Thread by @BarclayBenedict

I've finally had time to do a new Substack post.

Inspired by the breakthrough achieved by the Lawrence Livermore National Laboratory, it's on #fusion power.

And particularly how that relates to the energy transition and achieving net zero.

🧵

thegreentransition.substack.com/p/fusion-power

When discussing breakthroughs in fusion power, it is worth remembering the running joke that “it’s the energy source of the future—always has been, always will be”.

Promising unlimited energy and delivering it are two different things.

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First, what is the difference between fission and fusion?

In nuclear fission (the technology used at all existing nuclear power plants), big atoms release energy when they split into smaller fragments.

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In nuclear fusion, two isotopes of hydrogen (deuterium and tritium) release energy when they combine (fuse) to form helium.

In order to fuse, they must be in a plasma state. A plasma is the 4th state of matter; it's a bit like a gas, but with charged particles.

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To achieve the plasma state, you need a very high temperature. In practice, the temperature inside fusion reactors reaches at least 100 million degrees Celsius, which is around 10 times as hot as the temperature inside the Sun.

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Research into fusion power has been going on for decades. The Joint European Torus (JET) at Culham in Oxfordshire was commissioned in 1983.

It has achieved many successes, but it is has never managed to release more energy from a fusion reaction than was used to initiate it.

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That goal is called fusion ignition or scientific energy breakeven.

And it's what the National Ignition Facility at the Lawrence Livermore National Laboratory (LLNL) achieved last month. With big caveats.

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2.05 MJ of energy was used to heat the fuel, and 3.15 MJ of energy was released. That’s a 50% energy gain. But...

1. The amount of "surplus" energy was tiny – around 0.3 kWh.

2. The calculation excludes over 500 MJ of energy consumed by the lasers.

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So how does fusion power go from this to useful power stations?

ITER is the world's biggest fusion power experiment. A collaboration between the EU, US, China, Japan, India, Korea and Russia.

It is based on JET's technology, which is different from the LLNL approach.

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ITER is building a "Tokamak" – a type of fusion reactor – at Cadarache in France.

This is a huge project, and construction of the buildings is nearing completion. But the timeline keeps slipping.

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ITER was due to achieve "first plasma" in 2018. Then 2025. Now the project website says that a new timeline will issued soon. Insiders say 2029-31 is a more realistic date.

It may take 10 years to go from first plasma to a fusion reaction that actually generates energy.

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And ITER will only produce thermal energy, not electricity.

If things go well, a DEMOnstration power plant (DEMO) will subsequently be built. It should generate 750 MW of electricity. Equivalent to a small conventional power station.

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But the plans for DEMO are still at an early stage. It was hoped that it would be ready by around 2050, but that is almost certainly unrealistic with the latest delays to ITER.

Perhaps the late 2050s?

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Meanwhile, to keep global warming below 1.5°C  – as the Paris Agreement calls for – emissions need to be cut by 45% by 2030 and reach net zero by 2050.

ITER/DEMO will be too late for that.

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So is fusion power just another white elephant?

Perhaps, but if it does eventually fulfil its promise, it has the potential to produce vast amounts of clean energy.

And the research involved will almost certainly lead to many important scientific discoveries along the way.

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We should make long-term investments, as well ones that bring short-term benefits.

But the promise of fusion power tomorrow mustn't be an excuse to slow investment in renewables and/or nuclear (fission) power today. They are needed now to combat climate change.

ENDS