Move over mobile mapping cars. There’s a new high-tech vehicle in town and it’s cruising through neighborhoods on a mission to spot methane gas leaks and reduce fugitive emissions.
Unitil, a provider of electricity and natural gas to customers in New England, is deploying a special vehicle equipped with an Advanced Mobile Leak Detection (AMLD) system to all of its natural gas service territories in an effort to more efficiently and accurately identify and measure fugitive emissions, which are the accidental release of gas, primarily methane, into the atmosphere.
Launched as a pilot program in its Massachusetts service area in 2023, Unitil has now expanded the AMLD surveying to Maine and New Hampshire as well to cover the company’s entire gas distribution network. The company starts using the vehicle in early spring and operates into the fall months during nighttime hours only.
“The results of this successful pilot program provided valuable insight into our natural gas distribution system and we believe this highly advanced detection equipment will improve our ability to more accurately measure leaks and prioritize and address the biggest emitters sooner. This AMLD system is much more advanced than other leak detection equipment and will become a critical resource as we continue our efforts to minimize fugitive emissions,” Unitil External Affairs Director Alec O’Meara said.
The innovative program involves the use of a newly purchased Ford Escape equipped with cutting-edge technology provided by Picarro – an industry leader in AMLD systems. The vehicle features sensor devices and software that can detect, monitor, and mitigate methane gas leaks. Key data is collected when the vehicle is simply driven along streets in areas where Unitil’s gas distribution systems are located. The front of the vehicle includes four sampling ports and a vacuum pump, which draws the air sample from the front to the back. The air is then pumped into a chamber, which uses laser technology to provide data to indicate whether gas is present. An anemometer is also installed on the vehicle to measure wind speed and direction.
The AMLD system, which has a low minimum detection limit, provides the location of a leak and leak rate – from hundreds of feet away in some instances – and can help reduce methane emissions by quickly providing precise leak detection information across the entire distribution gas system, resulting in prompt mitigation and a more accurate measure of the system’s actual emissions rate.
Before this new technology, Unitil did not have a method for performing direct measurements of fugitive emission rates related to its natural gas infrastructure. The AMLD survey work has shown that Unitil’s gas distribution system had significantly lower fugitive emissions than the company had previously estimated by using other factors for its calculations. According to the results, there was a 96% reduction in actual fugitive emissions from the company’s gas system in Massachusetts, an 84% reduction in Maine, and a 90% reduction in New Hampshire.
Based on the results, which have accurately identified sources of leaks and their associated flow rate, Unitil also found that approximately 36% of the total emissions came from only 11% of the leaks. The company was able to immediately address those larger leaks and quickly reduce fugitive emissions.
More information on Unitil’s AMLD system can be found in the company’s 2025 Corporate Sustainability & Responsibility Report by visiting unitil.com/reports/2025-Sustainability-Report.
