Of the estimated 22 million cubic meters of freshwater being produced a day through desalination processes worldwide, less than 1% is made using solar energy. Because of inexpensive methods of freshwater delivery and abundant low cost energy resources, solar distillation has, up to this point, been viewed as cost prohibitive and impractical.
According to the International Renewable Energy Agency (IRENA), desalination with renewable energy can already compete cost-wise with conventional systems in remote regions where the cost of energy transmission is high. Elsewhere, it is still generally more expensive than desalination plants using fossil fuels, but IRENA states that it is ‘expected to become economically attractive as the costs of renewable technologies continue to decline and the prices of fossil fuels continue to increase.’
Solar water disinfection is a type of portable water purification that uses solar energy to make biologically-contaminated (e.g. bacteria, viruses, protozoa and worms) water safe to drink. Water contaminated with non-biological agents such as toxic chemicals or heavy metals require additional steps to make the water safe to drink.
CASE STUDY 1
In the Galapagos a company is looking to take reject water of a desalination plant and refine that water into fresh water and its by product would be a small voguish salt business. The result is of course no reject water back into the Galapagos.
CASE STUDY 2
Saudi Arabia meets much of its drinking water needs by removing salt and other minerals from seawater. Now the country plans to use one of its most abundant resources to counter its fresh-water shortage: sunshine. Saudi Arabia’s national research agency, King Abdulaziz City for Science and Technology (KACST), is building what will be the world’s largest solar-powered desalination plant in the city of Al-Khafji.
The plant will use a new kind of concentrated solar photovoltaic (PV) technology and new water-filtration technology, which KACST developed with IBM. When completed at the end of 2012, the plant will produce 30,000 cubic meters of desalinated water per day to meet the needs of 100,000 people.