Fusion Reactors
August 26, 2019
I just finished a weekend deep dive into fusion reactors as a promising climate change mitigation technology. Wow! There are some exciting things happening.
Here’s what I learned:
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They’re clean and practical
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The plasma in reactors runs hot: temperatures start at 100,000,000C. A Google company, TAE, is pursuing a method that requires temperatures of 2,000,000,000C+.
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Nuclear reactors have existed since 1954. Science is there, but input energy < output energy.
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There’s a viable argument to be made about 2030 fusion on the grid.
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Due to short timeline, private funding is coming into the space. Most recently Commonwealth Fusion.
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Industry consensus is that it’s an engineering, not a science problem now. How can we make net-energy-positive reactors as small and cheap as possible? Realistic lower bound for $/W is $1.8 (50% cheaper than any source) but current projections are around $20.
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Fusion efficiency is proportional to magnetic field strength to the fourth power (B^4)
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This means that any increase in magnet strength (specifically, superconductor fields) has a massive impact on design feasibility.
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Every year batteries are getting better (roughly linearly). In 2010 state of the art was 8T. This year @NationalMagLab created a magnet with a 46.5T field strength (6x increase in 9 years)
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One type of magnet, REBCO, has revolutionized superconductors since 2014. It’s really simple (4 layers: copper, silver, a buffer, and stainless steel) but produces great results. We don’t know why it works as well as it does.
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There are currently 17 companies pursuing fusion with a variety of techniques. It’s an exciting time as fusion changes from an “if” to a “when.”
If you’re interested in learning more, I recommend:
This primer:
https://link.medium.com/HxAEK3nlsZ And this (technical) video:
Written by Brent Baumgartner. He lives and works in Charlottesville at TwinThread, building data-driven products. You should follow him on Twitter