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Highways basking in the hot sun are wasted energy. Scott Brusaw's solution? Make them out of solar panels

Each 12-by-12-foot Solar Roadway panel would produce about 7,600 watt-hours a day, based on an average of four hours of sunlight. At that rate, a one-mile stretch of four-lane highway could power about 500 homes. “If we could ever replace all the roads in the U.S., then, yeah, we would produce more electricity than we use as a nation,” says Brusaw, an electrical engineer who completed his first prototype panel in February with funding from the U.S. Department of Transportation.

Brusaw’s goal is to get the cost per panel under $10,000. That’s roughly three times the cost of asphalt. But he wants to make panels that last three times longer than asphalt roads, which have to be resurfaced every 10 years in many places. “Then the cost is about the same,” he says. “But that’s just a break-even. We’re also generating electricity.”

The key to commercial viability will be the panels’ glass. It must be textured for traction, embedded with heating elements for melting away ice and snow, and able to survive years of traffic. “The toughest is going to be that fast lane on the highway,” Brusaw says, “where you’ve got a 40-ton truck, maybe with snow chains. It will have to be able to withstand all that.” At the same time, it has to be self-cleaning if sunlight is to reach the PV cells; Brusaw points to experimental hydrophilic glass that uses sunlight to break down organic dirt, and rainwater to wash it away without streaking.

Next up for Solar Roadways will be qualifying for Phase II funding, a two-year, $750,000 deal to develop a commercial plan for the panels. At the end of those two years, Brusaw would like to be ready for testing in parking lots, which he sees as the perfect proving grounds for the lights and the power-generation system. Directional arrows and parking lines could be reconfigured to deal with busy times, and the electricity generated could feed adjacent businesses. “I talked to the guy in charge of power for Wal-Mart,” Brusaw says. “Superstores are roughly 200,000 square feet, and parking lots are about four times that. I crunched the numbers for an 800,000-square-foot lot and told him how much power it could generate even if it was completely full of cars. It was 10 times the power they use.”

Brusaw wants to start smaller, though—on the scale of, say, a fast-food restaurant. A McDonald’s retrofitted with a solar parking lot could take itself largely or entirely off the grid or become a site for recharging electric vehicles (while the owners stopped inside for food, naturally). “Even the best electric cars have a range of about three hours,” he explains. “But if all I have to do is find a McDonald’s, I could drive from Idaho to the southern tip of Florida.” Improbable? Yes. But “Billions of watts served” would be a cool new tagline.

Josh Dorfman is the author of The Lazy Environmentalist: Your Guide to Easy, Stylish Green Living

Willem van Cotthem’s super-soil harnesses the power of Pampers to turn dirt into lush gardens

The secret is hydrogels, powerfully absorbent polymers that can suck up hundreds of times their weight in water.

Hydrogels have many applications today, from food processing to mopping up oil spills, but they are most familiar as the magic ingredient in disposable diapers. The difference with agricultural hydrogels is that they don’t just trap moisture; they let it go again, very slowly, almost like time-release medication, into the root system of plants. That continuity of moisture is what brittle landscapes like deserts need to become fertile again. Water activates a mineralization process, setting free nutrients in the soil so that life can grow.

But water alone won’t make gardens flourish in sand. So van Cotthem, an honorary professor of botany at Ghent University in Belgium who has helmed several international scientific panels studying desertification, invented a “soil conditioner” called Terracottem. It’s an 8- to 12-inch layer of dirt impregnated with hydrogels, along with organic agents that nourish the natural bacteria in the soil.

Van Cotthem’s early experiments with his soil are now literally bearing fruit on every continent except Antarctica. Where Terracottem sits, barren plots of land are now fertile, and have already changed lives. In 2005, UNICEF invited van Cotthem to oversee the construction of “family gardens” in the Sahawari refugee camps in Algeria. Since 1975, thousands of Africans in the camps have lived in tents and shacks, dependent on the World Food Program to provide them with dry and canned goods—a diet that left them vulnerable to disease. Today more than 2,000 pocket gardens there provide healthy food.

If this technology is so miraculous, you might wonder, why wasn’t it developed earlier? After all, disposable diapers have been around since the 1940s. Until only recently, though, hydrogels were toxic, and skeptics doubted that they could ever be made safe for consumption. There was no bigger skeptic than van Cotthem himself—so much so that the day a research engineer from a German diaper company walked into his lab and told him he’d cracked the nut, van Cotthem said to his face, “I don’t believe you.”

“OK,” the engineer said. And he took out a spoon and ate the hydrogel. Van Cotthem was shocked. Then he said to his visitor, “Please come back in a couple of months so that I know you’re still alive.” Meanwhile, van Cotthem tested the samples, got promising results, and began researching the agricultural uses of hundreds of kinds of hydrogels. When the engineer returned alive, van Cotthem was convinced.

But new soil isn’t enough—people still need something to grow in it. Realizing that half the world routinely throws out seeds that the other half needs, van Cotthem also launched a nonprofit organization called Seeds for Food that asks people to mail in their unwanted seeds. “My office right now is full of pumpkin seeds people sent in after Halloween,” he says.

Scientists are exploring different uses for hydrogels. Enhanced soils, they believe, could be the key to farms in space. The recipe is simple: a few drops of water and glass-like marbles to provide a kind of scaffolding for roots in the soil. “Suddenly,” van Cotthem explains, “you have a rich soil that can support almost anything.” But his sights are set firmly on this star system. “I do see the possibility of achieving wonderful things in space,” he says. “But let us first solve the problems here on Earth, starting with offering everyone the chance to produce their own food. And we are certainly in a position to do so.”

David Keith believes strong-arm strategies could soon be our last resort for reversing record levels of carbon in the atmosphere

“If we do the job we should be doing on cutting emissions, and we are lucky, we won’t need geoengineering,” says Keith, a professor at the University of Calgary whose start-up company, Carbon Engineering, is developing commercial-scale devices to capture atmospheric carbon dioxide. That’s the slow and methodical. “But if we can’t control atmospheric CO2 well enough, then we might want to do the solar stuff.” That’s the gunfight.

For several years now, Keith, who has served as a member of Canada’s blue-ribbon panel on sustainable energy technology and as a member of U.S. National Academy of Sciences committees, has been the leading voice in the call for serious research into geoengineered schemes for cooling the planet. The most common example would be to scatter sulfates in the stratosphere to reflect sunlight away from the planet.

The cooling would be immediate and global. We know this, Keith says, because it’s happened before. When Mt. Pinatubo erupted in the Philippines in 1991, the resulting plume of sulfuric ash cooled the planet by about 1°F for a year. Carbon dioxide remains in the atmosphere for centuries, and even the most optimistic proposals for CO2 sequestration would take decades to have an effect. Should we find ourselves faced with an immediate environmental emergency—a shifting Gulf Stream or an impending collapse of the Arctic ice sheets—effective “sunlight mediation” could theoretically be a quick retreat from the edge.

The immediate problems with this, however, are twofold. First, there’s an obvious moral hurdle. Most people reflexively reject notions of geoengineering for fear that they may cause more harm than good, and undermine efforts to reduce carbon emissions. The other drawback is that the method would be cheap and easy enough that even a rogue nation could pull it off, which leaves open the very real possibility of unilateral action with global consequences.

The real hope is to refine geoengineering methods and develop standards while simultaneously working toward a future in which they would never have to be used. That’s where Keith’s carbon-sequestration technology comes in. Most carbon-capture systems propose sequestering CO2 from large facilities such as power plants. Keith’s plan, however, is more mobile, calling for towers that could be deployed wherever in the world land, climate, and labor costs are optimal.

These carbon suckers would employ fans to move air through a solution of sodium hydroxide, which absorbs the CO2. Inside, lime bonds with the carbon dioxide to form solid calcium carbonate. The reaction releases the sodium hydroxide for reuse in the first step, while the CO2 could be stored in underground reservoirs that once housed oil and gas or be recycled into gasoline.

Keith has proven this process with a test tower 20 feet tall and four feet wide that can capture two tons of CO2 per square foot annually (roughly equivalent to the yearly output of one American) using less than 100 kilowatt-hours of electricity per ton. His company expects to spend about $5 million over the next three years refining the technology and investigating how best to scale it up—way up. The ultimate goal is for fields of towers some 300 feet long and 60 feet tall, scrubbing up to 1.1 million tons of carbon a year.

Keith admits that his carbon scrubber is no silver bullet. “We have patents and new ideas,” he says, “but the thing you have to get right is cutting emissions. Unless you do that, CO2 removal will be irrelevant.” And if we don’t do it quickly enough, the guns may have to come out.

The centerpiece is a photovoltaic umbrella dome that collects roughly 90 percent of the house’s energy needs. Made of a common plastic, the pillowy dome traps heat like a greenhouse. That hot air warms water in a tank tucked under the roof, turning out a daily average of 80 bath-ready gallons, even on the darkest days of December. At the umbrella’s apex, a generator-equipped turbine produces electricity and, in chilly months, drives heat into the house. Photovoltaic cells studding the 484-square-foot dome floor create additional electricity.

Generating an estimated average of 33 kilowatt-hours per day, the house can power itself and charge a Tesla Roadster. And the building, submitted for a carbon-neutral housing competition, manages to stay comfortable year-round without air conditioning. The roof is covered in plants under the dome. Walls made of structural board stabilize temperatures. Windows circumscribed by a big dot—the “one” side of the die—absorb light from the sun-drenched south. And the compact footprint means less space to heat and cool.

The five-pound rock in question was discovered in 1984 in the Transantarctic Mountains and is known as the Allan Hills Meteorite, or ALH84001 in astrobiology circles. Many scientists considered the gray-green meteorite a dead end, but the NASA team never stopped studying it and, thanks to improved microscopy techniques, the case for life on Mars is stronger than ever. “You can almost feel the tide turning,” Thomas-Keprta says. “People are looking at our research again.”

The first time around, critics argued that the markings that resembled Earthly bacteria were too small to have been alive (bacteria of the same size have since been found here) and that the organic material in the rock formed in Antarctica. But the killing blow came in 2003. Thomas-Keprta’s group had asserted that magnetite crystals, structures that Earthly microorganisms make, were formed in the meteorite by Martian bacteria. In 2003, however, researchers ran computer models that indicated that geological processes occurring at temperatures too hot to sustain life could have created these magnetites.

Now science is again considering the possibility that ALH84001 is full of fossilized nano-ETs. In Thomas-Keprta’s new magnetite study, she used a focused ion beam to isolate a fraction of the magnetite. When she analyzed the sample’s chemical composition, she found that the magnetites were similar to those created by Earth microbes, and that their specific atomic makeup could not have formed at the high temperatures suggested by critics. “This doesn’t definitively show that the magnetites in ALH84001 are biological in origin,” says Dennis Bazylinski, a bacteriologist at the University of Nevada who refereed Thomas-Keprta’s paper. “But it does show that the thermal mechanism popular among those who think strongly that the magnetites do not have a biological origin is extremely unlikely. I think Kathie really put a nail in the coffin for that explanation.”

Convincing doubters that this means Mars was teeming with life, however, will be difficult. “ALH84001 is a really nice rock, full of lots of cool stuff about early Mars, but nothing in it points in the direction of life,” says David Blake, a NASA exobiologist who studied ALH84001 in the 1990s. “To look at a rock 140 million miles from where it formed and turn it into a whole world is tough.”

Recent studies by other groups of two other Martian meteorites, the Nakhla meteorite, found in Egypt, and Yamato 593, another Antarctic specimen, have yielded features similar to ALH84001. Later this summer, Thomas-Keprta will turn her ion beam on these rocks—which formed in a wet Martian environment ripe for microbes—in hopes of revealing whether it contains biological by-products, and possibly uncovering fossilized cell walls.

Even if ALH84001 really is the dead end some argue, the work has been worth it. Astrobiologists now know how incredibly difficult it is to discern biological agents from geological processes, saving researchers from a wicked learning curve when they someday get a bit of Mars itself on the table. In the next decade, the first sample return missions will bring back a pound of Martian soil, and unless it’s full of living microbes or space maggots, scientists will inspect it with the same methods developed for these meteorites. In the meantime, there are more than 200 pounds of Martian material on Earth. That’s a lot of rocks to practice on.

The five-pound rock in question was discovered in 1984 in the Transantarctic Mountains and is known as the Allan Hills Meteorite, or ALH84001 in astrobiology circles. Many scientists considered the gray-green meteorite a dead end, but the NASA team never stopped studying it and, thanks to improved microscopy techniques, the case for life on Mars is stronger than ever. “You can almost feel the tide turning,” Thomas-Keprta says. “People are looking at our research again.”

The first time around, critics argued that the markings that resembled Earthly bacteria were too small to have been alive (bacteria of the same size have since been found here) and that the organic material in the rock formed in Antarctica. But the killing blow came in 2003. Thomas-Keprta’s group had asserted that magnetite crystals, structures that Earthly microorganisms make, were formed in the meteorite by Martian bacteria. In 2003, however, researchers ran computer models that indicated that geological processes occurring at temperatures too hot to sustain life could have created these magnetites.

Now science is again considering the possibility that ALH84001 is full of fossilized nano-ETs. In Thomas-Keprta’s new magnetite study, she used a focused ion beam to isolate a fraction of the magnetite. When she analyzed the sample’s chemical composition, she found that the magnetites were similar to those created by Earth microbes, and that their specific atomic makeup could not have formed at the high temperatures suggested by critics. “This doesn’t definitively show that the magnetites in ALH84001 are biological in origin,” says Dennis Bazylinski, a bacteriologist at the University of Nevada who refereed Thomas-Keprta’s paper. “But it does show that the thermal mechanism popular among those who think strongly that the magnetites do not have a biological origin is extremely unlikely. I think Kathie really put a nail in the coffin for that explanation.”

Convincing doubters that this means Mars was teeming with life, however, will be difficult. “ALH84001 is a really nice rock, full of lots of cool stuff about early Mars, but nothing in it points in the direction of life,” says David Blake, a NASA exobiologist who studied ALH84001 in the 1990s. “To look at a rock 140 million miles from where it formed and turn it into a whole world is tough.”

Recent studies by other groups of two other Martian meteorites, the Nakhla meteorite, found in Egypt, and Yamato 593, another Antarctic specimen, have yielded features similar to ALH84001. Later this summer, Thomas-Keprta will turn her ion beam on these rocks—which formed in a wet Martian environment ripe for microbes—in hopes of revealing whether it contains biological by-products, and possibly uncovering fossilized cell walls.

Even if ALH84001 really is the dead end some argue, the work has been worth it. Astrobiologists now know how incredibly difficult it is to discern biological agents from geological processes, saving researchers from a wicked learning curve when they someday get a bit of Mars itself on the table. In the next decade, the first sample return missions will bring back a pound of Martian soil, and unless it’s full of living microbes or space maggots, scientists will inspect it with the same methods developed for these meteorites. In the meantime, there are more than 200 pounds of Martian material on Earth. That’s a lot of rocks to practice on.

The five-pound rock in question was discovered in 1984 in the Transantarctic Mountains and is known as the Allan Hills Meteorite, or ALH84001 in astrobiology circles. Many scientists considered the gray-green meteorite a dead end, but the NASA team never stopped studying it and, thanks to improved microscopy techniques, the case for life on Mars is stronger than ever. “You can almost feel the tide turning,” Thomas-Keprta says. “People are looking at our research again.”

The first time around, critics argued that the markings that resembled Earthly bacteria were too small to have been alive (bacteria of the same size have since been found here) and that the organic material in the rock formed in Antarctica. But the killing blow came in 2003. Thomas-Keprta’s group had asserted that magnetite crystals, structures that Earthly microorganisms make, were formed in the meteorite by Martian bacteria. In 2003, however, researchers ran computer models that indicated that geological processes occurring at temperatures too hot to sustain life could have created these magnetites.

Now science is again considering the possibility that ALH84001 is full of fossilized nano-ETs. In Thomas-Keprta’s new magnetite study, she used a focused ion beam to isolate a fraction of the magnetite. When she analyzed the sample’s chemical composition, she found that the magnetites were similar to those created by Earth microbes, and that their specific atomic makeup could not have formed at the high temperatures suggested by critics. “This doesn’t definitively show that the magnetites in ALH84001 are biological in origin,” says Dennis Bazylinski, a bacteriologist at the University of Nevada who refereed Thomas-Keprta’s paper. “But it does show that the thermal mechanism popular among those who think strongly that the magnetites do not have a biological origin is extremely unlikely. I think Kathie really put a nail in the coffin for that explanation.”

Convincing doubters that this means Mars was teeming with life, however, will be difficult. “ALH84001 is a really nice rock, full of lots of cool stuff about early Mars, but nothing in it points in the direction of life,” says David Blake, a NASA exobiologist who studied ALH84001 in the 1990s. “To look at a rock 140 million miles from where it formed and turn it into a whole world is tough.”

Recent studies by other groups of two other Martian meteorites, the Nakhla meteorite, found in Egypt, and Yamato 593, another Antarctic specimen, have yielded features similar to ALH84001. Later this summer, Thomas-Keprta will turn her ion beam on these rocks—which formed in a wet Martian environment ripe for microbes—in hopes of revealing whether it contains biological by-products, and possibly uncovering fossilized cell walls.

Even if ALH84001 really is the dead end some argue, the work has been worth it. Astrobiologists now know how incredibly difficult it is to discern biological agents from geological processes, saving researchers from a wicked learning curve when they someday get a bit of Mars itself on the table. In the next decade, the first sample return missions will bring back a pound of Martian soil, and unless it’s full of living microbes or space maggots, scientists will inspect it with the same methods developed for these meteorites. In the meantime, there are more than 200 pounds of Martian material on Earth. That’s a lot of rocks to practice on.