Fusion Futures: Imagining a world of energy abundance

There is a limited amount of petroleum in the world. Combustion of all of the gas that is left will not only alter the Earth’s atmosphere, but will leave us with relatively few viable alternatives to fill the energetic void left by fossil fuels.

This may lead us to ask the question: will we be able to support the population of the planet when that happens? Assuming the population will continue to increase, it seems unlikely that the current lifestyle we have become accustomed to will continue to be supportable. After all, petroleum was produced over a period of eons, and will have been consumed in a mere blink of an eye. It is hard to imagine that any of the renewable energy sources we have available will be able to meet that level of energy output.

And yet, who would have thought some few centuries ago that it would become possible to cleave the nucleus of an atom, releasing an almost incomprehensible amount of energy? If such a feat is possible for humans, then the realm of sci-fi is not necessarily out of reach. What might seem impossible for an evolved species just recently having acquired language and even more recently agriculture, should not be automatically discounted as fantasy.

One contender to fill the void is nuclear fusion. It portends to have all of the energy producing capacity of current atomic energy technology, but without the difficult radioactive waste products. And since the fuel source can be hydrogen isotopes, it is virtually inexhaustible. That is, in theory.

Over the ages, scientists have sought the sort of holy grail of energy production which is the perpetual motion machine. Always there is some flaw: some escape valve which admits of the inescapable deficiency. Always the designs fail. That is because, they are trying to defy the laws of physics, or perhaps more fundamentally the laws of mathematics and logic. Since the vector of causation can not be the impetus for its own motion. Always energy comes from outside the system, is injected into it. In the case of petroleum, the energy is from eons of gravitational pressure. In the case of nuclear energy, it is atomic energy from the formation of the universe.

The energy created by nuclear fusion is also atomic in nature. It is caused by the fusing of two light isotopes for form a higher “ranked” element (ie a higher number on the periodic table). The fusion reaction is already happening all the time: the energy collected by solar panels is an indirect byproduct of the fusing of hydrogen atoms into helium in the Sun. The idea of a nuclear fusion reactor is to recreate that chemical process here on Earth.

The process is as follows: typically two hydrogen isotopes are used, deuterium and tritium. When forced together at extremely high temperature and pressure (at least 100 million degrees C), the strong attractive force of the protons overcomes the weak repulsive electromagnetic force of the electrons, and the atoms merge, forming a helium atom and releasing a neutron whose energy can be collected and redirected to other uses.

It might seem creating a nuclear fireball on Earth might be dangerous. But since the process requires such immense amounts of heat to sustain it, a runaway reaction is unlikely.

The bigger obstacles are engineering problems. To create and sustain enough heat to cause plasma and subsequently fusion to occur, there are many parts subject to corrosion and breakdowns. And the released helium has the potential to make contacted surfaces radioactive. But when stated thusly they would not seem impossible to overcome.

Is it a pipe dream? Well, there is enough promise to justify the funding and construction of a huge reactor, just to demonstrate the viability of the concept. It is a multi-billion dollar project called ITER, and they aim to have a net positive heat input to energy output system by 2035. That’s less than 15 years away. Although initially appearing to be an ever-receding phantom, steps and aspects of the problem are being solved incrementally. So far the best efficiency rate achieved has been 66%. That is, of the heat created to sustain the reaction, 66% was converted to usable energy. And it would take a lot more than a net positive to actually support the energy needs of the globe.

But I think it’s safe to say the possibility of an inexhaustible energy future is not mere fantasy. The perpetual motion machine has the air of a kind of mythos: the product of naive philosophy and untethered imagination. But humanity may live to see it come into fruition.