Renewable Desalination March 2013
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In 2012, the United Nations estimated global water usage to be about 9 billion cubic meters per year, consuming 54% of all the accessible freshwater in rivers, lakes, and underground aquifers. The amount of water in use globally has been growing at more than twice the rate of population increase in the past century. As a result, the United Nations estimates that by 2025, demand for water will have increased by 50% in developing countries, with 1.8 billion people living in countries or regions with absolute water scarcity.
The growing scarcity of freshwater has led to an increasing investment by governments and companies in desalination technologies to provide freshwater for growing populations and increasing agricultural demand. Traditionally, desalination plants have become established in semiarid coastal regions—such as the Middle East, Australia, and California. For many of these regions, the use of desalination technology has become an integral part of government policy and water security. However, desalination is an energy-intensive process, which not only adds to the cost of water provision but also has led to serious concerns about energy consumption and environmental impact. For example, the Saline Water Conversion Corporation (SWCC) of Saudi Arabia burns about 350 000 barrels of oil a day in order to produce two-thirds of the country's daily water supply. World economists have gone so far as to predict that if oil continues to serve for water and energy production, Saudi Arabia may become a net importer of oil by 2030.
The Middle East and North Africa region has for a long time been the heartland for desalination technology and accounts for about 38% of the world's desalination capacity. Of the various types of desalination technology currently in use around the world, reverse osmosis (RO) is the dominant system, accounting for 60% of global capacity. Therefore, any growth in the desalination market is likely to have a significant impact on the demand for RO technologies and membrane development.
According to market-data-analyst CambridgeIP, about 20% of all desalination patents in 2012 referred to their integration with a renewable energy source. One of the major contributing factors to such integration is that, against a backdrop of rising global fuel prices, the cost of some renewable energy technologies has fallen, significantly increasing their competitiveness as an energy source. Energy-importing countries such as India and China that are reliant on the volatile global fuel markets represent a large potential market for renewable desalination and membrane technology. Renewable energy systems are in many ways the perfect partner for desalination; regions that require desalination plants tend to be either arid regions with high solar intensity or remote regions—such as islands—that require an off-grid solution to their poor electrical-generation and -distribution infrastructure. Examples of renewable desalination projects from around the world, as well as future concepts in energy integration, follow.
The Middle East
The need for the sustainable production of potable water in the Middle East is one of the "most pressing issues in the world," according to Masdar, the clean-tech institute in Abu Dhabi, United Arab Emirates (UAE). In January 2013, Masdar launched a pilot program to test and develop new energy-efficient seawater-desalination systems that can be powered by renewable energy sources. The initial pilot project will last for three and a half years, after which Masdar hopes to develop a commercial-scale project by 2020.
The UAE is not alone in the Middle East in setting out long-term goals for renewable desalination. In the next 20 years, the SWCC aims gradually to convert all its desalination plants to run on solar power, in line with the government policy to install 41 GW of solar power by 2032, and from 2020 the SWCC is planning for all new desalination plants in Saudi Arabia to run on solar energy.
In fact, the world's first large-scale solar-powered seawater RO plant has already materialized in Saudi Arabia, close to the border with Kuwait. The Al-Khafji solar-desalination plant, which started production in January 2013, produces about 30 000 cubic meters of water per day serving the town's 100 000 inhabitants and showcases the potential for future renewable energy integration in the region.
The United States
Aside from its use in large-scale industrial installations—such as Al-Khafji—renewable desalination is well suited for smaller off-grid projects that can provide relief to small communities in remote locations. For example, in September 2012, the University of Arizona and the US government's Bureau of Reclamation announced they were developing an advanced solar water-treatment system to provide clean water for the Navajo Nation, a semiautonomous Native American–governed region. Two decades of drought have reduced Arizona's largest aquifer to a mere small fraction of what it once was. The aquifer now lies 120 meters below the surface, with salinity half that of seawater, forcing the Navajo people to drive hundreds of miles every month to collect drinking water. Engineers at the University of Arizona have designed a small-scale desalination plant that uses the energy from solar panels to pump the water up from the aquifer and convert it into steam. They then force the steam through a series of membranes to filter out the salt and other contaminants and collect the purified water in an external condenser. The system is due to come online in early 2013 and should produce about 4000 liters of clean drinking water a day when fully operational.
Australia is currently proposing renewable energy projects for all its desalination plants as a means of offsetting energy consumption. The Wonthaggi plant, in Victoria, Australia, is the newest addition to Australia's desalination program and was complete in December 2012. The Wonthaggi plant is Australia's sixth large-scale desalination plant and has the capacity to provide up to 200 gigaliters of water per year using RO. Energy usage is offset by the Glenthompson wind farm based in Western Victoria.
Although wind and solar are the primary technologies under consideration for renewable desalination, wave energy also holds great potential. In 2010, the Australian company Carnegie Wave Energy tested a proof-of-concept design in a desalination project in Freemantle, Australia. Central to the design was a large buoyant vessel fully submerged in deep water and anchored, via a cable, to a hydraulic pump on the seabed. The vertical movement of the buoy converted the wave energy into transportable hydraulic energy and delivered seawater, under high pressure, directly to an onshore RO-desalination unit. Because of the large volume of seawater pumped ashore, the flow was split, with the excess seawater running back into the sea via hydroelectric turbines generating zero-emission electricity. In May 2012, Carnegie Wave Energy won a government grant to implement its first large-scale demonstration model off the coast of Perth, Australia. It hopes to complete the model by the end of 2013.
Renewable Desalination in Sub-Saharan Africa
In January 2013, the European Union announced that it will contribute €40.5 million in financial support to an RO-desalination project in Djibouti city, Djibouti. Djibouti city is on the Red Sea and the Horn of Africa and has suffered a prolonged drought resulting in extreme water and food scarcity. The situation in Djibouti City is compounded by seawater intrusion into the city's aquifer, leaving the population with no alternative source of safe drinkable water. Recent political instability in neighboring countries and the migration of the rural population into urban areas has led to a 10% to 15% rise in the country's population, accentuating stress on resources.
The money from the European Union is part of the Producing Safe Drinking Water with Renewable Energy program and will assist a multistage strategy to increase the country's independent supply of potable water. The project comprises construction of a new desalination plant capable of producing 45 000 cubic meters of water per day, which will integrate with a 20 MW wind farm. The key feasibility studies for the project were complete in April 2012, and contracts for the first stage of the project are likely by September 2013.
Drought and water scarcity in Africa don't affect just the least-developed countries but reach across the continent from Cairo to Cape Town. Even the most-developed African nation, South Africa, is facing growing water scarcity, exacerbated by periodic droughts and increasing pressure from agricultural and industrial demand. Market analysts at TechSci Research predict that the South African water-desalination market will grow rapidly in the next five years, with a compound annual growth rate of 28%.
In November 2012, South Africa finally got Round 1 of its renewable energy–development program under way by approving $5.4 billion of private investment in 28 projects that will deliver 1.4 GW of generation capacity. Most likely at least some of the next generation of desalination plants will benefit from the renewable energy–development program, either directly in a renewable desalination project or by offsetting energy consumption indirectly.
According to management consultants at Booz & Company, Gulf Cooperation Council countries will invest more than $100 billion in their water sectors between 2011 and 2016. This investment will go not only into the adoption of existing technology but also into membrane research. Therefore, the Middle East is likely to remain central to the continued development and application of renewable desalination and membrane technology for the foreseeable future.
Outside the Middle East, rising fuel costs and environmental legislation will be the principal driver for renewable desalination. Countries—such as China, India, and South Africa—that consume a significant amount of fossil fuels for their energy are likely to increase their level of interest in renewable desalination. Although Asia has been slow to implement renewable desalination, important to note is that in 2012, 25% of China's wind turbines were sitting idle and unconnected to the grid. Such underdeveloped renewable energy projects represent a huge potential market for the integration of desalination projects and could lead to the greater development of some of the more remote regions of China.