Desalination And The Continuity Of Human Civilization

Water, Population and Development

To support the growing human population, which has already crossed the 6 billion mark and is expected to reach 8.3 billion in 2025, and 10 - 12 billion in 2050, humanity must rely on industrial development within a framework of socio-economic development. The Dublin Principles and also Agenda-21, particularly its Freshwater Chapter, make it clear that water is a key to sustainable development. The World Health Organization (WHO) has estimated that 1000 cubic meters per person per year is the benchmark level below which chronic water scarcity is considered to impede development and harm human health.

97.5% of the total global stock of water is saline and only 2.5% is fresh water. Approximately 70% of this global freshwater stock is locked up in polar icecaps and a major part of the remaining 30% lies in remote underground aquifers. In effect, only a miniscule fraction of freshwater (less than 1% of total freshwater, or 0.007% of the total global water stock) that is available in rivers, lakes and reservoirs is readily accessible for direct human use. Furthermore, the spatial and temporal distribution of the freshwater stocks and flows is hugely uneven.   (See   Sustainability of Desalination Systems)

Hydrologists estimate the average annual flow of all the world's rivers to be about 41,000 km3/yr. Less than a third of this potential resource can be harnessed for human needs. This is further reduced by pollution such as discharges from industrial processes, drainage from mines and leaching of the residues of fertilizers and pesticides used in agriculture.

Sun is the Source of Renewable Energy and the Oceans are a Major Alternative Source of Water

Just as the sun is an alternative source of energy to meet future demands, the oceans are an alternative water resource. However, extraction of fresh water from the oceans requires significant development of desalination infrastructure. Desalination is very energy-intensive, and sustainable energy systems urgently need to be developed. The most arid lands are also those blessed with abundant solar energy and this needs to be exploited for large-scale production of freshwater from the oceans.

Human engineered desalination systems actually mimic the hydrologic cycle, which is itself a grand process of distillation. If these systems are driven by the sun, they will augment the fresh water supplies of the global hydrologic cycle. The resulting process will add a human engineered, sustainable and very controllable, contribution to the natural hydrological cycle. There is a clear need for further research and development, and adequate funding towards this end. The oil-rich and water-poor Arab nations must, and they can afford at present, take significant steps in this direction. They are strangely living in a false paradise without adequate concern about the inevitable crisis they will have to face in the not too distant a future when their oil reserves will be exhausted.

Commercial Potential of Desalination

The world has seen a 22-fold increase in desalination capacity since 1972 and the figure continues to rise. Desalinated water is still expensive and one way of bringing down the cost is by building large-scale units with appropriate technology. There were ambitious studies in the 1960s and 1970s on large-scale thermal desalination units with a capacity of 50 million gallons per day, but little came of this. Economics of desalination continues to be based on a flawed accounting system, which disregards fundamental life support systems.

Remember that main stream economists (neoclassical economics) are still unwilling and unable to internalize external costs in marketprices. However 'natural capitalism' would certainly mean that natural ressources and environmental costs need to be part of the economic calculations. See The Economics of Life and Death (John McMurtry ) and Energy Economics: Deep Breath or http://www.eroei.com/articles/the_chain/energy_economics/

The 'dismal science' of economics has developed in isolation from other sciences, in particular those that concern the living world. As a result, what is necessary to preserve our planet's life processes is all too likely to be 'irrational' from an economic standpoint. The choice is simple: to rewrite economics or to destroy the natural world". (Goldsmith, 2003)

The current structures of the energy market and domestic energy prices are major barriers to increasing the use of renewables. However, policy dimensions, and cultural issues all are challenges confronting decision makers worldwide at local, regional and global levels. As it is well known that oil and gas are running out and soon or later, every type of fossil energy will run out – including fossil uranium ore which is used by nuclear power plants.

According to the findings of the Intergovernmental Panel on Climate Change (IPCC), climate gases will have to be reduced by at least 60 per cent by 2050 if earth ecological system collapse is to be avoided.

The sun, with its by-products (renewable and non-renewable resources) supplies our planet with many times more energy per day than the earth consumes, as for example if we assume the world energy demand for electric power in 2004 is about 14.5 Terawatts and considering the total solar energy potential of earth is about 165000 Terawatts the result is about 11400 times the world energy demands. If we consider just 3% of the Arab region surface area, it is equivalent to about 127.7 Terawatts. This is indeed what may be classified as true sustainable wealth of the Arab region, however the sad story is that Arab governments have unfortunately failed to realize the proper utilization of this enormous clean energy.

The apparent abundance of fossil fuels brings the energy prices deceitfully to low levels that are surely unsustainable. This is tantamount to robbing future generations, and is in breach of the principle of intergenerational equity. The result is a situation in which decision makers have been satisfied with a performance ratio of around 6 to 10. With suitable motivation, the industry should be capable of achieving performance ratios of 20 or even 30 for thermal desalination processes.

Market forces tell us that the costs of conventional water supplies from freshwater flows are expected to rise sharply. In urban water management, most of the cost goes into distribution and sewage treatment, whereas a significant decline has been noticed in recent years in the costs of desalination. In the last fifty years, a reduction of nearly 90% has been achieved in energy usage for seawater desalting. By 2025 the costs of desalination are likely to be of the same order as those of urban water supply and sanitation. Furthermore, water quality improvement can be achieved at the local level as well as by means of large industrial plants. Of late, there has been an increasing focus on the installation of small-scale distillation plants at the community and household level, in order to remove contaminants in supply lines. Thus small-scale distillation units for water purification (particularly solar based ones) offer good commercial potential.

Desalination and Sustainable Development:

Desalination has already made a major contribution to quality of life in the most arid regions of the world, particularly the Arab region and North Africa. Without desalination, many of these regions would have remained uninhabited. With rising global demand, uneven distribution of freshwater and increasing population, Malthusian apocalypse would have already come true. Desalination technology is providing safe drinking water even to some 'water-rich' nations where pollution reduced the quality of natural waters. Thus, as a means of augmenting fresh water supplies, desalination contributes significantly to global sustainability.

The desalination associations and institutions have a pivotal role to play here, encouraging the scientific and industrial communities to make efforts to meet world water requirements through environmentally sustainable technologies. Investments in this direction are not impossible; the annual global expenditures for arms and advertisement are currently about US$780 billion (SIPRI 1998) and US$435 billion respectively. Just 1% of this over ten years would be a prudent diversion of resources enough to provide safe water and decent sanitation facilities for all human beings.

Solar Energy for Desalination in the Arab World

The Arab World (AW) stretches across well over 12.9 million square kilometers of area including North Africa and the part of Western Asia known as the Arab Region. This is a region of highest water scarcity and arid climate with annual precipitation ranging from 100 mm to 400 mm. The total annual renewable water resources (TARWR) vary tremendously between the different Arab countries ranging between 0.1 km3/yr for Qatar and 75 billion m3/yr for Iraq. With a current total population of around 325 million people and a very high growth rate of 2.7%, the per capita share of TARWR has dropped well below the UN threshold for water poverty (1000 m3 per year) with most of the Gulf Arab countries reaching per capita TARWR below 200 m3/yr.

In order to meet the rising water demand required by an expanding population and developing economy and to fill the gap between supply and demand, it was found that desalination of seawater and brackish water could provide a portion of the shortfall in water supply. The growing technology of desalination is currently providing enormous quantities of water to meet the escalating needs for domestic and industrial sectors in many water scarce Arab countries. Based on recent published estimates, the current water deficit in the region amounts to 60 billion m3/year and this is expected to grow to 160 billion m3/year by 2050. A significant amount of the current 60 billion m3/year deficit is provided by desalination and it is expected that desalination will also provide more to make up for the 160 billion m3/year needed by 2050.

Desalination processes, however, are energy intensive and are responsible for a good portion of GHG emissions in the region. To produce 1 m3 of desalted water from a typical cogeneration plant results in 12 kg of CO2 gas emission (at an energy consumption rate of 24 kWh/m3 using thermal processes). The current CO2 emission due to desalination can therefore be estimated as 720 million ton CO2 per year. With business-as-usual, this amount is expected to increase to 1600 million ton CO2 by 2050. This is an unacceptable situation and cannot be allowed to continue from both population health viewpoint and from the global warming point of view.

Fortunately, the AW is blessed with a renewable energy resource that is matched only in very few areas of the world, namely, Solar Energy. The region lies in the so called “sun belt” area which is the area of the globe that has the highest solar radiation intensity. The solar radiation intensity in the region lies in the range 2000 – 2800 kWh/m2 yr. The major advantage of using solar energy for desalination is that the GHG emissions produced by solar desalination plants is almost zero and the resource is available almost everywhere in the AW. The current issue of high capital cost for solar collectors and solar PV fields is a temporary problem that will be eventually solved by new technology, mass production and engineering innovation.

The total installed capacity of desalinated water systems in the world in 2006 was about 37 million m3/d, which is expected to increase drastically in the next decades. The dramatic increase in desalinated water supply will create a series of problems, the most significant of which are those related to energy consumption. It has been estimated that production of 25 million m3/d requires about 338.4 million barrels of oil per year (considering specific energy consumption 24 kWh/m3). Even if oil were much more widely available, could we afford to burn it on the scale needed to provide everyone with fresh water? Given the current understanding of the greenhouse effect and the importance of CO2 levels, this use of oil is debatable. Thus, apart from satisfying the additional energy demand, environmental pollution would be a major concern. If desalination is accomplished by conventional technology, then it will require burning of substantial quantities of fossil fuels]. Fortunately, the Arab world (AW), as many other regions of the world, is blessed with a non-polluting resource of energy and is renewable, namely Solar Energy.

Problems relevant to the use of fossil fuels, in part, could be resolved by considering possible utilization of renewable resources, such as solar energy. In fact, most developing countries, with vast areas but having no access to the electric grid, appear to be well versed in renewable energies. Such sources, able to be used directly even at far remote and isolated areas, could be exploited to power low to medium scale desalination plants. A meaningful contribution from the above mentioned environmentally friendly energy resources would certainly be to extend the foreseen duration of fossil fuels store as well as attenuate the socially negative impacts caused by sudden increases in oil price. It is to be noted that nearly 3 kg of CO2 generated for each m3 of water produced (at an energy consumption rate of 6 kWh/m3 with the alternative desalination technology currently used on large scale) could be avoided if the conventional fuel is replaced by a renewable one.

Security policy should be Renewable Energy Policy

Our dependency on exhaustible fossil and uranium resources leads to the vulnerability of societies. Remember that there are many hidden costs associated with fossil and nuclear energy such as, undermining health, destabilizing the climate system, disposal of radioactive nuclear waste and pollution of water resources. This may lead to irreversible damage to Earth's Life Support Systems. Global life-support systems, incorporate the environmental resources (healthy environment) that sustain the economy as well as those - such as water and air , that support life on earth . At present, critical stress suffered by our environment is manifest in the air, water, and soil, our climate, and plant and animal species. Should this deterioration be allowed to continue, we can expect to alter the living world to the extent that it will be unable to sustain life as we know it. Just imagine the enormous expenditures on international security associated with safeguarding of fossil and atomic fuels including processing. All these are bad enough but an even worse aspect of nuclear technology is the creation of massive security risks such as nuclear weapons proliferation and nuclear terrorism. All of the financial expenditures should wisely be used to promote the use renewable energy resources for eternal peace and protection of life support systems.

Therefore humanity should consider seriously the total replacement of fossil and atomic energy by renewable energy in the next 40-50 years. Atomic and fossil energy prices will inevitably increase due to the exhaustion of natural resources as well as the additional costs from environmental damages. Renewable energy prices will continue to drop due to the increase in mass production and improvement of technology. As there are no fuel costs for wind, solar, the renewable energy system is more cost effective, perhaps exception to this is biomass. However Most of biomass is the energy source for the bottom half of the global economic ladder, three billion people or so. A great deal of that was unsustainably burned vegetation, cow dung, and other materials that are used where modern energy is not available or affordable (Richard Smalley).  See also  Solar Energy-The Availability Perspective for Meeting the Future Energy Demands of the Arab as well as the Entire World.

Let us hope that the entire world rises to meet this requirement of faith in the survival of life on earth.

Darwish Al Gobaisi

Please download the presentation by Prof. Richard E. Smalley (Nobel Lauriate), on  Humanity's Top Ten Problems for next 50 years

See also   Rick Smalley - Solar Energy and a New Future

See also   Rick Smalley - The Energy Challenge - The Energy Solution