Part 7, the finale, of the Speculative Design series on human bioenergy. See all parts →
Seven parts ago I introduced a wearable that runs on flatulence and promised it was more serious than it sounded. This is the last stop, so it’s fair to ask where a road that started at a fart reactor actually leads. Speculative design doesn’t predict the future — it sketches a few of them, holds them up, and asks which one we’re walking toward. So here are three.
The hopeful future
In the good version, “harvest, don’t waste” stops being a slogan for power plants and becomes a habit at the scale of a single body.
Nobody is charging a laptop off their own metabolism — you can’t capture nearly enough of it, efficiently or safely, to come close. But the low end of the power budget is real and useful. A pacemaker that never needs a replacement surgery because it sips energy from the heartbeat around it. A remote sensor in a place with no grid, kept alive by the warmth and motion of whoever tends it. A medical patch that monitors a chronic condition and powers itself from the sweat it’s already reading. In this future the body doesn’t run your devices; it quietly tops up the few that are small enough and important enough to matter, and the win is independence — from batteries, from wall sockets, from the maintenance that makes so much medical tech fragile.
Its real payload isn’t the watts. It’s a shift in mindset — the same one the whole series has been circling — where a byproduct stops being waste the moment you look at it as a resource.
The grim future
In the dark version, everything from Part 6 comes true and nothing checks it.
Here the energy was always the cover story. Bodies become always-on inputs — worn under the banner of wellness, safety, or sustainability, reporting continuously to whoever issued the device. Harvesting is “voluntary” the way a workplace badge is voluntary. The data your body produces is owned by everyone but you, priced by insurers, and read by employers. The fart reactor, in this future, isn’t a joke at all; it’s just an honest name for a machine that turns a person into a data source and hands them a little electricity so the arrangement feels fair.
Nothing about this future requires a breakthrough. It only requires that we keep accepting the ordinary version — the trackers, the health apps, the badges — without ever renegotiating the terms.
The boring, likely future
And then there’s the one I’d actually bet on, which is neither.
Human power stays a niche. The “big three” from Part 5 — comfort, efficiency, privacy — turn out to be exactly as stubborn as they looked. The body is a wonderful organism and a terrible battery, and for most jobs a small cheap cell you charge overnight beats anything you could wring out of a person. So human-powered tech survives where it genuinely fits — implants, off-grid sensors, a few clever medical devices, and novelties that make good headlines — and stays out of everywhere it doesn’t. No revolution, no dystopia, just a curiosity that found its handful of honest uses.
If that sounds anticlimactic, it should. Most speculative objects end up here — not adopted, not banned, just quietly instructive.
What the series was actually about
Because the reactor was never really about farts.
It was a lens — an object absurd enough to make you look, aimed at something that was already happening. Under every part of this series was one question: what is the contract between our bodies and our machines? How much energy are we willing to give, how much data are we willing to share, how much discomfort are we willing to wear — and, the question Part 6 insisted on, for whose benefit? The fart reactor just states those terms so plainly, and so ridiculously, that you can’t nod along without noticing them.
That’s the whole trick of speculative design. It doesn’t forecast; it provokes. It builds the ludicrous thing so the ordinary thing sneaking up behind it becomes visible again. You laugh at the wearable that runs on gas, and somewhere in the laugh you remember the five other devices already reading your body for free.
The end of the road
So where does human-powered tech lead us next? Probably not to a world powered by people — the numbers won’t allow it. More likely to a sharper set of questions about consent, ownership, and imagination, dressed up in increasingly clever hardware.
That’s a better destination than it sounds. The future rarely arrives as one big machine. It arrives as a thousand small trades we barely notice making — a little energy here, a little data there — until one day the terms are set. Speculative design is just a way of noticing the trade while there’s still time to argue about it.
Thanks for following the whole strange arc, from taboo to reactor to the ethics of your own exhaust. If it made you look twice at the perfectly normal sensor already strapped to your wrist, the ridiculous machine did its job.
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