Part 6 of the Speculative Design series on human bioenergy. See all parts →
We started this series with a joke — a wearable “fart reactor” — and kept following it into less funny territory. We asked why you might harness the body, how a device might work, what it would do to social norms, what other bodily outputs could power, and which design challenges stand in the way. One question has been waiting under all of them, and it is the one I promised back in Part 2 and kept postponing: if your body becomes a power source, who actually benefits — and who owns what it produces?
The honest answer is that the electricity was never the point.
The output that matters isn’t the energy
A device strapped to your body to capture gas, or sweat, or motion produces two things. One is a trickle of power — microwatts, maybe milliwatts, rarely enough to matter. The other is a continuous, intimate stream of data about your body: gas composition that hints at your diet and gut health, sweat chemistry that reveals hydration, stress, and blood markers, motion and heat signatures that map your day.
Weigh those two outputs and it isn’t close. The energy is a rounding error. The data is the asset. Any company that built a body-powered device and wasn’t interested in the data stream would be leaving the valuable half of the machine switched off — and companies rarely do that.
So the speculative question sharpens. It isn’t “should we harvest energy from the body?” It’s “when we do, who ends up holding the record of what the body did?”
Following the benefit
It helps to trace who gains at each layer, because the discomfort and the reward rarely land on the same person.
- You wear the thing. You supply the raw material, absorb the discomfort, and carry the exposure. In return you get a little power and, if you’re lucky, some health insight.
- The manufacturer gets a subscription-shaped relationship with your biology — a sensor that reports continuously, long after the novelty of “charging your watch with your body” wears off.
- Your employer or insurer is the layer that should worry you most. A wearable justified as wellness or safety is also a monitor. We already have the preview: sensors marketed to protect workers from heat stress double as tools that track where a body is, how hard it’s working, and when it falters. The safety framing is real. So is the surveillance.
This asymmetry isn’t hypothetical or unique to speculative gadgets. It’s the pattern every body-adjacent technology has already walked through. Step counters became insurance inputs. Period-tracking apps became evidence. A spit-in-a-tube ancestry kit became, when the company behind it hit hard times, a database of millions of people’s genomes looking for a buyer. In each case the pitch was personal benefit and the durable value turned out to be the data — held by someone else.
Ownership is the unsolved part
We have decent language for who owns a song or a house. We have almost none for who owns the exhaust of a living body.
The law is patchy and jurisdictional. A few places treat biometric data as special — Illinois’s biometric privacy act lets people sue over its misuse; the EU’s data-protection rules treat biometric and health data as a special category with extra restrictions on how it can be processed. Most of the world has neither. And “consent,” in practice, is a checkbox at setup that nobody reads and no one can meaningfully refuse if the device is a condition of a job.
The principles that would make this fair aren’t exotic. Data from the body should default to the person the body belongs to. Harvesting energy shouldn’t be a trojan horse for collecting a health record. Consent has to be real — revocable, legible, and not coerced by employment. What’s missing isn’t the ideas. It’s any obligation to follow them.
Why the absurd version is useful
Here is where the fart reactor earns its keep. It’s ridiculous on purpose, and the ridiculousness is a solvent — it dissolves the reflex to accept.
Nobody would sign away ownership of their intestinal gas data to a corporation without laughing. But state the same deal in the sober vocabulary of steps, heart rate, sleep stages, and location, and hundreds of millions of people have already signed it. The joke isn’t that a fart reactor is far-fetched. The joke is that we’ve quietly agreed to the serious version and only notice the terms when someone makes them silly enough to see.
That’s what speculative design does at its best: it builds the absurd object so the ordinary arrangement becomes visible again.
Where this leaves us
If we ever do harvest power from human bodies at scale, the engineering will be the easy part. The hard part is the contract — how much of ourselves we hand over, on what terms, and to whom the record belongs when the lights are off. Get the ownership wrong and “human-powered” stops meaning powered by humans and starts meaning powered on humans.
That contract — the trade of energy, data, and comfort, and who it’s really for — is the thread the whole series has been pulling. In the final part, I want to follow it forward: where human-powered technology could actually go, in the hopeful version, the grim version, and the boring-but-likely one in between.
Next: Part 7 — Speculative Futures: Where human-powered tech could lead us next →
References
- AP News, Sensors can read your sweat and predict overheating. Here’s why privacy advocates care
- Illinois Biometric Information Privacy Act (BIPA), 740 ILCS 14
- EU General Data Protection Regulation, Article 9 (special categories of personal data)
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