given that each m3

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produced represents around 1 kg of oil equivalent, with such energy consumption, Spain will increase its percentage of CO2 emissions by 4 to 9% (in 2010). Note that in the case of Catalonia, the ‘‘oil for water’’ syndrome should rather be termed ‘‘uranium for water’’, which may contribute to other environmental and health risks, not further discussed in the paper. 3.1.2. The potential of renewable energies The energy-intensive desalination technology remains a costly solution especially for developing countries that do not possess fossil fuel resources. Nevertheless, many arid regions (especially in Mediterranean, Middle East and Gulf countries) have a great potential to cover their water needs with autonomous, stand-alone desalination systems powered by renewable energy units at competitive cost [e.g. 11–13]. Since desalination plants are usually located on the coast of arid sunny regions, the contribution of wind and solar energy becomes an evident partner of the water production industry. However, the main problem that seems to appear at the interface of both technologies is that renewable energy production systems -such as wind turbines or photovoltaic panels- are subject to natural intermittent and variable intensities, whereas desalination processes are designed for continuous steady-state operation. Having said this, one advantage of a coupled renewable energy – desalination system may lie in the fact that while power can hardly be stored, water can.

6

Many experts argue that according to multiple Hubbert curves’ analysis, world production will peak around 2010, approaching the end of cheap oil and subsequently the end of cheap energy as a whole (see refs in [33]). 7 Considering that the actual Spanish electricity production is mainly of thermal (51%) and nuclear (35%) origin.

3.2. Brine pollution Brine is an unavoidable desalination subproduct, which is most commonly discharged into the marine environment. The environmental implications of this highly concentrated salt solution (around 70,000 ppm) on local marine

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ecosystems have been controversially discussed for many years. However, it is now widely acknowledged that extensive brine discharge, as it constitutes a hypersaline layer that sinks towards the seabed due to its greater density, has the potential to heavily affect local marine biota [e.g. 14,15]. Furthermore, with massive development of the desalination activity in the Gulf coast line, environmental damage rapidly became evident and a first report on this matter has finally been published by the UNEP, denouncing the gravity of the problem [16]. Evidently, the magnitude of the environmental impact depends on the characteristics of the desalination process—determining the chemical composition of the produced brine—but also of the natural hydrodynamic and batimetric conditions as well as biological factors of the local marine environment [17]. Additionally to the destructive saline properties of the concentrate, in the case of thermal desalination, the produced brine is usually hotter than the local recipient water body; this has also been shown to cause further environmental damage, especially to fragile ecosystems such as corals. Furthermore, during pre- and post-treatment processes a variety of chemical agents are added to enhance flocculation or prevent foaming for instance, others to avoid membrane deterioration such as biological growth fouling and mineral scaling [18]. Antiscaling agents are mainly polyphosphates or, more widely used, polymers of maleic acid or sulphuric acid; antifouling additives are usually chlorine compounds and antifoaming agents would be alkylated polyglycols, fatty acids and fatty acid esters. At the outlet, those components are discharged along with the brine and certain metals (copper, nickel, iron, chromium, zinc, etc.) derived as corrosion products of thermal processes. Their concentrations and associated adverse environmental impacts depend very much on the

process design. But generally speaking, after the ‘‘marine desertification’’ effect of emitted brines (osmotic stress has the greatest devastating impact particularly on the benthic biota [16]) eutrophication, pH value variations, accumulation of heavy metals as well as sterilizing properties of disinfectants have the most pronounced effects on receiving waters. In the Spanish case, the major threat lies in the loss of the Posidonia oceanica and its associated ecosystem [19]. This concern is especially valid in the desalination-active province of Alicante that features an extensive Posidonia grassland cover. The Posidonia oceanica is a phanerogamae, endemic to the Mediterranean sea, which grassland are of great ecological value and its conservation is emphasised in different environmental legislations8. Besides its contribution to fix sand banks and oxygenate the sea water, Posidonia grasslands host an elevated biological productivity since they constitute the breeding habitat of numerous species. Hence, the loss of Posidonia grasslands decreases, inter alia, water quality, favours sludge formation increases turbidity and sediment transport. Another side-effect is the alteration of the marine food chain by dislodging or eradicating breeding areas of many species. Buceta et al. [20] studied the effects of brine on local Posidonia grasslands and the results of their experiments confirm that the Posidonia oceanica is very little tolerant to salinity increases. Those increments cause growth reduction, permanent leaf fall, appearance of necrosis in the tissues, structural pattern changes of the grassland, diminution in the abundance of the accompanying macrofauna and raise the mortality rates. The sensitivity of frequently found 8

e.g. List of ‘‘priority conservation habitats’’ given by the European Council (Directive 92/43/CEE, 21st May 1992).

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fauna in the Posidonia grasslands (in particular, Leptomysis posidoniae and the sea urchin Paracentrotus lividus) have also been analysed. In general terms, it has been observed that mortality increased parallel to salinity. Mortality increments began to become statistically significant from 40,000 ppm onwards, while for salinities close to 45,000 ppm, 50% of the plants died within the first 15 days. Unfortunately, no study is available on long-term effects of the Posidonia ecosystem subject to hypersalinity conditions. Uncertainties, therefore, remains whether the above-mentioned effects would be accumulative or synergic in chronic situation. Season, temperature, depth variability and light availability as well as other environmental components probably also alter the observed reactions. For instance, plants of greater depth seem much more sensitive. Also, the detrimental contribution of the above mentioned chemical agents (sporadically or permanently found in the effluent brine) remain poorly quantified. 3.2.1. Brine remediation methods It is paramount to avoid brine effluents entering in contact –in their brute form- with sensitive ecosystems. This can be achieved in various ways. For instance, Ferna´ndez Torquemada et al. [21], shed light upon the potential in alleviating possible environmental impacts of brine discharge, through appropriate site selection (hydro-geological, hydrodynamic conditions, local ecological value, etc.), construction planning, process design (desalination technology, production size, etc.) and discharge devices that would ultimately reduce salinity. The latter can be achieved through appropriate mixing and dilution, using the kinetic and potential energy of the effluent, taking advantage of the natural hydrodynamic local conditions or through active mixing mechanisms, such as artificial diffusers [17].

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Although, from basic hydrodynamic principles it is well known that the salinity gradient generally decreases from the outlet pipe, until now, little scientific information has been published about precise ‘‘real-life’’ dilution and mixing behaviour of these discharges [22]. Rapidity of dilution processes depends very much on local hydrodynamic conditions, i.e. proportional to the water column agitation. For every newly build desalination facility, it should be determined at which distance from outlet source total dilution is obtained under various hydrodynamic conditions. Discharging brine in turbulent hydrodynamic conditions (i.e. water bodies featuring waves, currents and super-critical flows) is often recommended. Depending on the seabed geology, the brine solution would ‘‘flow down’’ the batimetric slope; hence, in certain cases, thanks to a precisely determined and well-used topography, Posidonia grasslands—and other sensitive ecosystems generally located close to the surface—might be saved. Finally, reducing brine salinity down to levels where obtained concentrations can be beneficial to other sectors such as aquaculture for instance, present interesting perspectives in view of minimizing environmental impacts of saline emissions. As mentioned before, the concentration of the residual brine is directly proportional to both inflow salinity and to the efficiency of the filtering process, in cases of membrane technologies. One fundamental question is therefore to know which water salinity is to be obtained and for what use. If designed for irrigation purposes, in many cases higher salinities could be allowed (especially when integrative regional policies encourage saline resisting crop agriculture). 3.2.2. Brine taxation Although the UNEP suggested some guidelines and procedures for the disposal of brine according to the land-based-

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sources (LBS) and dumping protocol, aiming at identifying a common management approach in line with the Barcelona Convention [16], so far no legal requirements oblige the treatment of the residue before being dumped back into sea. A debate is currently being held on whether brine discharges should be regarded as industrial waste. According to current economic calculus, untreated sea-dumping seems the most cost-effective way to discharge the produced brine. This calculus might well change, if valuable ecosystem loss (in terms of environmental-service pricing: e.g. sand-fixing –avoiding costly sediment reclamation, filtering and oxygenating properties of the Posidonia oceanica) was to be accounted for. Also, one may wonder what the repercussion on desalination water prices would be if brine was to be considered as an (industrial) wastewater effluent, hence being subject to the Urban Waste Water Treatment Directive (UWWTD) [23], requiring standardised treatment before discharge. Considering that presently half of the Spanish industry discharges its wastewaters without any permit and that Spain remains far from meeting the targets set by the UWWTD despite the large flow of subsidies provided by the Cohesion Fund [24], one can only question the outcome of the brine issue exposed in this paper. It has been shown [25] that economic incentives serving as a policy instrument, such as the polluter-pays principle, are fundamental governance issues to meet eco-efficiency. By contrast, low water pollution levies and absent full-cost recovery pricing schemes may have disastrous effects on both environmental and economic effectiveness. The suggestion is therefore made here to consider brine discharge in the UWWTD.

3.3. Environmental mechanisms

impact

assessment

To conclude the first part of this paper, which dealt with the ‘‘direct’’ environmental impact of the desalination technology, it should be noted that although environmental impact assessments procedures have been proposed [26], standards, codes and technical solutions are still in their early phases. A much needed internationally agreed environmental assessment methodology for desalination plants does not exist at present; however, a new directive on impact assessment -which could eventually also be applied to the desalination industry- is currently being developed. Such legal frame would be essential in decision making processes assessing, for a given situation, the best suited water supply option. Given the forthcoming burst of the desalination activity in Spain, that will unavoidably discharge an additional 730 Hm3/y of hypersaline brine9, construction of every new desalination facility is to be accompanied by a rigorous environmental impact assessment. Considering the outstanding patrimonial and ecological value of the above mentioned ecosystems, their conservation should be highly praised. In any case, when it comes to formulate recommendations about critical threshold values, the precautionary principle [27] should be emphasised to ensure security margins that would guaranty the survival of the affected grasslands. Also, it has been recommended that salinity thresholds should not be given in terms of a referential value but as frequency distribution: for instance, at no point of the grassland should the salinity surpass a salinity of 38,500 ppm in over 25% of the measurements, or 40,000 ppm in over 5% of the measurements [20]. 9

Given that the new plants are to be equipped with RO processes working on a 45/55 (freshwater/brine) efficiency.

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So, given the level of scientific uncertainty the Spanish Mediterranean case is still subjected to, it is deemed necessary not to consider any formulated result as definitive ones. The Programa AGUA should therefore be considered as a life-experiment that ought to acknowledge the concept of irreducible uncertainty arising from socio-environmental complexity [28]. Also, the importance of welldesigned and legally-bound environmental vigilance programmes should be emphasised. Such programmes regularly assess the impact evolution on the local marine ecosystem during the entire life-time of desalination plants. This programme should ensure direct action to be taken at the first signs of environmental degradation to avoid irreversible effects. 4. Socially-induced environmental impacts Beyond the above exposed brine and energy concerns lie more impalpable, and therefore more vicious issues that will be discussed in the last section of this paper. The following socially-induced environmental impacts can be understood as ‘‘unintended purposive action’’ [29], which in the case of desalination may entail perverse effects. The global freshwater scarcity crisis we are facing is the consequence of both population and consumption growth combined with declining natural water resource stocks mainly due to pollution and unsustainable resource exploitation. This results in a generalised deflection towards what can be seen as a social scarcity pathology. As a response to this, on the one hand, there is an urge to increase water supply capacities; the desalination technology offers part of this solutionside. On the other hand, there is a growing recognition of the need for demand based water management to provide sounder options. ‘Water Demand Management’ as suggested by the European Water Framework

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Directive (EWFD) [30] simultaneously rests on the three pillars of sustainability: economic (‘‘full cost recovery’’ principle), social (proactive ‘‘public participation’’) and environmental (aiming at restoring ‘‘good ecological status’’ of water bodies) aspects. The EWFD strives towards re-establishing the balance between supply and demand by providing more goods and services using less water [25]. In Spain, civil society uttered its rising mistrust for wraithlike paternalistic hydraulic policies correcting primarily socially-constructed water scarcities and serving oligarchic interests. A civil movement representing social actors from different fronts cried for a new ‘water culture’ that would acknowledge the multiple dimensions of environmental, social, economic, political, ethical and emotional values of this vital resource. This Nueva Cultura del Agua [31] argues for a fundamental shift from ‘‘hydraulic works promotion’’ towards an ‘‘economic management’’ approach and strives for integrating both socio-economic and environmental aspects. Such demand side approaches aim at minimising the need for additional supplies, trying to avoid ‘‘supply creates demand’’-type vicious circles and, at a global scale, enhanced water access equity. 4.1. Ever growing demands The principle of the domination of nature that led at the end of the 19th and especially during the 20th century to a productivist water management approach results in a well-established hydraulic structuralism, strongly rooted in engineering and technical sciences. This can be particularly verified in Spain that traditionally focuses on water supply; the issue of water quality and pollution only truly appeared on the agenda in the late 1980s. Water in Spain has been a key issue for development and economic growth, especially in the southern and interior regions.

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Water for tourist services and irrigated agriculture have continuously increased demands. Part of this demand has been met by a plethora of large-scale hydraulic works that ‘‘vertebrated’’ and ‘‘re-equilibrated’’ the territorial hydrology system, especially since the 1960s [32]. Say’s Law states that ‘supply creates its own demand, which will exhaust supply’. Although Say verified this principle by looking at the economy on the whole, it may well also hold within the water sector itself. Indeed, it seems that increasing supplies will always be insufficient because they increase demands even faster and that ultimately, supplies will always be fully used up. In such context, it would also be interesting to see to what extent the so-called Jevons’ paradox10 applies to water desalination: do we automatically use more water as desalination gets cheaper? Decreasing production energy costs seem indeed to subsequently trigger a rebound effect on water consumption [33]. Furthermore, the long unquestioned success of the hydraulic structuralism approach produced the sensation that water scarcity problems could be entirely solved by increasing supplies. As this conception spread amongst population and tourist industry, the traditional water culture prudence progressively eroded, generating rising consumption patterns. Ironically, additional supplies seem to create a serious contradiction in which a ‘‘water squander’’ culture -subsequently triggering socially constructed water calamities- increasingly emerges in a natural context of absolute scarcity. As pointed out by Naredo [34], the principal imbalance between water availability and its uses originate when human

10

Jevons, in his book on the Coal Question, pointed out back in 1865, that the higher efficiency of steam engines did paradoxically lead to an increasing use of coal by making it cheaper relative to output (see refs. in [5,33]).

activities are imported to zones without any consideration for their inherent capability to host such social habits. Considering the irrigation quotas of private gardens, Domene and Saurı´ [35] shed light upon the intrinsic relation existing in the Metropolitan Region of Barcelona between level of income, household typology and water consumption. In this perspective, diffuse urban sprawl trends characterise the individualisation of society, agreeing with post-materialist society theories [36]. In this perspective, the ‘‘North Atlantic-type lush green lawn’’ and the ‘‘private swimming pool’’ are to be considered as positional goods [37] in Spain’s Mediterranean context. Similar arguments hold when considering the ideology commonly underpinning the Spanish tourist industry (especially for development schemes such as those planned in the Alicante region) or when analysing—through a Virtual Water approach [38]—intensive irrigated agriculture in the arid Almeria and Murcı´ a regions where tomatoes grown under highly irrigated quotas, embodying 90% desalinated water, are exported to the humid North. The massive tourist industry and agro-business (with its 27,000 ha of greenhouses) to be found in the Almeria region result in an average consumption of more than 3000 l per person per day in one of the areas of Europe with lowest rainfall. Unsustainable local aquifer exploitation and mass-scale subsidies—incentive for inefficient irrigation—are not sufficient any more. Desalination should fill the ‘‘deficit’’. 4.2. Water desalination

uses:

purposes

served

by

In this view, the new Spanish National Hydrological Plan, based on extensive desalination, still maintains water supplies well above real necessities, strongly contradicting the natural aridity context. How does

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supplying ever more water to a desert-type region to satisfy imported recreation habits clearly not adapted to the local host environment, solve drought problems? The main concerns of this paper lie in (1) the indirect growth and consumption stimulation effect that the additional desalination facilities can hold and (2) the purpose served by those facilities. When production scales are excessive and uses inadequate, do desalination technology lock-ins not turn physical scarcities into social ones? In such case, how different really is the new Plan from the former much contested ideology underpinning the Ebro transfer [39]? Under current plans of massively implementing the desalination alternative without consideration of its questionable uses in the tourist and agricultural sectors, does not the myth ‘‘water for all’’ still prevail; or is it shifting towards ‘‘water for anything’’? Although energy consumption, monetary costs and environmental impacts of desalination may present some clear overall advantages to the former Ebro-transfer option, to what extent do the management trends underpinning the desalination alternative differ from the former PHN? How does it deal with demand and consumption patterns? Indeed, just as in the former Plan, the additional provided water will quench the thirst not only of the intensive plastic-tented irrigation agriculture of Almeria but also of the numerous new tourist developments and golf courses. Although such facilities are to be charged 10 times more for their water than farmers, in this view, would not a widespread implementation of desalination plans still remain in the realm of Increased Supply, clashing with the Nueva Cultura del Agua and the EWFD that insists for desalination to be the solution of last resort? In fact, similarly to gargantuan water-diversion projects, this kind of application of the desalination technology holds the unrealistic hope of a

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supply-side solution, which delays the onset of demand-side based solutions. The divide between different water uses becomes clearer as does the differentiation between ‘‘technological change’’ and ‘‘technological equity’’. Where mismatches exist between desalination serving basic domestic needs and water services for tourism (or water for heavily irrigated agro-business), the ‘‘direct’’ environmental impacts exposed earlier on in this paper become particularly concerning and ethically questionable [40].

4.3. Desalination opening a new commodity frontier? Also, under the increasingly prevailing free market logic, a blind application of the desalination solution (i.e. when the technology is implemented with no consideration of its served purpose) entails the final issue this paper wishes to raise. Considering the limitless amount of seawater readily available along the world’s shoreline, the desalination technology presents an immense economic potential. And since free market principles entailing deregulation, liberalisation and privatisation of urban water supply services have been increasingly impelled under the aegis of the World Bank and the World Trade Organisation, making money out of [free] sea resource could open a new commodity frontier (sea-gold). Is (desalinated) water becoming another bulk commodity (in Wallerstein’s terms) just as oil, gas or copper? According to this logic, desalinated water would be regarded like any other goods of the global market, where its exchange value increases as natural water resources become scarcer. This should be understood as the first steps towards the redefinition of access and usufruct, ever more noticeable within the present context of pillage of water

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resources11. Under this perspective, as long as technology has not reached the point of making desalination cheap enough in the context of growing scarcity, it will remain a fairly uncompetitive option, although this point of profitability seems to have been reached for various countries. The question remains however, whether it may ever serve poorer communities.

Although the ‘‘dry Spain’’ lacks significant naturally present water resources, believing that the desalination technology might definitively eliminate this handicap constitutes a dangerous myth that should be criticised for at least three reasons: firstly, this energyintensive technology is responsible for important carbon dioxide and other Greenhouse Gases emissions, which environmental costs remain uncovered or are unloaded onto the energy sector. Similarly, negative environmental impacts arising from uncontrolled brine discharges are being externalised. Secondly, the current desalination trajectory (ever increasing and primarily based on fossil fuels) supposedly accepts an external strategic dependency, which may trigger some serious problems in the future, especially due to the irreversible nature of its ‘‘lock-in’’. Finally, the desalination technology potentially embodies the risk to render former water saving cultures redundant, nourishing the false impression of abundance, responsible for ever increasing demands and faster spinning of the productionconsumption carousel, subsequently alimenting the two previously mentioned issues. Hence, with blind application of the desalination

technology there seems to be a permissive trend towards a social and environmental dumping phenomena. Even the World Bank [8] seems to agree that desalination should remain a solution of last resort, elected only after all appropriate water demand management measures have been implemented. Ultimately, saving water rather than developing new supplies is often the best ‘next’ source of water, both from an environmental and economic perspective. The belief that solutions to the ecological crisis of ecosystems and the collapse of the water cycle can be solely found in hydraulic structuralism and supply-side approaches should be overhauled. Instead, demand management schemes (economic rationality governed by cost recovery principle—including environmental costs and scarcity value) as well as restoration and conservation strategies (where the insufficient polluter-pays principle should be replaced by the principle of no-deterioration at source) should be implemented within an integrated hydrological basin management approach. From the ethical foundations laid by the Nueva Cultura del Agua emerged the European Declaration for a New Water Culture (signed in Madrid, February 18th, 2005), which recognises the different functions and values of water. Similarly to the way this afore mentioned Declaration is pronged, the purpose served by desalination should be differentiated in: ‘Water for Life’ as a top priority (that should be guaranteed effectively from the human rights12 standpoint), followed by ‘Water for General Interest Purposes’ (preserving health and social cohesion) and finally, ‘Water for Economic Growth’ recognised as a third level of priority (managed efficiently, under

11

12

5. Conclusions

Refer to the special issue of Manie`re de voir (Le Monde diplomatique), ‘‘La rue´e vers l’eau’’, Sep–October 2002; especially articles by Maris (72–76) and Baudru & Maris (77–79).

Access to drinking water and sanitation has been recognised as a Human Right in General Commentary no. 15 of the UN Committee of Economic, Social and Cultural Rights (2002).

G.L. Meerganz von Medeazza / Desalination 185 (2005) 57–70

economic rationality). Acknowledging that scarcity is an inherent characteristic of economic goods and not of human rights, scarcity management should implement savingincentive policy interventions such as properly designed water pricing and tariff structures as an instrument to moderate demand, limiting unreasonable growth. Social scarcity must be managed under economic rationality criteria in order to regulate the demand/supply nexus. State of the art seawater desalination (involving costs around 0.45 E/m3 and energy consumption under 4 kWh/m3) truly offers ‘Water for Life’ perspectives if not high-jacked by ‘Water for Economic Growth Purposes’. So, regardless of the management model (public, private or PPP), desalination should primarily serve its lofty function of meeting human needs rather than human greed, in other words sustaining livelihood rather than satisfying luxury. Acknowledgements The author wishes to acknowledge the invaluable contribution of Dr David Ta`bara, Dr Sybille van den Hove and Dr Joan Martinez-Alier as well as the IQUC scholarship for financial support. References [1] A.J. Medina, La desalacio´n en Espan˜a. Situacio´n actual y previsiones, Paper presented at the Internacional Conference: El Plan Hidrolo´gico Nacional y la Gestio´n Sostenible del Agua. Aspectos medioambientales, reutilizacio´n y desalacio´n, Zaragoza, June 2001. [2] Boletin Oficial del Estado—B.O.E. Act 10/2001 of the 5th of July, the National Hydrological Plan, 161 (2001) 24237–24250. [3] Boletin Oficial del Estado—B.O.E. Act 1/2001 on Water of the 20th of July, 176 (2001) 26791–26817. [4] C. Sommariva, H. Hogg and K. Callister, Environmental impact of seawater desalination: relations between improvement in efficiency and environmental impact, Desalination, 167 (2004) 439–444.

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