As concerns about water supply continue, more and more stories seem to point to desalination as the answer. Until now, most Texas desal plants are small and regionally located, but a seawater desalination plant will open on South Padre Island in 2014 again opening conversations about importing water from the coast to Central Texas. El Paso is the largest municipal user of desal technology in Texas. The plant on Fort Bliss is capable of treating 27.5 million gallons of water a day for regional users. Like other technologies, desalination can be a useful tool for water resources, but there are other important considerations to be made before it is hailed as the final solution.
To date, one of the stopping points for using desal as a water supply alternative is it's price. Treatment of brackish groundwater can be 4 times as expensive as freshwater supply and the price increases considerably for salt water. Of course price is also contingent on location. Brackish groundwater often has the advantage of being local without additional pipeline costs, whereas some discussed projects such as hauling treated Gulf water instate would have exponential costs added for pipeline construction and transport. Property owners along the way might also wonder where that pipeline is going to be located and through what legal means will it be placed there.
As we have mentioned here before, it takes energy to move and treat water. This needs to be considered for these larger projects. A city can increase its water sustainability while inadvertently decreasing energy sustainability. Proposals for these projects need to include calculations of the associated energy footprint so that the big picture is considered. Energy needs also increase based on the salinity of the water because additional treatment is required. Long-haul projects also require large amounts of energy. To bring water from the coast to San Antonio, 140 miles of pipelines would need to be installed with large amounts of power to push the water uphill.
The key to desalination is to see it is as a part of a suite of solutions like El Paso has. The city employed the new technology along with a host of other conservation, efficiency and water supply projects. Because of the pricing and energy drawbacks of desalination, other supply options such as water efficiency programs should be fully implemented before additional treatment plants are built. Regional brackish water treatment makes more sense, where possible, than piping treated water long distances. Technology can provide some great solutions, but it is not a magic cure. It must be paired with common sense and evaluated with all the data to ensure a well rounded sustainable system.