Because of the quick economic development after world war 2, water supply problem became more and more serious. And the seawater desalination come to life with different technology, reverse osmosis (RO), forward osmosis (FO), electrodialysis (ED), multistage flash (MSF), multieffect distillation (MED), multistage flash evaporation(MSF) membrane distillation (MD) and ion exchange (IX). And now according to related statistics, reverse osmosis (RO) takes 60% market share and multistage flash evaporation(MSF) occupies 26.8% market share of the total world seawater desalination plants.
According to the international desalination association (IDA), by 2013, there are more than 17,000 global desalination plants, distributed in some 150 countries. Some or all of the more than 300 million people rely on desalination to meet daily need
With the efforts to save the cost of using, the performance of US companies is more eye-catching. In 2008, the US Forbes website disclosed that a company in San Antonio, California to dilute the cost of seawater desalination to USD0.46 / ton. However, the rise in energy prices has also pushed up the cost of desalination. The United States, “Wall Street Journal” in 2007, said the United States Poseidon Resources was approved in California, San Diego, Carlsbad, built a 190,000 tons / day of desalination plant, the initial cost estimates are very optimistic Ton less than $ 0.4, but in 2012 re-assessment, has doubled to 0.81 US dollars per ton.
We all know that the development of solar photovoltaic industry, although the technological progress makes the cost greatly reduced, but the government’s subsidy policy on the development of this industry has played a significant role in the German market. Due to government subsidies, people have enthusiasm to install the photovoltaic power generation system and to make money by selling the remaining PV power to the country at a higher electricity price. This policy has helped to promote the photovoltaic power generation system widely used and helped to protect a better environment.
Although the rapid development of desalination technology brings significant reduction in the cost of use, the cost of desalination cannot compete with freshwater tap water plants. With regard to the model of photovoltaic power generation systems, if the government is able to introduce appropriate subsidy policies to encourage the use of desalination systems in areas where freshwater is relatively scarce, it will be conducive to the popularity of desalination systems and the involvement of relevant enterprises. And avoid our excessive use of groundwater, better protect our planet’s ecology.