USAID recently announced the winners of the Desal Prize, part of a competition to see who could create an affordable desalination solution for developing countries. The idea was to create a system that could remove salt from water and meet three criteria: it had to be cost-effective, environmentally sustainable, and energy efficient.
The winners of the $125,000 first prize were a group from MIT and Jain Irrigation Systems. The group came up with a method that uses solar panels to charge a bank of batteries. The batteries then power a system that removes salt from the water through electrodialysis. On the most basic level, that means that dissolved salt particles, which have a slight electric charge, are drawn out of the water when a small electrical current is applied. In addition to getting rid of salt (which makes water unusable for crops and for drinking), the team also applied UV light to disinfect some of the water as it passed through the system.
Using the sun instead of fossil fuels to power a desalination plant isn't a totally new idea. Larger solar desalination plants are being seriously investigated in areas where water is becoming a scarce resource, including Chile and California. While proponents hope to eventually could provide water to large numbers of people, the technology is still expensive (though prices are dropping) and requires a lot of intricate technology.
The engineers at Ubiquitous Energy are developing solar panels that are completely transparent and as thin as a laminate. They can do this by creating see-through solar cells that absorb only the invisible parts of the solar spectrum—ultraviolet and infrared radiation.
With its wings stretched wide to catch the sun's energy, a Swiss-made solar-powered aircraft took off from Abu Dhabi just after daybreak Monday in a historic first attempt to fly around the world without a drop of fossil fuel.
Solar Impulse founder André Borschberg was at the controls of the single-seat aircraft when it lumbered into the air at the Al Bateen Executive Airport. Borschberg will trade off piloting with Solar Impulse co-founder Bertrand Piccard during layovers on a 35,000-kilometer (21,700-mile) journey.
Some legs of the trip, such as over the Pacific and Atlantic oceans, will mean five days and five nights of flying solo. Both pilots have been training hard for this journey, which will span 25 flight days over five months before this Spruce Goose of renewable energy returns to Abu Dhabi in late July or August.
"It is also exciting because you know, you simulate, you calculate, you imagine, but there is nothing like testing and doing it in real," Borschberg said just hours before takeoff. "I am sure we are all confident and hopefully we will be able to see each other here in five months."
The Solar Impulse 2 aircraft, a larger version of a single-seat prototype that first flew five years ago, has a wingspan of 72 meters (236 feet), larger than that of the Boeing 747. Built into the wings are 17,248 ultra-efficient solar cells that transfer solar energy to four electrical motors that power the plane's propellers. The solar cells also recharge four lithium polymer batteries.
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