Can Sun and Wind Make More Salt Water Drinkable?
June 22, 2015
But one thing hasn't changed since the time of the ancient mariners: It takes a lot of energy to squeeze drinkable water from salt water. So even though more than 70 percent of the Earth's surface is covered with water, civilization has quenched its thirst mainly by tapping the one percent of world water that is unfrozen and fresh.
The one notable exception: Oil-rich Saudi Arabia and neighboring arid nations have used their wealth to purify ocean water. Yet their water demand is rising with population growth and industrialization at the same time that climate change is shrinking supply. Oil states, which depend on selling crude overseas for revenue, are loath to burn more barrels to keep drinking water flowing at home. So some aim to fuel new desalination operations with another abundant resource—the sun.
Other water-starved regions around the world want to do the same.
"Desalination is energy-intensive, but it doesn't have to be fuel-intensive," said Aaron Mandell, co-founder and chair of WaterFX, one of the companies pioneering the renewables approach. "That's what really matters. The focus should be not so much on consumption, but where the energy comes from."
Here are four places trying to tap the sea and brackish underground water supplies with the help of solar and wind energy:
The Middle East
In the United Arab Emirates (UAE), construction begins in the coming weeks on four small pilot desalination plants. But the world's sixth largest oil producer (second in the Middle East only to Saudi Arabia) is not rushing into the solar part of the equation. Instead, UAE energy company Masdar plans to test four companies' different technologies to determine which is most energy-efficient.
By mid-2016, Masdar will select a system to couple with solar power, a decision sure to be closely watched by its neighbors. Fresh water available per citizen in the Middle East is just one-seventh the world average, and scarcity is growing. Climate change could shrink rainfall and fresh water availability by 40 percent by 2050, says the World Bank.
The bank has urged the region to take advantage of its enormous solar energy potential—several orders of magnitude larger than current total world electricity demand. Solar radiation per square kilometer in the region each year is equivalent to the energy generated by one to two million barrels of oil.
Source: news.nationalgeographic.com
