Fusion Foolery

National Ignition Facility at the Lawrence Livermore National Lab

Great. The fusion hype is bad enough already. Now its resurgence is going to interrupt the series of posts I’m in the middle of publishing in order for this post to be “timely.”

The first (and much bigger) round of breathless excitement came in December 2022 when the National Ignition Facility (NIF) at the Lawrence Livermore National Lab (LLNL) announced a (legitimate) breakthrough in achieving fusion: more energy came out of the target than laser energy injected.

At the time, I brushed it off without even reading any articles because I already knew about the NIF’s purpose and limitations, and a few headlines told me everything I needed to know. Who cares how much laser energy went in: how much energy went into creating the laser energy? The laser I used for lunar ranging took 5 kW from the wall plug and delivered 2 W of laser power for a dismal 0.04% efficiency. Such is the cost for shaping ultra-brief pulses: lots of energy is thrown away. The headlines were clearly overblown.

Enough students in my energy class in Spring 2023 asked about the fusion breakthrough (doesn’t that mean we’re done?) that I dug into the details. Even so, I still deemed it unworthy of writing up as a post. But a few days ago, my friend asked me if I was excited about the recent fusion news. I hadn’t heard a peep, but after searching I found a new round of articles based on a second “net gain” laser shot and realized I probably ought to put out a quantitative post on the matter, reminiscent of my blogging origins.

In the end, the NIF fusion accomplishment might be called a stunt.  Stunts explore what we can do (often after an insane amount of preparation, practice, and failure), rather than what’s practical.  Stunts hide the pains and present an appearance of ease and grace, but it’s a show.

Quantitatively, it’s as if you spot a slot machine in a casino that looks very promising. You’re dying to play, because it just feels right—mysteriously appealing to your sense of self. It calls to you. You notice that it takes $2 tokens, but you have none. You go to the window to purchase a token, and are shocked to learn that one $2 token costs $400. Not wanting to look like an uninformed fool, you gulp and buy the token. This slot machine had better live up to its promise! You pull the lever, and surprise! You actually do win! You put in a $2 token and the machine makes very happy noises and flashes lots of lights as it spits out…$3 (and some neutrons, oddly). Queue the headlines! Want to play again?  Actually, this wasn’t your first shot: just the first success after years of trying (but hush!).

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The Alternative Energy Matrix

[An updated treatment of this material appears in Chapter 17 of the Energy and Human Ambitions on a Finite Planet (free) textbook.]

Breathe, Neo. I’ve been running a marathon lately to cover all the major players that may provide viable alternatives to fossil fuels this century. Even though I have not exhausted all possibilities, or covered each topic exhaustively, I am exhausted. So in this post, I will provide a recap of all the schemes discussed thus far, in matrix form. Then Do the Math will shift its focus to more of the “what next” part of the message.

The primary “mission” of late has been to sort possible future energy resources into boxes labeled “abundant,” “potent” (able to support something like a quarter of our present demand if fully developed), and “niche,” which is a polite way to say puny. In the process, I have clarified in my mind that a significant contributor to my concerns about future energy scarcity is not the simple quantitative scorecard. After all, if it were that easy, we’d be rocking along with a collective consensus about our path forward. Some comments have  asked: “If we forget about trying to meet our total demand with one source, could we meet our demand if we add them all up?” Absolutely. In fact, the abundant sources technically need no other complement. So on the abundance score alone, we’re done at solar, for instance. But it’s not that simple, unfortunately. While the quantitative abundance of a resource is key, many other practical concerns enter the fray when trying to anticipate long-term prospects and challenges—usually making up the bulk of the words in prior posts.

For example, it does not much matter that Titan has enormous pools of methane unprotected by any army (that we know of!). The gigantic scale of this resource makes our Earthly fossil fuel allocation a mere speck. But so what? Practical considerations mean we will never grab this energy store. Likewise, some of our terrestrial sources of energy are super-abundant, but just a pain in the butt to access or put to practical use.

In this post, we will summarize the ins and outs of the various prospects. Interpretation will come later. For now, let’s just wrap it all up together.

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Nuclear Fusion

[An updated treatment of some of this material appears in Chapter 15 of the Energy and Human Ambitions on a Finite Planet (free) textbook.]

Ah, fusion. Long promised, both on Do the Math and in real life, fusion is regarded as the ultimate power source—the holy grail—the “arrival” of the human species. Talk of fusion conjures visions of green fields and rainbows and bunny rabbits…and a unicorn too, I hear. But I strike too harsh a tone in my jest. Fusion is indeed a stunningly potent source of energy that falls firmly on the reality side of the science fiction divide—unlike unicorns. Indeed, fusion has been achieved (sub break-even) in the lab, and in the deadliest of bombs. On the flip side, fusion has been actively pursued as the heir-apparent of nuclear fission for over 60 years. We are still decades away from realizing the dream, causing many to wonder exactly what kind of “dream” this is.

Our so-far dashed expectations seem incompatible with our sense of progress. Someone born in 1890 would have seen horses give way to cars, airplanes take to the skies, the invention of radio, television, and computers, development of nuclear fission, and even humans walking on the Moon by the age of 79. Anyone can extrapolate a trajectory, and this trajectory intoned that fusion would arrive any day—along with colonies on Mars. Yet we can no longer buy a ticket to cross the Atlantic at supersonic speeds, and the U.S. does not have a human space launch capability any more. Even so, fusion remains “just around the corner” in many minds.

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Warm and Fuzzy on Geothermal?

[An updated treatment of some of this material appears in Chapter 16 of the Energy and Human Ambitions on a Finite Planet (free) textbook.]

The Earth started its existence as a red-hot rock, and has been cooling ever since. It’s still quite toasty in the core, and will remain so for billions of years, yet. Cooling implies a flow of heat, and where heat flows, the possibility exists of capturing useful energy. Geysers and volcanoes are obvious manifestations of geothermal energy, but what role can it play toward satisfying our current global demand? Following the recent theme of Do the Math, we will put geothermal in one of three boxes labeled abundant, potent, or niche (puny). Have any guesses?

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Nuclear Options

[An updated treatment of this material appears in Chapter 15 of the Energy and Human Ambitions on a Finite Planet (free) textbook.]

simpsons.wikia.com

A recent thrust on Do the Math has been to sort our renewable energy options into “abundant,” “potent,” and “niche” boxes. This is a reflection of my own mathy introduction to the energy scene, the result of which convinced me that we face giant—and ultimately insurmountable—hurdles in our quest to continue a growth trajectory. It is not obvious that we will even manage to maintain today’s energy standards. We have many more sources/topics to cover before moving on to the “now what” phase of Do the Math. Meanwhile, requests for me to address the nuclear story are mounting. So before readers become mutinous, I should interrupt the renewable thread to present my nuclear reaction. It’s a rich topic, and in this post I will only give a tutorial introduction and my big-picture take. A single post can’t possibly address all the nuances, so my main goal here is to demystify what nuclear is all about, build a vocabulary, and set a foundation for further discussion in later posts.

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