A Bottled Star on Earth; Powered by Sea Water
Ever since 1934 we humans have invested billions of dollars in a technology that hasn’t even proven itself to be usable yet. When this technology does become commercially viable, the potential for us could be unimaginably huge. This technology is Nuclear Fusion.
Nuclear Fusion is the process the sun uses to light our day and warm our earth. Fusion energy will be so efficient that a glass of sea water could provide the same energy as a barrel of oil with no waste.
How is this possible? Let me explain.
The Magic
Nuclear Fusion happens when atoms are moving extremely fast. As you may have learned in school, the hotter the atoms are the more energy they have, and the faster they move.
Stars have to be so hot that their atoms ionize. They loose their electrons and the remaining nuclei bounce around in a lump of plasma. Because nuclei are positively charged, they repel each other. This means that the nuclei need to be moving so fast that the forces of repulsion are overcome.
The center of our sun is 15 million degrees Celsius. That is the temperature needed for plasma to form. Well . . . technically that’s a lie. 100 million degrees Celsius is needed to form plasma here on earth. Stars on the other hand in a sense cheat.
Stars are so large that the pressure at their core is immense. This pressure helps form the plasma. This makes you wonder, how will we ever enclose something that is hotter than the center of the sun? Well, heat doesn’t necessarily mean temperature, but rather that the particles vibrate faster. Since the plasma has such as low density, it doesn’t have as much contact with other things to transfer heat.
A fluorescent tube that contains something like neon or argon can be 10 000 degrees Celsius! Yet due to the gasses low density, the tube can be touched without harm. The heat from the gas has a hard time transferring to the tube.
So now you may be wondering . . . so where does the actual fusion come in. Well read on.
While all the nuclei are whizzing around in the plasma state, with enough heat/energy/speed the nuclei combine together forming a new element. If you remember from grade 9 science, the number of protons determines the element. So when 2 nuclei (which contain protons) merge, the number of protons change, so the element changes.
So . . . we changed the element of something. What does this mean? A vast amount energy!
When the two nuclei fuse, energy is released in the forms of heat and light. This heat can be converted to electricity for us to use. This process of “fusing” nuclei is where nuclear fusion gets its name.
Sea Water Fuel
I said this before, fusion can be done with sea water. You may be wondering, why seawater?
First some background info, then the interesting part.
Fusion is not Fission. Fission splits heavy atoms like uranium into smaller atoms. Fusion combines lighter atoms into slightly heavier ones.
Hydrogen and helium are the 1st and 2nd elements of the periodic table, and are therefore the lightest. There are different isotopes of elements. An isotope is the element but with more neutrons.
Seawater contains hydrogen, more specifically deuterium. Deuterium is an isotope of hydrogen. It has an extra neutron. This is important. When you fuse specific isotopes of hydrogen you can get other isotopes of hydrogen and helium. These fuse forming other isotopes of hydrogen and helium. This “chain reaction” ends up with things such as helium- 3 which can fuse releasing energy. And other isotopes to continue the process.
One glass of pure deuterium could power a house for 865 years.
This is extremely efficient.
And so naturally, private companies have started to pop up in this field.
Helion
Helion was founded by David Kirtley in 2013.
They want to enable a future with unlimited clean energy.
To accomplish that they have built a plasma accelerator. This accelerator first raises the fusion fuel temperature to 100 million degrees Celsius. Then it extracts the electricity from the electromagnetic fields formed from the fusion.
Their plasma accelerator is 6 ft tall and 40 ft long.
On both ends Deuterium and helium 3 are heated into plasma in a Field reversed configuration. This simply means magnets keep the plasma in a ring shape. This prevents it from touching the sides of the accelerator. If the plasma touches the sides it would transfer its heat and cool down quickly.
The plasma on both ends is then accelerated and squeezed into the central compartment by magnets. Both sides collide in the middle compressing with the help of a magnetic field. The temperature is now 100 million degrees Celsius!
Fusion now starts to happen. The deuterium and helium-3 particles are moving fast enough to overcome the forces that would otherwise keep them apart.
As they fuse and energy is released the plasma expands. This is all fancy physics, but its the next part that actually generates electricity.
When the plasma expands it releases charged particles. These particles push back against the magnetic field compressing the plasma. This changes the electrical current of the electromagnet. According to Faraday’s law, this change in current can be directly converted into electricity. Faraday's law is the basis of electrical generators.
Helion’s accelerator is still a work in progress yet they are still at the forefront of fusion research. They are the first privately funded company to reach 100 Million Degrees Celsius plasma temperatures.
One of the interesting things about Helion is that they create there own fuel. They are the first company to produce helium-3 in an industrial process. This can be used for fusion energy. Helium is very rare. It is lighter than air so it often floats off into space. Others have considered going to the moon to mine helium-3 dust that may have accumulated over the years.
Helion is no doubt a very interesting company. Yet there are other ways to create fusion and sustain plasma.
Types of fusion
There are 2 main ways to create the plasma for fusion.
- Magnetic Confinement Fusion (MCF)
- Inertial Confinement
Magnetic Confinement Fusion (MCF)
MCF is similar to what Helion uses. Electromagnets are used to hold fusion fuel in a torus shape and to accelerate it. The magnets suspend the plasma and prevent it from touching the sides of the container. If the plasma touches the sides the plasma would cool down rapidly. The magnets often also heat up the plasma similar to an induction stove.
The International Thermonuclear Experimental Reactor (ITER) is an example of MCF.
ITER will be the largest tomahawk fusion reactor in the world. It is a collaboration between 35 nations and is being built in France.
Inertial Confinement
Inertial Confinement rather than using magnets to heat up and suspend the plasma it uses inertia and lasers. One of the most powerful lasers in the world is used in the National Ignition Facility (NIF) in California. They are a government organization dedicated to setting things on fire.
Multiple lasers are focused on a single pellet of fuel smaller than a jellybean. This fuel is usually a mix of hydrogen-2 (deuterium) and hydrogen-3 (tritium). The lasers heats up the fuel until it implodes. The inside ignites the layers of the fuel from the inside and sustains fusion. The pellet is held in place by its own inertia during the process.
So now begs the question, why isn’t fusion commonplace today?
A Funding gamble
The biggest barrier to fusion is funding. Fusion is a billion dollar gamble. Governments are reluctant to spend money on fusion research. Especially when that same money could also be used for other renewable energy sources.
There's an ongoing joke that says nuclear fusion is always 30 years away.
We can barely sustain fusion for 7 minutes. It currently takes more energy to create fusion than the fusion produces. Fusion is still progressing.
Yet the impact nuclear fusion could have is tremendous. This is a technology that could mean near unlimited, clean and affordable energy
As Lev Grossman, the Lead Technology Writer for the Time Magazine said:
It’s an energy source so cheap and clean and plentiful that it would create an inflection point in human history, an energy singularity that would leave no industry untouched. Fusion would mean the end of fossil fuels. It would be the greatest antidote to climate change that the human race could reasonably ask for.
TL;DR
- Fusion is when 2 atoms “fuse” into 1 atom
- Fusion requires immense heat
- This process releases energy and particles can be converted into useable electricity
- Fusion could one day use elements common in sea water as clean fuel
- There are 2 main types of fusion: Magnetic Confinement Fusion (MCF)
and Inertial Confinement - MCF uses magnets to suspend and heat up plasma
- Inertial Confinement uses lasers to implode fuel pellets
- Helion is a privately funded companion working on fusion reactors
- One of the biggest barriers is that fusion is still unproven tech, funding it is a billion dollar gamble
- Current reactors require more energy than they produce
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