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Editor's Note: Mathias is currently working on a masters in energy and environmental engineering at NTNU in Norway. In his spare time he runs EnergyInformative.org, a site that focuses on informing and promoting the use of clean, renewable energy technologies and increased energy efficiency. Connect with Mathias on Google+ or send him an email.
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What is Nuclear Fusion?
Nuclear fusion has a lot of advantages over fission, which is what we use in today’s nuclear reactors. How does fusion compare to fission when it comes to being sustainable and green? Are these appropriate labels? Let’s look closer.
From Albert Einstein’s renowned equation E = mc^2, we can derive how much energy is released when there is a net loss in mass. Fission refers to the process where an atom is split into two smaller ones. The larger atom is heavier than the two smaller atoms are combined. In other words, we have a net loss of mass that is converted into heat energy.
Fusion is the name of the process where two smaller atoms melt together and becomes a larger atom, also resulting in a net loss of mass and a gain in useful heat energy.
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Why Fusion is Superior
There are several reasons why scientists refuse to give up when it comes to fusion power. These are the most important ones:
- Fusion fuel is abundant. We can harness energy from fusion processes that uses deuterium, also known as heavy hydrogen, as a fuel. The energy density is astonishing: The amount of deuterium that is extracted from 1L seawater is equivalent in terms of energy to 300 L petrol – We have 30 million years worth of fusion fuel in seawater. Did someone say sustainable?
- Fusion power is certainly greener than conventional ways of harnessing energy that are fueled by fossil fuels and coal: There are no carbon-emissions when it comes to fusion. What about radioactive waste? The truth is that there is some, but to a much lesser degree compared to the waste that comes with fission reactors.
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Challenges With Fusion
The advantages of fusion power almost sounds to good to be true. Well, they don’t come without a price. To reap them, we need to overcome a set of major challenges, the by far hardest one being:
- The heat that is necessary to melt two deuterium atoms together (hydrogen fusion) is almost unimaginable: 10-14 million Kelvin. To sustain this amount of heat, we need major technological breakthroughs in material engineering.
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We Have Already Done Nuclear Fusion
Yes it’s true. On several occasions we have actually gotten the fusion process going. The so far most successful experiment was conducted in 1997, where scientists fired up JET (Joint European Torus), and generated 16 MW through fusion. On the other hand, the input of energy that was required to achieve this exceeded the output many times over.
The image to the left is an illustration of the inside of JET-reactor, which is built on the concept of nuclear tokamaks, a reactor-type that uses magnetic fields to withstand the heat, originally developed by Soviet physicist back in the 50’s.
ITER (International Thermonuclear Experimental Reactor), which is a coalition of seven nations that continues to push fusion forward, is planning to start testing in France already in 2018. We can only speculate in if the $23 billion project will get us closer to realizing fusion power on large-scale, but ITER sure holds a lot of promise.
The achievement of fusion power represents a new paradigm shift in energy: The times where resource has dictated the energy world will be replaced by knowledge. We will no longer be bound by quantities of fossil fuels, wind or solar resources, but instead have the knowledge to derive all the energy we need through something as simple and abundant as seawater. This is why nuclear fusion is the holy grail of energy.
- Image credit: Lawrence Berkeley Labs