1 July 2011

Fueling the future

From Superman materials to tree-bark gasoline, the MagLab is on the front line of energy research.

By KATHLEEN LAUFENBERG

Spinning straw into gold? Bottling nature's genies? Discovering materials with Superman powers? Sure enough. It's all in a day's work at the Magnet Lab, where scientists seek new sources of green energy as well as novel ways to store it.

"There's a tremendous need for clean energy today," said physicist and Magnet Lab director Greg Boebinger. "But as soon as you start talking about renewable sources like the wind and the sun, the big issue becomes storage.

Illustration by Liz Vernon.Illustration by Liz Vernon.

"When the sun shines, you collect its energy. When the wind blows, you collect its energy. But then you have to find a way to store the energy until you need it days or months later. Many scientists who visit the MagLab are working on that problem."

Analytical chemists, including assistant scholar-scientist Amy McKenna, are also investigating how to conserve oil supplies by manufacturing new liquid fuels. Their goal, simply put, is to spin straw into gold.

"We want to take agricultural waste, stuff that would be thrown away or mulched or composted," McKenna said, "and turn it into fuel."

Other scientists, such as Los Alamos National Laboratory physicist Albert Migliori, want to create an artificial fuel that burns more cleanly than petroleum by using the energy of the sun and wind to run a chemical reaction. If Migliori and others can find a way to bottle these potent genies, the discovery could radically increase our ability to convert nature's own power into something we can use instead of oil.

Physicists and engineers are also on the prowl for Superman materials known as superconductors: metals, alloys and ceramics that allow electricity to flow with no resistance or loss of energy. Finding the right superconducting material could make our current power grid much more efficient. It could even open up energy avenues we haven't yet imagined.

The search for "unobtainium"

In the popular sci-fi movie "Avatar," an Earth company traveled at great expense to an alien planet to mine its "unobtainium." This fictional ore was Hollywood's depiction of the holy grail of superconductors: a material able to conduct staggering amounts of electricity without resistance and energy loss. That's not the case with today's national power grid.

"We waste 10 percent of our power heating up the power lines," Boebinger said. "If we could find a way to transmit electrical energy without doing that, we would realize a huge savings."

Our country's energy grid operates much like your kitchen toaster. Both have wires that heat up as electricity flows through them. Electrons cause the heat as they zoom through the wires, bumping into other electrons and atoms. These atomic collisions cause friction, and that friction generates heat. In your toaster, the red-hot wires nicely brown your bread. In our energy grid, the wires' heat just toasts the air and is wasted.

But that's not how superconducting wires work. In superconductors, the electrons flow without collisions. Scientists already use superconducting materials to transmit energy — but there's one big catch. In order for them to work, today's superconductors must be kept super cold, as in minus 347 degrees Fahrenheit and even colder! To keep superconductors that cold, they're bathed in liquid helium, the coldest liquid on earth. It's a complicated, costly process that takes up a huge amount of space.

So MagLab researchers keep looking for a superconductor that won't need to be kept so crazy cold. Their ultimate goal: Find a room-temperature superconductor — just like the "unobtainium" in Avatar. It would be a revolutionary discovery, worthy of a Nobel Prize.

"It's impossible to predict when that might happen," Boebinger allowed. "But I don't see why it couldn't happen someday. In the meantime, there are plenty of technological breakthroughs that we can predict using materials that are already discovered."

There's a tremendous need for clean energy today. But as soon as you start talking about renewable sources like the wind and the sun, the big issue becomes storage.

A case of sun to go, please

While material scientists are hunting for "unobtainium," other researchers are experimenting with ways to capture the immense energy of the wind and sun.

With petroleum and coal, storage isn't much of a problem. A lump of coal sits ready for you to burn it. The gas in your car waits for you to turn the key.

"Liquid fuels are an incredibly efficient, cost-effective way to store energy," Boebinger said. "Ultimately, the challenge is to try to find an inexpensive energy alternative to petroleum."

Why is petroleum such a terrific fuel? Because it holds more energy than anything except nuclear power.

"There are 100,000 different molecules in one drop of oil, and there are hundreds of thousands of different molecules in petroleum," he said. "Basically, nature has made every possible organic compound in oil, and at some level, it's really a shame we burn the stuff because it's the most complete collection of molecules that we have. But right now, all we know how to do is set a match to it and harness the energy."

The sun is also an incredible source of energy — but storing it is a problem.

"We know how to make electricity from sunlight, and we know how to make electricity from wind, but we don't have the technology to store anywhere near what we need to match our energy usage in the United States from these clean energy sources."

Physicist Migliori is spearheading a group of researchers at LANL, Florida State University and the University of Florida to brainstorm ways to do that. He wants to make synthetic liquid fuel from sunlight and wind that can be used in fuel cells — devices that change chemicals into electricity without pollution. Fuel cells contain different materials than batteries and are designed to never wear out or go dead.

"The technology to change electrical-energy storage," Migliori said, "is on the horizon."

Unlike today's fuel cells, however, the ones Migliori envisions will not use hydrogen — a dangerous gas that's hard to store. Instead, they will use an artificial gasoline. To develop a process to make such a synthetic fuel, he and others are using the lab's powerful magnets to study the physics and chemistry at the interface between solids and liquids.

Trash or treasure?

If you understand the molecular nature of something, you can begin to predict how it will behave …

In McKenna's and graduate-research student Jackie Jarvis's lab, it's all about transformation. In order to make our petroleum reserves go as far as possible, they want to morph tree waste and peanut shells into biofuels.

Fuels made from food, such as the ethanol in your car's gasoline, are called first-generation biofuels. Non-food fuels, such as tree waste and peanut hulls, are second-generation biofuels. The MagLab hopes to help create a fuel mixture that's 85- to 90-percent gasoline and 10- to 15-percent second-generation biofuel.

Jarvis gets her research samples from forestry services. After they burn scrap tree bark, branch pieces and leaves, they send samples of the gooey remains in glass vials to Jarvis. The syrupy samples have a strong burnt odor, so the smell of smoldering fire often wafts through her tidy lab.

To test a sample, Jarvis puts a smidgeon of the burnt goo inside a giant ion-cyclotron resonance magnet. The machine gives her a molecule-by-molecule readout of what's in it. Such an analysis conveys how well the sample could blend with petroleum. Before using the Ion Cyclotron Resonance (ICR) machine, researchers could identify only about 300 compounds. Now, Jarvis said, she has identified as many as 20,000 compounds in one tiny sample.

"If you understand the molecular nature of something, you can begin to predict how it will behave in the refinery," McKenna said. "That's important, because refinery systems were built for petroleum, but now we've got this different product we want to put in them."

Many of the biofuel samples contain a lot of oxygen, she added, which will corrode the refinery's machinery. The lab's goal is to find an agricultural waste that could be added to petroleum in the beginning stage of the refining process. Something that wouldn't be too destructive to the refinery equipment — or, later, in your car's engine.

So far, the perfect biofuel has remained just beyond their grasp. But that's part of the challenge of spinning straw into gold.


This story was originally published in Issue 7 of flux magazine, a discontinued publication of the National High Magnetic Field Laboratory.