In 2015, a storage facility near Los Angeles experienced a blowout. More than 10,000 tons of natural gas was released. . For responders, that created a problem. Natural gas is invisible and tracking just when the gas was dissipating and where it was going proved to be a challenge. The incident inspired a team of researchers at the University of Colorado Boulder to make that process easier.
The university has secured a $1.3-million grant to explore how lasers may better detect gas leaks from facilities like the one in California. After gas is extracted from remote, rural areas, it’s stored near cities at high pressures in underground reservoirs and caverns. If a blowout occurs, it can pose a significant risk to nearby communities.
Greg Rieker is an assistant professor of mechanical engineering at CU Boulder. His engineering team is working with the National Institute of Standards and Technology to refine a laser system that’s able to measure changes in methane concentrations in the air down to one part per billion, the equivalent of a single drop of water in an Olympic sized pool. He says think of the laser as radar for tracking gas.
“It’s akin to a methane radar, essentially, so we use a centralized laser system
that sends out beams over long paths, and then we can use those laser beams,” Rieker said. “We are looking for absorption on the laser beam by methane, and we can detect that absorption, and relate that back to how much methane was in the path of the laser beam. And so we send these beams out in many different directions. We take measurements of the concentrations of methane, as a function of wind, and we can determine from the wind direction and the measured concentrations where a leak source is, and how big a leak source is. So, it’s both location and sizing of the leak.”
Right now, the prototype resides in a 16-foot trailer.. On top of that trailer, there’s a small telescope. The laser beam distance has a range of 1 to 2 miles, depending on the terrain.
The main difference between this technology and current methods for detecting large scale gas leaks is that current methods rely primarily on infrared cameras. Using this method means the field operators need to be fairly close to a leak when it is active.
Rieker: “The problem is, that’s very expensive, and you have a lot of worker time involved in that, they have to go to each site, and so they spend a lot of time looking at nothing in order to find the leak. This system is automated, so we would leave it in a particular location for a few weeks, so that we can see many different wind conditions.”
Scientists then analyze the data and are able to more accurately react to gauge
how large and how widespread a certain leak may be. Rieker says this method will be more cost effective for gas companies.
“One of the things that I think is important to note about this, is we’re trying to work together with companies, not against them,” he said. “We didn’t want to feel like an adversary to these companies, we’re really trying to come up with a low cost way for them to keep the methane in the ground until we are ready to use it.”
The team will share results of the study with the Environmental Protection Agency for inclusion in its greenhouse gas emissions inventory.
