EDF mapped methane leaks from Google Street View cars

Aging cast-iron and unprotected steel gas mains leak methane continuously, but the gas is invisible, largely odorless once diluted, and escapes underground before reaching the surface in any one obvious spot. Utilities' standard response was to replace pipe based on age and material — the oldest, highest-risk segments first — because that was the only variable they could actually observe at scale; they had no practical way to measure which of thousands of miles of buried pipe was actually leaking the most gas right now.

Replacing pipe by age treats every old segment as equally risky, when in practice leak volume is wildly uneven: a small fraction of leaks account for most of the lost gas, but nobody could tell which fraction without digging up the street. Environmental Defense Fund needed a way to measure the invisible in motion, across entire cities, without excavating anything.

Starting around 2015, EDF fitted specialized methane analyzers to Google Street View cars already driving city streets for mapping, so the vehicles recorded gas concentrations in the air as they passed, block by block. Software then converted those readings into public leak maps showing not just where gas was escaping but roughly how much — letting a utility see its entire buried network's leak profile without excavating a single street.

Fitted methane analyzers to Google Street View cars already driving every street, mapping leak size so crews could rank repairs by actual gas loss, not pipe age.

Google's cars already drove every street, so adding sensors cost far less than a dedicated survey fleet.

Mapping leak volume made the invisible visible, shifting repair priority from pipe age to actual gas loss.

Utilities could concentrate scarce repair budgets on the few leaks causing most methane loss.

When a loss is invisible and uneven, instrument existing infrastructure to measure it directly, rather than rationing fixes by a proxy like age.

The worst leaks cause most of a system's methane loss; the maps let PSE&G and Con Edison target repairs there first, not by pipe age. The project expanded into a dozen-plus US cities in partnership with major gas utilities, and its public leak maps became a reference tool for regulators and city governments deciding where to prioritize pipe-replacement spending, shifting the industry norm from age-based to leak-volume-based repair prioritization.