Google Street View vehicles are doing more than mapping city streets. Colorado State University researchers equipped three of these cars with advanced infrared laser methane analyzers to pinpoint leaking underground natural gas lines.

This approach is far quicker and more effective than conventional ways of detecting leaks, and could help reduce emissions of the potent greenhouse gas by identifying where infrastructure repairs are needed. A chief motivation of the project is to help utility companies and governments prioritize leak repairs based on the magnitude of emissions. The researchers calculate that fixing the largest 8% of leaks would cut pipeline methane emissions by 30%.

Google Street View cars with methane sensors detect leaks under city streets. (Source: Colorado State University)

These mobile instruments identify plumes of methane gas in real time, without the need for a gas chromatography analysis in the lab. A set of algorithms and protocols provides accurate accounting of methane leaks, including the size of the plumes. Methods have also been developed to filter out false positive readings, such as those associated with a wayward reading from a landfill or nearby power facility.

Leak maps have been generated for Boston, MA; Burlington, VT; Chicago, IL; Dallas, TX; Indianapolis, IN; Jacksonville, FL; Los Angeles, CA; Mesa, AZ; Pittsburgh, PA; Staten Island, NY; and Syracuse, NY. The New Jersey utility company PSE&G has approved almost $1 billion worth of upgrades directed in part by the research data.

Cities with aging, corrosion-prone distribution lines – such as Boston, Staten Island, and Syracuse -- had leaks that released 25 times more methane per kilometer of road (2 liters of methane per minute per kilometer) than Burlington and Indianapolis (0.08 liters of methane per minute per kilometer).

The non-profit Environmental Defense Fund and Google Earth Outreach are also partners in this research.