Monday, November 26, 2012

Solar Power When the Sun has Set


(CNN) -- What if we could use solar energy when the sun has set, or wind energy when the air is calm? Donald Sadoway is working on a way to make that happen.
The professor of materials chemistry at MIT is leading an effort to develop a new kind of battery -- a "liquid metal battery" -- that would enable the economical storage of energy from solar, wind and other sources so that it could be used when homes and businesses need it.
Sadoway's work landed him on TIME's list of the world's 100 most influential people this year and last month he was a guest on the Colbert Report.
In March, he described his project in an interview with CNN after giving a talk at the TED conference in Long Beach, California. "We need to have reliable sources of electricity. And wind and solar in harmony with a battery become reliable 24/7," Sadoway said.
Watch Donald Sadoway's TED Talk
Describing his group's work at MIT, he said, "We think it's a breakthrough because it addresses all of the uniquely demanding performance requirements of the grid, namely uncommonly high power, long service lifetime, but in addition, meeting the super-low price point of this application.
Using nature to grow batteries
Sadoway explained the importance of the liquid metal battery in his TED Talk this way:
"The electricity powering the lights in this theater was generated just moments ago. Because the way things stand today, electricity demand must be in constant balance with electricity supply. If in the time that it took me to walk out here on this stage, some tens of megawatts of wind power stopped pouring into the grid, the difference would have to be made up from other generators immediately. But coal plants, nuclear plants can't respond fast enough. A giant battery could.
"With a giant battery, we'd be able to address the problem of intermittency that prevents wind and solar from contributing to the grid in the same way that coal, gas and nuclear do today.
"You see, the battery is the key enabling device here. With it, we could draw electricity from the sun even when the sun doesn't shine. And that changes everything. Because then renewables such as wind and solar come out from the wings, here to center stage."
Using biology to rethink the energy challenge
Inspired by the technique developed in the 19th century to produce aluminum at very low cost, Sadoway came up with the idea of using such commonly available materials as magnesium and antimony to create the battery.
He said a battery of this type housed in a 40-foot shipping container could store enough power to meet the daily needs of 200 American households.
Sadoway got enthusiastic applause when he told the audience at TED: "If we're going to get this country out of its current energy situation, we can't just conserve our way out; we can't just drill our way out; we can't bomb our way out. We're going to do it the old-fashioned American way, we're going to invent our way out, working together."

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