Sound is a terrible fuel, and that is the awkward starting point for any city that wants to live on screams. A loud human scream carries an acoustic intensity roughly comparable to street traffic, and basic acoustics shows that even in a packed building the total sound power adds up to only tiny fractions of what a single kitchen appliance draws.
Engineers would need to cheat. Hard. Instead of bare ears and air, a scream city would trap sound in highly reflective chambers, compress it with horn‑shaped ducts, and focus it onto dense arrays of piezoelectric transducers. Those devices, already used in ultrasound and sonar, convert rapid pressure oscillations into electric potential through the piezoelectric effect, but their conversion efficiency for audible sound is low, so almost the entire architecture would chase one goal: prevent acoustic energy from leaking away as heat.
The brutal math refuses to blink. Even with ideal impedance matching, high‑gain acoustic waveguides and optimistic transducer efficiency, the energy a child delivers in several seconds of screaming barely rivals the chemical energy in a mouthful of food. To power a single urban block, a grid‑scale facility would need either impossible acoustic intensities that approach structural damage thresholds or impossible numbers of children, backed by massive storage systems such as flywheels or electrochemical batteries to smooth the spiky, intermittent output. A scream‑driven metropolis, taken literally, is less an engineering blueprint than a reminder of how extravagantly dense conventional fuels and electrochemical cells already are.
