A LONE robot trundles through an old landfill in central Sweden, shooting out a laser beam. Nicknamed Gasbot, its job is to hunt down methane leaks in the vicinity. Machines like this one could one day be used to sniff out dangerous emissions in landfills, mines and even city streets.
Methane leaks are worrying – they can cause explosions as well as contributing to global warming. One study released earlier this year found that researchers consistently underestimate methane levels in the atmosphere, partly because of hard-to-detect leaks.
"You have more methane than you know about. You have sources that you don't know are there," says Achim Lilienthal, who heads the Gasbot project at Örebro University in Sweden. "To find this methane is a very important task."
Gasbot travels along a predetermined path, shooting out a laser about 30 metres ahead. The beam is tuned to a specific wavelength that tends to be absorbed by the gas molecules they are looking for, in this case methane. When the beam reflects back, Gasbot's sensors calculate how much of it was absorbed, building a map of methane concentration and distribution in its environment. Tests at the landfill showed that the robot could detect methane at concentrations of 5 parts per million in the air. It also sniffed out an artificial leak planted by the researchers. Gasbot was presented at a robotics conference in Hong Kong this week.
Later this year, Gasbot will be sent into a local steel foundry, with its sensors adjusted to search for hazardous substances like nitrous oxide and lead and quartz dust.
There are plans to try Gasbot in an underground tunnel in Austria, and a Swedish lake where methane bubbles up through the ice. Lilienthal is also considering adapting the technology for drones.
"This would be a good solution, especially for unknown and potentially hazardous environments or terrain," says Nathan Phillips of Boston University. Looking for methane leaks is important, particularly with the growth of fracking. Last week, the UK's National Physical Laboratory unveiled a truck mounted with a lidar system to look for leaks from landfills and oil refineries. The NPL is now working with Cuadrilla, one of the leading fracking firms, to test for methane leaks at its sites.
This article appeared in print under the headline "Methane leak? This is a job for Gasbot"
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