Fusion is the power source of the future, according to science fiction, but did you know that scientists have been working on this for decades, and are drawing ever closer to harnessing the power of the Sun?
When we look up into the sky, and see the Sun burning brightly during the day, or the stars twinkling at night, we are seeing the products of fusion. Each of these stars, our Sun included, is an immense ball of mostly hydrogen gas, and the weight of the star crushes all that hydrogen down towards the middle, where temperatures reach somewhere around 15 million degrees Celsius. These incredible temperatures cause the hydrogen atoms to fly around so fast that they slam into one other with enough force that they fuse, producing an atom of helium, along with some energy.
A star like our Sun converts roughly 600 million tonnes of hydrogen into helium every second. With just one gram of hydrogen containing 602,300,000,000,000,000,000,000 atoms, when tally everything up, the little bit of energy released by each pair of atoms fusing turns into A LOT OF ENERGY. This energy is absorbed by the outer layers of the Sun, turning them into churning circulations of hydrogen, and this outward force keeps the star from collapsing in on itself. The energy that reaches the “surface” of the Sun escapes into space, providing us with light and heating the daylight side of our planet.
Now, if we could harness just a fraction of that energy, we would never need another source of energy, ever.
We can’t bring a star down to Earth, of course, or even a piece of one, but what if we could safely mimic the way it generates energy?
This is the story behind the new documentary film, Let There Be Light, co-directed by Mila Aung-Thwin and Van Royko, which made its Canadian debut at Toronto’s 2017 Hot Docs Festival.
How does a fusion reactor work?
There has been this somewhat “pie in the sky” view of fusion power, for decades now. Stories in the media have made promises that were never kept. For awhile “cold fusion” was the big thing, as it was supposed to deliver limitless energy by fusing elements at room temperature (or close to it). To date, while a few projects have produced “first plasma”, if only for a fraction of a second, we have yet to see actual fusion power produced in any significant quantities.
When it comes down to it, the concept of fusion power is simple enough – get two atomic nuclei to bang into one another with sufficient speed that they stick together, and harness the energy that is produced by that collision. Actually accomplishing that, using technology, instead of the gravitational forces at the core of a star, is far more complicated than it sounds, though.
For one, in order to overcome the natural repulsion that atomic nuclei have for one another, you have to get them moving so quickly that their speed overcomes that repulsive force. When you’re working with a plasma gas, this means driving up the heat, and it just so happens that if you want to do that in a reactor, you need to heat the plasma to around 150 million degrees.
While we still do not have a fusion reactor delivering power to our electric grids, today, Let There Be Light gives us a fascinating look into just how much progress has been made!
One of the largest, most expensive, and probably the most promising fusion project in the world is ITER – the International Thermonuclear Experimental Reactor.
Located in the south of France, this multinational effort has already been going for decades now, slowly evolving over the years into its present state. The goal of ITER is to build a Tokamak reactor, which will produce a giant magnetic bubble, shaped like a doughnut, that will be used to confine a volume of heated, electrically charged gas, known as a plasma. Keeping the plasma away from the sides of the container, while it is heated up to 150 million degrees C (by something like lasers or acoustic waves), the Tokamak will act as the “containment field” for the fusion of the plasma particles to take place in.
A cut-away view of the ITER Tokamak. Credit: ITER Organization
We sat down with Mark Henderson, the scientist in charge of the ITER project’s microwave heating system, to talk about ITER, its importance to the world and the obstacles the project faces.
Fusion projects are not all immense, multinational efforts, though. Another promising one detailed in the film is taking place right here in Canada, just east of Vancouver, in Burnaby, British Columbia.
Although ITER may have the best chances to actually produce fusion energy, General Fusion’s plan is to produce a smaller, cheaper way, which has a better chance of actually delivering a viable commercial reactor, in the end.
The way it will work is that it suspends a metallic fluid inside the fusion chamber, with the plasma at the very core. The metallic fluid keeps the plasma from touching the sides of the chamber, while at the same time, it acts to compress the plasma, when all the pistons along the outside of the chamber thrust inward. This increased pressure makes it easier to pump the plasma up to the temperatures needed for fusion to take place.
The core and pistons of the General Fusion reactor. Credit: Eye Steel Film
Michel Laberge, Founder and Chief Science Officer of General Fusion, talked with us about this much smaller project, and why it may be even more important than larger efforts like ITER.
When will we see fusion power?
When it comes down to it, this is the big question. With all the efforts being put into this, when will we actually see a fusion reactor come online and produce energy that feeds into our electric grids?
The answer, really, depends on our priorities, and it depends on our politicians.
If you like the idea of limitless, safe, clean energy, these projects deserve your attention, and they deserve substantial investments, both from private sources and from our governments. Even then, it still could take a decade or more to achieve their initial goals, and even longer for a fully operational power plant. That should not deter us, though.
With the state of the world, today, the need for long-term thinking is crucial, especially when it comes to thinking of our energy needs. And really, when it comes down to it, what’s a couple of decades, when it comes to the potential to power human civilization for millions of years to come?
Source: The Weather Network