by Michio Kaku
• Creating algae blooms. Another suggestion is to dump iron-based chemicals into the oceans. These mineral nutrients will cause algae to thrive in the ocean, which in turn will increase the amount of carbon dioxide that is absorbed by the algae. However, after Planktos, a corporation based in California, announced that it would unilaterally begin a private effort to fertilize part of the South Atlantic with iron—hoping to deliberately spawn plankton blooms that would absorb the carbon dioxide in the air—countries bound by the London Convention, which regulates dumping at sea, issued a “statement of concern” about this effort. Also, a United Nations group called for a temporary moratorium on such experiments. The experiment was ended when Planktos ran out of funds.
• Carbon sequestration. Yet another possibility is to use carbon sequestration, a process by which the carbon dioxide emitted from coal-burning power plants is liquefied and then separated from the environment, perhaps by being buried underground. Although this might work in principle, it is a very expensive process, and it cannot remove the carbon dioxide that has already been lofted into the atmosphere. In 2009, engineers were carefully monitoring the first major test of carbon sequestration. The huge Mountaineer power plant, built in 1980 in West Virginia, was retrofitted to separate carbon dioxide from the environment, making it the United States’ first electricity-generating coal-burning plant to experiment with sequestration. The liquefied gas will be injected 7,800 feet underground, eventually into a layer of dolomite. The liquid will eventually form a mass thirty to forty feet high and hundreds of yards long. The plant’s owner, American Electric Power, plans to inject 100,000 tons of carbon dioxide annually for two to five years. This is only 1.5 percent of the plant’s yearly emission, but eventually the system could capture up to 90 percent. The initial costs are about $73 million. But if it’s successful, then this model could rapidly be disseminated to other sites such as four nearby giant coal-burning plants generating 6 billion watts of energy (so much that this area is dubbed Megawatt Valley). There are large unknowns: it is not clear if the carbon dioxide will eventually migrate or if the gas will combine with water, perhaps creating carbonic acid that may poison groundwater. However, if the project is a success, it may very well be part of a mix of technologies used to deal with global warming.
• Genetic engineering. Another proposal is to use genetic engineering to specifically create life-forms that can absorb large quantities of carbon dioxide. One enthusiastic promoter of this approach is J. Craig Venter, who gained fame and fortune pioneering high-speed techniques that successfully led to sequencing the human genome years ahead of schedule. “We view the genome as the software, or even the operating system, of the cell,” he says. His goal is to rewrite that software, so that microbes can be genetically modified, or even constructed almost from scratch, so that they absorb the carbon dioxide from coal-burning plants and convert it into useful substances, such as natural gas. He notes, “There are already thousands, perhaps millions, of organisms on our planet that know how to do this.” The trick is to modify them so that they can increase their output and also flourish in a coal-fired plant. “We think this field has tremendous potential to replace the petrochemical industry, possibly within a decade,” he said optimistically.
Princeton physicist Freeman Dyson has advocated another variation, creating a genetically engineered variety of trees that would be adept at absorbing carbon dioxide. He has stated that perhaps a trillion such trees might be enough to control the carbon dioxide in the air. In his paper “Can We Control the Carbon Dioxide in the Atmosphere?” he advocated creating a “carbon bank” of “fast-growing trees” to regulate carbon dioxide levels.
However, as with any plan to use genetic engineering on a large scale, one must be careful about side effects. One cannot recall a life-form in the same way that we can recall a defective car. Once it is released into the environment, the genetically engineered life-form may have unintended consequences for other life-forms, especially if it displaces local species of plants and upsets the balance of the food chain.
Sadly, there has been a conspicuous lack of interest among politicians to fund any of these plans. However, one day, global warming will become so painful and disruptive that politicians will be forced to implement some of them.
The critical period will be the next few decades. By midcentury, we should be in the hydrogen age, where a combination of fusion, solar power, and renewables should give us an economy that is much less dependent on fossil fuel consumption. A combination of market forces and advances in hydrogen technology should give us a long-term solution to global warming. The danger period is now, before a hydrogen economy is in place. In the short term, fossil fuels are still the cheapest way to generate power, and hence global warming will pose a danger for decades to come.
FUSION POWER
By midcentury, a new option arises that is a game changer: fusion. By that time, it should be the most viable of all technical fixes, perhaps giving us a permanent solution to the problem. While fission power relies on splitting the uranium atom, thereby creating energy (and a large amount of nuclear waste), fusion power relies on fusing hydrogen atoms with great heat, thereby releasing vastly more energy (with very little waste).
Unlike fission power, fusion power unleashes the nuclear energy of the sun. Buried deep inside the hydrogen atom is the energy source of the universe. Fusion power lights up the sun and the heavens. It is the secret of the stars. Anyone who can successfully master fusion power will have unleashed unlimited eternal energy. And the fuel for these fusion plants comes from ordinary seawater. Pound for pound, fusion releases 10 million times more energy than gasoline. An 8-ounce glass of water is equal to the energy content of 500,000 barrels of petroleum.
Fusion (not fission) is nature’s preferred way to energize the universe. In star formation, a hydrogen-rich ball of gas is gradually compressed by gravity, until it starts to heat up to enormous temperatures. When the gas reaches around 50 million degrees or so (which varies depending on the specific conditions), the hydrogen nuclei inside the gas are slammed into one another, until they fuse to form helium. In the process, vast amounts of energy are released, which causes the gas to ignite. (More precisely, the compression must satisfy something called Lawson’s criterion, which states that you have to compress hydrogen gas of a certain density to a certain temperature for a certain amount of time. If these three conditions involving density, temperature, and time are met, you have a fusion reaction, whether it is a hydrogen bomb, a star, or a fusion in a reactor.)
So that is the key: heating and compressing hydrogen gas until the nuclei fuse, releasing cosmic amounts of energy.
But previous attempts to harness this cosmic power have failed. It is a fiendishly difficult task to heat hydrogen gas to tens of millions of degrees, until the protons fuse to form helium gas and release vast amounts of energy.
Moreover, the public is cynical about these claims, since every twenty years scientists claim that fusion power is twenty years away. But after decades of overoptimistic claims, physicists are increasingly convinced that fusion power is finally arriving, perhaps as early as 2030. Sometime by midcentury, we may see fusion plants dotting the countryside.
The public has a right to be skeptical about fusion, since there have been so many hoaxes, frauds, and failures in the past. Back in 1951, when the United States and the Soviet Union were gripped in Cold War frenzy and were feverishly developing the first hydrogen bomb, President Juan Perón of Argentina announced, with huge fanfare and a media blitz, that his country’s scientists had made a breakthrough in controlling the power of the sun. The story sparked a firestorm of publicity. It seemed unbelievable, yet it made the front page of the New York Times. Argentina, boasted Perón, had scored a major scientific breakthrough where the superpowers had failed. An unknown German-speaking scientist, Ronald Richter, had convinced Perón to fund his “thermotron,” which promised unlimited energy and eternal glory for Argentina.
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p; The American scientific community, which was still grappling with fusion in the fierce race with Russia to produce the H-bomb, declared that the claim was nonsense. Atomic scientist Ralph Lapp said, “I know what the other material is that the Argentines are using. It’s baloney.”
The press quickly dubbed it the Baloney Bomb. Atomic scientist David Lilienthal was asked if there was the “slightest chance” the Argentines could be correct. He shot back, “Less than that.”
Under intense pressure, Perón simply dug in his heels, hinting that the superpowers were jealous that Argentina had scooped them. The moment of truth finally came the next year, when Perón’s representatives visited Richter’s lab. Under fire, Richter was acting increasingly erratic and bizarre. When inspectors arrived, he blew the laboratory door off using tanks of oxygen and then scribbled on a piece of paper the words “atomic energy.” He ordered gunpowder to be injected into the reactor. The verdict was that he was probably insane. When inspectors placed a piece of radium next to Richter’s “radiation counters,” nothing happened, so clearly his equipment was fraudulent. Richter was later arrested.
But the most celebrated case was that of Stanley Pons and Martin Fleischmann, two well-respected chemists from the University of Utah who in 1989 claimed to have mastered “cold fusion,” that is, fusion at room temperature. They claimed to have placed palladium metal in water, which then somehow magically compressed hydrogen atoms until they fused into helium, releasing the power of the sun on a tabletop.
The shock was immediate. Almost every newspaper in the world put this discovery on its front page. Overnight, journalists talked of ending the energy crisis and ushering in a new age of unlimited energy. A feeding frenzy hit the world media. The state of Utah immediately passed a $5 million bill to create a National Institute for Cold Fusion. Even Japanese car manufacturers began to donate millions of dollars to promote research in this hot new field. A cultlike following began to emerge based around cold fusion.
Unlike Richter, Pons and Fleischmann were well respected in the scientific community and were glad to share their results with others. They carefully laid out their equipment and their data for the world to see.
But then things got complicated. Since the apparatus was so simple, groups around the world tried to duplicate these astonishing results. Unfortunately, most groups failed to find any net release of energy, declaring cold fusion a dead end. However, the story was kept alive because there were sporadic claims that certain groups had successfully duplicated the experiment.
Finally, the physics community weighed in. They analyzed Pons and Fleischmann’s equations, and found them deficient. First, if their claims were correct, a blistering barrage of neutrons would have radiated from the glass of water, killing Pons and Fleischmann. (In a typical fusion reaction, two hydrogen nuclei are slammed together and fuse, creating energy, a helium nuclei, and also a neutron.) So the fact that Pons and Fleischmann were still alive meant the experiment hadn’t worked. If their experiments had produced cold fusion, they would be dying of radiation burns. Second, more than likely Pons and Fleischmann had found a chemical reaction rather than a thermonuclear reaction. And last, the physicists concluded, palladium metal cannot bind hydrogen atoms closely enough to cause the hydrogen to fuse into helium. It would violate the laws of the quantum theory.
But the controversy has not died down, even today. There are still occasional claims that someone has achieved cold fusion. The problem is that no one has been able to reliably attain cold fusion on demand. After all, what is the point of making an automobile engine if it works only occasionally? Science is based on reproducible, testable, and falsifiable results that work every time.
HOT FUSION
But the advantages of fusion power are so great that many scientists have heeded its siren call.
For example, fusion creates minimal pollution. It is relatively clean, and is nature’s way of energizing the universe. One by-product of fusion is helium gas, which is actually commercially valuable. Another is the radioactive steel of the fusion chamber, which eventually has to be buried. It is mildly dangerous only for a few decades. But a fusion plant produces an insignificant amount of nuclear waste compared to a standard uranium fission plant (which produces thirty tons of high-level nuclear waste per year that lasts for thousands to tens of millions of years).
Also, fusion plants cannot suffer a catastrophic meltdown. Uranium fission plants, precisely because they contain tons of high-level nuclear waste in their core, produce volatile amounts of heat even after shutdown. It is this residual heat that can eventually melt the solid steel and enter the groundwater, creating a steam explosion and the nightmare of the China Syndrome accident.
Fusion plants are inherently safer. A “fusion meltdown” is a contradiction in terms. For example, if one were to shut down a fusion reactor’s magnetic field, the hot plasma would hit the walls of the chamber and the fusion process would stop immediately. So a fusion plant, instead of undergoing a runaway chain reaction, spontaneously turns itself off in case of an accident.
“Even if the plant were flattened, the radiation level one kilometer outside the fence would be so small that evacuation would not be necessary,” says Farrokh Najmabadi, who directs the Center for Energy Research at the University of California at San Diego.
Although commercial fusion power has all these marvelous advantages, there is still one small detail: it doesn’t exist. No one has yet produced an operating fusion plant.
But physicists are cautiously optimistic. “A decade ago, some scientists questioned whether fusion was possible, even in the lab. We now know that fusion will work. The question is whether it is economically practical,” says David E. Baldwin of General Atomics, who oversees one of the largest fusion reactors in the United States, the DIII-D.
NIF—FUSION BY LASER
All this could change rather dramatically in the next few years.
Several approaches are being tried simultaneously, and after decades of false starts, physicists are convinced that they will finally attain fusion. In France, there is the International Thermonuclear Experimental Reactor (ITER), backed by many European nations, the United States, Japan, and others. And in the United States, there is the National Ignition Facility (NIF).
I had a chance to visit the NIF laser fusion machine, and it is a colossal sight. Because of the close connection with hydrogen bombs, the NIF reactor is based at the Lawrence Livermore National Laboratory, where the military designs hydrogen warheads. I had to pass through many layers of security to finally gain access.
But when I reached the reactor, it was a truly awesome experience. I am used to seeing lasers in university laboratories (in fact, one of the largest laser laboratories in New York State is directly beneath my office at the City University of New York), but seeing the NIF facility was overwhelming. It is housed in a ten-story building the size of three football fields, with 192 giant laser beams being fired down a long tunnel. It is the largest laser system in the world, delivering sixty times more energy than any previous one.
After these laser beams are fired down this long tunnel, they eventually hit an array of mirrors that focus each beam onto a tiny pinhead-size target, consisting of deuterium and tritium (two isotopes of hydrogen). Incredibly, 500 trillion watts of laser power are focused onto a tiny pellet that is barely visible to the naked eye, scorching it to 100 million degrees, much hotter than the center of the sun. (The energy of that colossal pulse is equivalent to the output of half a million nuclear power plants in a brief instant.) The surface of this microscopic pellet is quickly vaporized, which unleashes a shock wave that collapses the pellet and unleashes the power of fusion.
It was completed in 2009, and is currently undergoing tests. If all goes well, it may be the first machine to create as much energy as it consumes. Although this machine is not designed to produce commercial electrical power, it is designed to show that laser beams can be focused to heat hydrogen-rich materials and produce net
energy.
I talked to one of the directors of the NIF facility, Edward Moses, about his hopes and dreams for his project. Wearing a hard hat, he looked more like a construction worker than a top nuclear physicist in charge of the largest laser lab in the world. He admitted to me that in the past there have been numerous false starts. But this, he believed, was the real thing: he and his team were about to realize an important achievement, one that will enter the history books, the first to peacefully capture the power of the sun on earth. Talking to him, you realize how projects like NIF are kept alive by the passion and energy of their true believers. He savored the day, he told me, when he could invite the president of the United States to this laboratory to announce that history had just been made.