Can Nuclear Fusion Save the Planet?

Our ability to transition from fossil fuels to renewable sources of energy will likely determine the fate of the planet.  Some countries are making progress toward this goal, using solar, wind and water power.  In the historic deal struck on Wednesday between the U.S. and China, for instance, China pledged that solar and wind power would account for 20 percent of China’s total energy production by 2030.  Denmark, which aims to completely eliminate its use of fossil fuels by 2050, will rely on its cutting-edge wind power industry.  Germany has focused on solar and wind power in its push to remake its electricity system, and Brazil now derives more than 75 percent of its electricity from hydro-power sources.

Yet, the real 'solution' to global warming may lie in a fourth renewable energy source, and one about which we typically hear almost nothing: nuclear fusion.

The science

Nuclear fusion isn’t new.  In fact, the oldest thermonuclear reactor is approximately 13 billion years old or the approximate age of the universe and the first star.  Our most popular fusion reactor is the sun.  Explaining the real science behind nuclear fusion is best left to the experts, but the short of it is that fusion, the reaction that gives stars their energy, is the opposite of fission.  Whereas nuclear fission creates energy by splitting one atom into two, fusion does it by joining two (hydrogen) atoms together to create one (helium), and the resulting reaction releases neutrons and an unbelievable amount of energy.

As it turns out, this is quite difficult, because in order to get the nuclei of two hydrogen atoms to fuse, one must defeat the protons’ natural tendency to repel each other.  Overcoming this tendency requires temperatures of over 100 million Kelvin (~six times hotter than the temperature at the sun’s core) and incredibly high pressure.  The prevailing method for accomplishing this is known as magnetic confinement, using a reactor known as a tokamak, and it is impossible to understand.  (There’s also another method that involves lasers, and it is even more confusing.)

Humans have been experimenting with nuclear fusion since the 1950s, and the scary amount of energy released by a fusion reaction was the impetus for the hydrogen bomb.  As our own RP Siegel pointed out, the goal of those working to turn nuclear fusion into a renewable energy source -- as opposed to a weapon -- is to take the science behind the H-bomb and control it, thereby allowing for the gradual (and self-sustaining) release of energy.  Unfortunately, doing this has heretofore proved impossible.

The challenges

We owe our fusion failures to the the incredible temperature and pressure required to ignite a fusion reaction.  Fusion demands an enormous energy input, which is almost always greater than the energy it creates, resulting in a net energy loss.  Second, because fusion scientists are effectively setting out to create a star contained by a magnetic bottle (or pounded by lasers), the necessary materials are either too expensive or simply do not exist.  To put it in context, some believe that a large-scale, functioning fusion reactor “would be a monument to human achievement surpassing the pyramids of Giza.”

Nuclear fusion’s tenuous future as a reliable energy source is perhaps best illustrated by the history of the International Thermonuclear Experimental Reactor (ITER) project.  ITER formed in 1985, when the Soviet Union proposed to the U.S. that the countries work together to explore the peaceful applications of nuclear fusion.  Since then, ITER has ballooned into a 35-country project with an estimated $50 billion price tag.  It is the largest nuclear fusion project on earth and arguably the most ambitious engineering endeavor in human history.

Unfortunately, the 30 years since ITER’s founding have been marred by political in-fighting, cronyism, budget cuts, plummeting morale, and the suffocating bureaucracy of an international organization that represents half the world’s population.

Not to mention the engineering challenges resulting from ITER’s size.  When complete, the reactor will stand 100 feet tall and weigh 23,000 tons.  It will use the largest system of superconducting magnets in the world.  Though the core will be hotter than the sun, the all-important magnets must be cooled to the temperature of deep space.  If the magnets fail, the reactor would have to contend with a force comparable to two 747s simultaneously crashing into it.

All of this is in addition to the fact that nobody knows what will happen when ITER is finally turned on (hopefully in the next decade), in part because fusion, “the most plentiful energy source in the universe, has never produced energy on Earth.”

Why do we care?

A reasonable question, then, is: Why is anyone even bothering?  Well, as Raffi Khatchadourian put it in his New Yorker story on ITER, “The technology could solve the world’s energy problems for the next 30 million years, and help save the planet from environmental catastrophe.”

How, exactly?  For one, hydrogen -- the element used to create the fusion reaction -- is the most abundant atom in the universe, meaning the reactor’s “fuel” is likely limitless and could be sourced from seawater and the lithium found in the Earth’s crust.  Fusion reactors are also safe (they produce less radiation than we live with every day); clean (there’s no combustion, so there’s no pollution); and will create less waste than fission reactors.

Simply put, “Creating miniature stars on Earth is a non-optional part of humanity’s future.”

Causes for hope and despair

Last month, the Pentagon’s largest supplier, Lockheed Martin, announced that its Skunk Works program was a year away from completing a relatively tiny, 100-megawatt test fusion reactor -- and that a prototype could be completed in five years.  At 7-by-10 feet, the reactor could fit in a tractor trailer and produce roughly a fifth of the energy that ITER’s gargantuan reactor will hopefully generate.  The ostensible purpose of Lockheed's announcement was to secure partners in academia, industry and government in order to advance the work, which could end up yielding a commercial application in a decade.  Amazing, right?

Well, the scientific community’s reaction to the Lockheed announcement was ... muted at best.  Lockheed’s supposed 'breakthrough' was the creation of a magnetic bottle' that would contain the heat and pressure of the fusion reaction; however, this is the same technology that has been around for 50-plus years, and Lockheed did not explain how its tokamak was different and able to achieve a net energy gain.  In fact, it offered no data at all, and the little information it did release suggested that it might not even have the basic science right.

Meanwhile, key structures are still being built at ITER -- a fact that, in and of itself, is reason for hope -- and the scientific community continues to make incremental progress toward the goal of net energy gain.

Here in the U.S., things look a bit bleaker.  In July, a U.S. Senate panel voted to zero-out America’s funding for ITER, and the red wave brought by last week’s midterm elections should usher in a Congress that is even more hostile to climate science.

As always, then, a cloud of uncertainly hovers over the future of nuclear fusion even as the future of the planet depend on its success.

Image credit: Flickr/fusionforenergy