Last week the UK firmly threw its hat into the fusion ring with the UK Company AWE joining the National Ignition Facility (NIF) based in the US to push for energy’s Holy Grail: nuclear fusion. If fusion can be harnessed and surplus energy is harvested over and above the vast amounts of energy needed to stabilise and sustain the reaction then the long sought silver bullet, we are told, will be here. The promise of limitless clean fusion energy within fifty year, which has probably been around for fifty years is nearly here.
But, and this is the largest ‘but’ I will ever type, the technology still has some immense hurdles to cross yet.
Nuclear fusion, in layman’s terms, has all the benefits of nuclear fission, our current nuclear energy source, but with none of the radioactive material which will have an environmental impact lasting far past the life time of our children’s children.
Nuclear fusion is the chemical process where two lighter nuclei are essentially slammed together with such force that they fuse into one heavier nucleus. As they fuse they emit large quantities of energy.
Nuclear fusion is occurring in the Sun, a process called nucleosynthesis, the heat and light released in the reaction allowing life on Earth to flourish.
Having a stable reaction here on Earth is incredibly difficult as there are no materials able to withstand temperatures in excess of 100 million Kelvin which nuclear fusion reactions can reach.
This means that these plasmas need to be contained in an electric field with no part of the reactor in contact with the fusion reaction.
The two nuclei that come together can be no heavier than iron, with hydrogen atoms, the lightest element the usual candidate making the potential source of fuel for a fusion reactor the most abundant element in the Universe. Nuclear energy sources will no longer be shackled to scarce uranium deposits and suddenly we can look to the oceans for our energy.
The president of the Institute of Physics, Sir Peter Knight, claimed that a demonstration plant would be operational within the next 18 months, showing that in principle fusion can generate more energy than is required to start and maintain the fusion reaction.
He hopes that by demonstrating that this is possible, the first step to scaling the process up will begin and then the enormous benefits of fusion can be realised.
Of course however, it is not that straight forward. It never is.
Even if it possible to utilise nuclear fusion to its full potential and generate massive quantities of accessible, clean, cheap electricity we do not have the ability to effectively utilise this electricity.
Our cars and lorries currently require petrol or diesel, we have gas boilers to heat our water and warm our homes, our planes need aviation fuel to fly etc.
One solution to this, as David MacKay writes in his beguiling and sometimes scary book, Sustainable Energy – without the hot air, is to electrify as many devices as possible.
This means electric: cars; trams; boilers; machinery; ships; all lighting; heaters; you name it, everything. If fusion can provide clean, cheap, accessible electricity then everything that can use batteries, should.
Job done you might think. But then there is the very obvious question:
Is it possible to produce all the batteries needed?
And the simple answer is, no. Not in the form that batteries are currently produced. There are just not enough of the rare earth metals, such as lithium, needed to produce the batteries to substitute all our energy sources. Some people highlight the fact that we will just shift our economy and lifestyle from one dependent on oil to one dependent on rare earth metals.
So, to sum up this rather dispirited article, there have been some bold claims made recently that critical advances are occurring in our fifty year exploration for nuclear fusion. If the incredible is achieved however, there are enormous obstacles to overcome both technically and in our natural resources.
It is my opinion that it is our lifestyle, which is currently so tightly bound to high energy consumption, which is our true Achilles Heel. By reducing our energy consumption we liberate ourselves from the need for complex, technical, and possibly impossible solutions to our energy problems. Fusion may solve some of our energy problems, but it won’t solve them all.
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