Off-Grid power, water tech breakthrough

Prof Jerry Woodall

Researchers at Purdue University have developed an aluminum alloy that could be used in a new type of mobile technology to convert polluted water into drinkable, while extracting hydrogen to generate electricity.

The potable water could be produced for about $1 per gallon, and electricity could be generated for about 35 cents per kilowatt hour of energy, which is low compared to the cost of solar at 10 times that amount.

It might be used to provide power and drinking water to remote villages or for military operations, said Jerry Woodall,  Professor of electrical and computer engineering.

The alloy contains aluminum, gallium, indium and tin. Immersing the alloy in freshwater or saltwater causes a spontaneous reaction, splitting the water into hydrogen and oxygen molecules. The hydrogen could then be fed to a fuel cell to generate electricity, producing water in the form of steam as a byproduct, he said.

“The steam would kill any bacteria contained in the water, and then it would condense to purified water,” Woodall said. “So, you are converting undrinkable water to drinking water.”

Because the technology works with saltwater, it might have marine applications, such as powering boats and robotic underwater vehicles. The technology also might be used to desalinate water, said Woodall, who is working with doctoral student Go Choi.

A patent on the design is pending.

Woodall envisions a new portable technology for regions that aren’t connected to a power grid, such as villages in Africa and other remote areas.

“There is a big need for this sort of technology in places lacking connectivity to a power grid and where potable water is in short supply,” he said. “Because aluminum is a low-cost, non-hazardous metal that is the third-most abundant metal on Earth, this technology promises to enable a global-scale potable water and power technology, especially for off-grid and remote locations.”

“There is no other technology to compare it against, economically, but it’s obvious that 34 cents per kilowatt hour is cheap compared to building a power plant and installing power lines, especially in remote areas,” Woodall said.

The unit, including the alloy, the reactor and fuel cell might weigh less than 100 pounds.


5 Responses

  1. This is a truly amazing and world transforming technology. The main obstacle I see in the creation and commercial distribution of this is our current economic model. Capitalism thrives on scarcity. This invention, if properly implemented and further expanded, has the potential to create massive abundance in developing countries. Guess who that is bad for? Developed countries whose economic model thrives on scarcity. A need is created, i.e. potable water and electricity, and a corporation will service that need. You can’t just give someone a product that infinitely eliminates that need in the future. That’s corporate suicide. This is an amazing invention with lots of promise but, sadly, it won’t thrive until our post free-market society.

  2. water purification through electrolysis, i had the same idea some time ago when i was first started researching hydrogen generators and such.. the problem i see is if you do turn the hydrogen and oxygen back in to stem, do you not need to add minerals back into he water…if you take everything out of water then there will be nothing your body can use.?

  3. For a given area of Alloy, what would be the of gassing rate (lpm) of hyrdogen? Is the rreaction driven chemically or is this an electrolysis driven reaction and if so what are your applied voltages and current requirements for a given lpm of hydrogen?

  4. From the article: “..and electricity could be generated for about 35 cents per kilowatt hour of energy, which is low compared to the cost of solar at 10 times that amount.” !!!

    I have no idea where this figure came from, but it’s way off the mark. The highest figure I’ve seen for life-of-installation, off-grid per kwh cost is around $.75, an outdated study. PV prices have dropped dramatically since. A 2009 Scientific American article/study (behind paywall) found that the cost of off-grid PV electricity fell between 40 and 70 cents / kwh over 20 years. I’ve seen lifetime estimates below $0.30, depending on system configuration, location, etc.

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