Drinking Water (33 page)
An idea that has no doubt occurred to any entrepreneur clinking ice in a glass on a hot day is towing icebergs. Icebergs float free for the taking near the poles, filled with nothing but clean water. The only trick is getting them from their cold waters of origin to distant ports where they can be used. There have been serious proposals to tow icebergs since at least the 1950s.
The idea is far from crazy, except that pushing makes more sense than towing. Tugboats push massive ships every day in harbors around the world. Indeed, in the North Sea they already push icebergs away from oil platforms. Strong currents flow from both the North and South poles toward the Equator, so most of the navigational force could be supplied by the oceans themselves. Just look at the icebergs from the Arctic that are sometimes carried deep into the Atlantic Ocean, as the passengers on the doomed
Titanic
learned to their dismay.
We don’t see an iceberg moving industry, though, so there are obviously some problems in the way. One concerns melting. Ocean water temperatures increase significantly between the poles and the equatorial regions, as much as 20 to 30 degrees Celsius. Moreover, the iceberg must traverse the high waves and occasional storms of the open ocean, either of which could put pressure on fissures within the iceberg, causing it to break into smaller pieces. A tug can only push one piece at a time, so everything calving off would be left to melt in the open water. Since, as we all have been told, only the tip of the iceberg rides above the water, running aground is also a significant challenge. Moving the iceberg into a shallow port where it could be broken apart and placed in tanks to melt could prove difficult.
Nonetheless, entrepreneurs continue to push the idea. As Georges Mougin, an enthusiastic iceberg proponent, explains, “An iceberg is a floating reservoir. And water from icebergs is the purest water. It was formed some 10,000 years ago.” A sophisticated computer analysis Mougin developed with the aeronautics firm Dassault calculated that a tugboat pushing an iceberg at one knot per hour
could, with favorable currents, move a seven-million-ton iceberg from Greenland to the Canary Islands in 141 days, losing just 38 percent of the bulk en route. This would still leave close to four million tons of frozen water for local use.
Otto Spork sought to avoid the challenges of ocean transport by investing in glaciers, instead. Chief executive of the hedge fund Sextant Capital Management, Spork was confident in his business plan. “Two years ago,” he explained, “we were looking for the next big commodity and settled on water. It was underappreciated, mispriced, and growing scarce.” Spork purchased water rights to three glaciers in northern Europe. Located near ports for transportation ease, he planned to use the melt from one glacier for bottled water and the other two for bulk transport by tankers and water bladders. We will never know if his plan would have worked, however, since Spork and Sextant were found guilty of fraud by the Ontario Securities Commission in 2011.
While attractive in concept, moving water large distances in tankers or frozen in icebergs remains a niche market. The more important strategy to increase sources of freshwater is creating drinking water where we already are. Entrepreneurs and engineers are combining forces to create some exciting technologies. Few of these are likely to become commercially viable, but they give a glimpse of future directions.
While a high-cost and high-tech approach, desalination holds great promise in converting plentiful ocean and brackish water into freshwater. There are a range of desalination processes currently in use. Reverse osmosis forces salt water at high pressure through a series of membranes that filter the salts out. Passing the water through a second set of finer membranes provides an even fresher water. In a sense, this is learning from nature, for the process of natural selection perfected a process for removing salts from ocean water in the evolution of species as varied as albatross and mangroves.
In distillation, salt water is heated and water vapor rises until it meets a cold surface, condensing into drops of freshwater. You may recognize this as the basis of the natural water cycle. Rather
than the sun, clouds, and rain, however, distillation plants rely on industrial boiling and cooling equipment.
The benefits of desalination are indisputable. A secure source of clean water is assured from a virtually limitless supply. There are more than twelve thousand desalination plants in more than one hundred twenty countries. The Middle East accounts for almost three-quarters of global production, most notably in the oil-rich nations of Saudi Arabia, the United Arab Emirates, Qatar, and Bahrain. Israel, Malta, and the Maldives also rely heavily on desalinated water. The United States has more than two thousand desalination plants. The cities of El Paso, which relies on desalination for one-quarter of its water, and Tampa are the major adopters. Barcelona, Sydney, Algiers, and even London are constructing or have recently opened major plants.
Despite such widespread adoption, however, desalination remains a small player at the global level, accounting for less than one percent of total water consumption. Much of this is due to the lower cost of alternative surface and groundwater sources in most places. Desalination is expensive no matter how you do it. Energy and construction costs are high, making the water as much as ten times more expensive than many surface or groundwater supplies. The Saudi Arabian plant at Shoaiba produces a massive 450 million liters a day but cost more than $1 billion to construct.
Desalination also imposes high operating costs. Heating the water or forcing it through filters takes a lot of energy. Most desalination plants rely on coal- or oil-fired power plants, and the greenhouse gases emitted, unfortunately, contribute to climate
change. As a result, there is increasing interest in renewable energy. The desalination plant in Perth, Australia, is partly powered by the Emu Downs Wind Farm. The plant in Sydney offsets its energy use with renewable power from an inland wind farm. Delft University in the Netherlands has a project underway that couples a small desalination plant with an on-site windmill. With the catchy title “Drinking with the Wind,” the combined operation can provide enough water for five hundred families. While wind holds promise as a means to reduce desalination plants’ contribution to climate change, the more common non–fossil fuel energy source is nuclear. India, Japan, Russia, and other countries rely on nuclear power both on the land and at sea to power their desalination plants. A U.S. Navy aircraft carrier uses its nuclear reactor to provide desalinated drinking water to the small city aboard—up to four hundred thousand gallons per day.
Even if the energy source does not generate greenhouse gases, desalination creates a serious waste stream. Ocean water obviously contains a much higher concentration of salt than freshwater. The waste product resulting from desalination, called brine, is even more saline and is produced in large quantities. For every hundred gallons of water treated in a reverse osmosis plant, as much as fifty to eighty-five gallons will be discharged as brine. The Environmental Protection Agency treats brine as a waste regulated under the Clean Water Act. Simply discharging brine into the ocean can cause significant harm to the local marine environment. Because brine is denser than seawater, it tends to sink to the ocean bed, killing filter-feeding animals such as coral and the nonmobile eggs and juveniles of other species at the sea bottom. This is an even greater problem in semi-enclosed areas such as bays and estuaries, where water does not easily mix. As a result, some desalination plants have long pipes that discharge the brine far offshore, often using multiple branches to diffuse the discharge over a larger area.
Despite the high start-up costs, entrepreneurs are entering the desalination market. The strategy of the start-up Water Standard is to rely on desalination plants in retrofitted tankers. These ships, part of the company’s H2Ocean product line, will be moored far enough offshore to avoid the environmental problems from discharging brine but close enough that transporting the freshwater to the shore via pipe or ship is practical. The company envisions producing up to seventy-five million gallons of freshwater a day. Venture capitalists clearly think there is money to be made, and have provided $250 million in funding to get the business going.
Despite its financial and environmental costs, whether powered by fossil fuels, wind, or nuclear power, desalination seems certain to become a more significant source of drinking water in the
coming decades. Given the likelihood of prolonged droughts from climate change, the prospect of turning salt water into clean freshwater cannot help but be an obvious option as cities seek new sources to satisfy their growing populations. Over time, technology will continue to develop and the problems of high energy use and brine discharge may well become less significant. Desalination is not, however, a silver bullet. Because water is expensive to move across land in large quantities, particularly uphill, cities far from the coast or at high elevations will not find the technology helpful because of its high costs. Nor, of course, will poor communities unable to afford the high capital and energy costs. Peter Gleick, the noted water authority, projects that desalinated water will supply no more than 0.3 percent of the United States’ water supply.
As with any market, the future for projects providing large amounts of water, whether tankers or desalination plants, depends, of course, on supply and demand. But there are other factors to consider. How expensive is it to obtain the clean water? How much does it cost to move the water from its origin to the site of consumption? And, critically, what is the city’s marginal cost of supply? This last point is subtle but important. The challenge facing local government is not simply how to get water in times of drought but the most efficient way to do so. Every city has a drinking water supply system in place that provides the bulk of the water consumed. The question is how much an additional gallon of water will cost
on top
of what the system already produces. If the system generally provides enough water and extra supplies are only needed sporadically, then an expensive, temporary strategy such as tankers may be appropriate. While costly on its face, transporting water by tankers or giant bladders is considerably less expensive than installing large pipelines. If, by contrast, a steady shortfall in water supply is likely, then more capital-intensive approaches such as pipelines or even a desalination plant with much higher up-front costs that will take decades to pay off may prove a wiser long-term financial investment.
There is a trade-off between water volume and infrastructure cost. Water from a tanker may feel expensive compared to the normal cost of water but prove far less expensive for three months’ supply
than paying for a permanent desalination plant or miles and miles of pipes to a distant source, not to mention buying rights-of-way through private land. For an additional supply extending two or three decades, though, tankers may prove much more expensive. It all depends on how often the current system will prove inadequate and how much additional water is needed.
The other basic problem faced by water entrepreneurs is that they are not playing on a level field. They know how much it costs per gallon of freshwater to tow an iceberg or sail a tanker but, in the absence of a drought or dire situation where a city will pay almost regardless of the price, they have to match or beat the current cost of water. Unfortunately for them, urban water is not generally subject to market forces. In most cases, both the water and infrastructure are owned by the government. Even when private providers are allowed, the rates are often regulated. The net result is, more times than not, a subsidized good. There are arguments why governments may want to ensure that water is inexpensive, but make no mistake. It provides a strong disincentive for the development of additional sources by entrepreneurs who simply cannot compete on price. Because of this, much of the entrepreneurial energy has focused on emerging technologies for smaller scale supply.
The military is a good place to start. Since the time of the Roman legions and well before, every army on the move has sought to improve its logistical efficiency. Safe drinking water is critical to battle success. Generals from Vegetius to Rommel have emphasized that dangers to troops from dysentery and diarrhea can be as harmful as battlefield casualties. If safe water can be provided locally, all the better, since it avoids the costs of transport. A current initiative under development with the U.S. Department of Defense is capillary condensation. This technology captures the water vapor from burning diesel fuel. Basic chemistry suggests that one could capture one gallon of water from one gallon of diesel fuel burned.
On a smaller scale, the LifeStraw is a simple device intended for individual use to purify drinking water. About a foot long and easily hung from the neck, the plastic casing encloses filter membranes. The only energy needed is from a person who literally sucks
through the straw, drawing water through the pores and filtering out bacteria and parasites. Designed to treat a thousand liters, roughly the amount a person drinks in a year, the LifeStraw costs only two to three dollars. There are reports on the web that U.S. troops use LifeStraws to drink from puddles.
Another new technology known as WaterMill produces drinking water from humidity in the air. The machine uses the dew point to create condensation, which then drips into a holding container. The manufacturer claims that the technology can turn outdoor air into approximately thirteen quarts of drinking water every day. To prevent contamination, the machine uses ultraviolet light to sterilize the water collected. Larger atmospheric water generators, such as the Air Water machine, can produce much greater volumes of water. Following the 2004 tsunami in Thailand and Sri Lanka, thirteen 3.5-ton water generators, each the size of a small trailer, were deployed. These large machines have also been used by the U.S. Marines, Indian border police, and South African military.
