Beth Kelly is a freelance science writer with a strong interest in nuclear power and its potential as a clean energy source. A graduate of DePaul University, she is currently based out of Chicago, Ill. Find her on Twitter at @bkelly_88.
Nuclear Desalination: Technology for a Thirsty Planet
As the world's population booms, its resources struggle to keep pace. Water scarcity is one of the most important issues to be confronted by global communities in the years ahead-already an increasingly vast number of regions worldwide face chronic water shortages, and with demand projected to grow an additional 40 percent by 2050, the threat of violence over access to clean drinking water is both a real and urgent one. With shifting climate patterns further exacerbating the problem, investing in economically-efficient and sustainable water utilization tactics immediately is crucial.
Accelerated urban development and agricultural intensification has brought social and economic benefits, but our ecosystems have paid the price. Groundwater systems that constitute the predominant reserves of freshwater on Earth are threatened by contaminants and pollution, the effects of hydraulic fracking, and a lack of effective management strategies. Many of the world's aquifers face degradation and imminent depletion. While better water conservation and pollutant monitoring can help control the issue, now sources of freshwater-such as seawater desalination-will also assist in alleviating current and projected water stress.
Based on current statistics, only 1 percent of the global population receives water from desalination. However, the United Nations expects 14 percent of the global population to receive water from desalination by 2025. The desalination of water has been practiced for years, but until recent years high economic and energy costs have made it a largely prohibitive solution. Now, with new technological advances and greater freshwater scarcity fueling demand, it's likely that the process of nuclear desalination will play an increasingly important role coming into the future.
On paper, desalination sounds straightforward-essentially there are two main methods through which the process is completed. In a membrane desalination process, saltwater is pumped through pipes and then through specially designed membranes that allow the water molecules to pass through but trap the bigger salt molecules. There are several kinds of membrane desalination processes with the most common type using reverse osmosis to filter out the salt. In a thermal process, the saltwater is boiled and the vapor condenses as freshwater.
Unfortunately, the desalination process is not necessarily a "clean" one. According to Direct Energy, it is still almost always cheaper to use local freshwater than to desalinate seawater. And desalination, as with nearly all industrial processes, typically sources its energy from dirty carbon-based resources. Nuclear power therefore offers an appealing solution-in terms of availability and reliability it is competitive with fossil fuels, and meets all the essential requirements in order to feed a desalination plant. Because nuclear energy seawater desalination creates minimal environmental pollution and greenhouse gas emissions, it holds tremendous potential for the future production of freshwater.
Today, California is in the midst of a persistent, worsening drought. Groundwater is a vital resource in a time of drought, but it takes decades or even centuries for the aquifer to replenish itself. People in California have usually depended on groundwater for 40 percent of their water supply; since the drought, however, that number has jumped to over 60 percent. The state of California has already implemented conservation measures, but with the aquifers depleted and groundwater disappearing, the land itself has begun to collapse. A NASA scientist says in a report released Wednesday, Aug. 19, 2015, that parts of California's Central Valley are sinking faster than ever as groundwater is removed at unprecedented and unsustainable rates.
The only power facility in California that is not dependent upon the state's precious water resources is the Diablo Canyon Nuclear Power Plant in San Luis Obispo County. Desalinating ocean water using reverse osmosis and ultrafiltration, the plant sells back fresh water to the local community. Paying $3.34 for every thousand gallons, their rates are comparable to what the San Diego County currently pays for water.
Many other countries worldwide-South Korea, Pakistan, Japan, China, and Argentina-also have nuclear power plants that desalinate seawater. In Russia, the only large nuclear facility with a water desalination facility was located in Aktau in the former Soviet Union, now Kazakhstan. At one time it delivered over 100,000 cubic metres of fresh water per day, but it was shut down in April 1999 and is now being decommissioned. More recently, however, the country announced its plans to work with foreign partners to both finance and construct a new nuclear plant with a desalination facility. The new plant hopes to provide 170,000 cubic metres of fresh water a day from one nuclear power unit.
Nuclear desalination is not a new technology, and desalination methods date back millennia. Furthermore, the need for water and sources of water is only going to increase. We need desalination plants that don't run on fossil fuels, and nuclear desalination plants fit the bill perfectly.