Nuclear Fusion? Not in my lifetime!

I love science fiction, it’s my favourite genre and nuclear fusion is one of its technological staples. In novels, fusion powers everything from cities to spaceships, a source of clean energy whose only fuel is water, and whose waste is rarely discussed, let alone handled.

But that’s science fiction. Down here on planet earth, the closest we get to nuclear fusion is using the second-hand effects of sunlight by way of burning hydrocarbons, or my preferred option, photovoltaic cells. That’s because generating electricity from nuclear fusion literally means we have to make – and keep – a miniature star in a bottle.

If that sounds hard, you’re right. The basic idea is not that complicated, but the engineering and materials science involved are staggering, which is why nuclear fusion has been one of those “next decade” technologies for the last five decades.

And sadly, despite the enduring hype, I don’t see that changing in my lifetime.

But let’s go back to the beginning, which is 1920 when Einstein's now famous E=mc2 equation prompted Arthur Eddington to propose that nuclear fusion powers the sun. Fusion was demonstrated in 1932 and the first nuclear fusion bomb was let off in 1952. A working fusion reactor never followed.

Compare that to nuclear fission, which was first observed in 1938 and the first nuclear fission bomb was let off in 1945. The X-10 Graphite Reactor generated electricity in 1948 and the “nuclear energy” industry was born.

Watch enough The Simpson’s and you’ll be suitably informed of the pitfalls of nuclear power plants. Think very long-lived radioactive waste, weaponised plutonium, the need for a highly trained, highly diligent workforce, and unfortunately of course, the potential for catastrophic meltdown. We’ve lived through these – Three Mile Island in the States, Chernobyl in the Ukraine, and Fukushima in Japan – and the devastation caused is widespread and tragic.

Given the choice of global warming from burning hydrocarbons, meltdowns, and radioactive waste of nuclear fission, or the clean energy of nuclear fusion, it’s a no-brainer. Fusion wins big.

But timing is everything and I feel nuclear fusion will remain perpetually over the horizon because it’s literally missed the boat in terms of energy generation (with one caveat that I’ll get to right at the end).

Why do we care about nuclear fusion anyway?

Calculating the ‘E’ aspect of Einstein's equation dramatically answers this question.

Convert a kilogram of anything via mc2 and you generate a smidge under 90,000,000,000,000,000 joules of energy. It’s a stupendous amount of power, enough to light a 100-watt bulb for 28 million years! Or more practically, power two hundred thousand American homes for a year.

Chemical energy is nowhere near as efficient. A 140-kilogram barrel of oil generates a paltry-by-comparison 5,861,520,000 joules. It might look like a big enough number, but you’d need 15 million odd barrels to power those homes. In practice, it’s way more barrels though; converting oil to electricity and distributing it to households is not anything like 100% efficient.

Still, the point is made. Fusion is so dramatically more efficient that getting it right would be a game changer in terms of energy generation.

So why don’t we have it already?

Remember that ‘star in a bottle’ description? That’s pretty much the reason we don’t have nuclear fusion power generation.

Here are some specs for the International Thermonuclear Experimental Reactor (ITER), which is under construction in France:

• Involves around 800 scientists
• Operates at some 150 million degrees Celsius
• Is a global effort with sponsors in 35 countries
• Comprises 1 million parts
• Full power output is expected around 2035

Oh, and it’s costing a lazy 30 billion Australia dollars! That’s billion with a ‘b’, as they say on the telly.

Check the name of this again, it’s an experimental reactor. It’s not a working power plant. It’s not a working prototype. It’s basically a “Let’s see if we can even do this” device. And the main reason this is experimental is the 150 million degrees part. That’s considerably hotter than the surface of the sun. Indeed, probably the only thing that is routinely used with comparable temperatures is a plasma cutter. But that’s still only 25,000 degrees Celsius so it’s hot but not as hot as nuclear fusion. Oh, and it’s used to…cut things! The core of a working nuclear fusion reactor will be a 100 million degree or more plasma. Basically, scientists are trying to bottle up a cutting torch and somehow keep it bottled up while they siphon off the heat to drive a turbine to generate electricity. That’s some tricky engineering.

Paolo Frankl, of the International Energy Agency, has said in support of ITER that the world does not “have the luxury of avoiding any option” in ensuring power supplies. And in the global scheme of things, $30B is not that much money. There are numerous renewable energy projects costing many billions, including the Asian Renewable Energy Hub (AREH), but the difference is those are doable projects. We really don’t know if ITER is even doable.

Of course, ITER is not the only nuclear fusion game in town. A number of other government projects are running, and startups have entered the field, but that does not change the engineering difficulty in taming a 100-million-degree plasma torch and converting it into useable electricity.

What’s the upside if we get this right?

Fusion power has numerous advantages besides energy efficiency. It is not renewable, but fuel is so abundant that our species is more likely to go extinct than run out of it. Operationally, fusion plants produce zero carbon emissions, so will not contribute to global warming. And as we know from current experiments, the plasma is inherently unstable so any loss of power or physical damage to the plant – from an earthquake, say – will not trigger a meltdown. Instead, the plasma will essentially lose shape and snuff itself out.

About the only downside of nuclear fusion, apart from that we can’t get it to actually work, is that it creates radioactive waste. They are nowhere as long-lived as nuclear fission wastes, to be fair, but still must be dealt with on the timescale of decades to a century.

What’s the catch?

OK, here’s the thing. Fusion would be awesome. Absolutely. But I think that batteries, whether lithium ion or one of the emerging technologies such as vanadium redox or zinc air, are going to overtake both our need for fusion power, and the economic necessity of solving it. Take grid scale banks of PV, wind farms, and pumped hydro, include onsite generation in the form of domestic and commercial scale solar panels, connect batteries to everything, throw in demand response, and within fifteen years, fusion is moot.

Just as investments in new coal and gas fired power plants are falling off a cliff, investments in fusion will do the same. Reactors like ITER are too impractical, too expensive, and too hard to deal with. But solar batteries, powered by the biggest fusion reactor around, well that’s not impractical, it’s not expensive, and it’s not hard to deal with. Unlike my beloved science fiction novels, our future isn’t tokamak’s and tritium pellets. It’s solar batteries and other renewables. Fusion is dead, long live fusion.

Caveat…

Fusion is a dead end…unless we go off planet. Then fusion makes a lot of sense. Power a moon colony from a fusion reactor. Terrific, fire it up and let’s go. Mars base anyone? Here’s the fusion reactor to keep everyone warm and those iPads running. Fusion for space colonisation makes a lot of sense, and that’s the only economic motivation I can see working out. And if I lived to see that, well, that would be something.