An electrician foreman for the Western Area Power Administration checks a circuit breaker at the Ault Substation in eastern Colorado. The circuit breaker, containing 85 lbs of SF6, protects equipment in the substation against damage from excessive electrical currents | Courtesy of Western Area Power Administration.
Experts are hunting down fugitive carbon emissions from across 20 Energy Department laboratories, sites and program offices — and they’ve already prevented the release of more than 600,000 metric tons of CO2 equivalent since 2009 -- equal to taking 140,000 cars off the road for a year.
These experts are from the Energy Department’s Fugitive Emissions Working Group (FEWG), led by the Office of Health, Safety and Security. They’re working to increase the Energy Department’s sustainability and performance by eliminating energy waste and reducing harmful greenhouse gas emissions.
Fugitive emissions – which are inadvertently released often through valve leaks or breaks – contributed approximately 14 percent of the Energy Department’s Scope 1 and 2 total greenhouse gas emissions in 2008. The most common fugitive emission at Department sites is sulfur hexafluoride (SF6), a nontoxic gas used in electric insulation. In terms of emissions, one pound of SF6 is equivalent to about 11 tons of CO2.
FEWG Chair Josh Silverman remembered, “When we began assessing fugitive emissions within the Department, we were shocked by how much these potent gases expand the DOE’s carbon footprint.”
Through FEWG’s work, between 2008 and 2010, the Energy Department decreased these emissions by 39 percent, on track to a 50 percent reduction by 2012. Over this time period, SF6 emissions were reduced by over 40 percent.
Beyond conducting effective maintenance and repair to reduce leaks, FEWG is deploying technologies to capture and reuse these gases along with finding better alternatives.
For example, Argonne National Laboratory is capturing SF6 gas and reusing it in electron microscopes, accelerators and other high-energy equipment.
Sulfur hexafluoride is also used as a tracer gas for evaluating fume hood performance in laboratories. To minimize releases, Brookhaven National Laboratory (BNL) is testing high-efficiency, low flow hoods with nitrous oxide. So far, BNL has achieved a 98 percent reduction in fugitive emissions by testing fume hoods without SF6.
By driving down fugitive emissions, FEWG’s work has contributed to the Department’s greenhouse gas reduction goal. Recently, the group was recognized with a Secretary’s Achievement Award, the Department’s highest non-monetary honor for a group or team effort.
Still, the work continues. FEWG is now gearing up to reduce emission rates even further over the next two years. Several laboratories plan to install new SF6 capture equipment and expand the use of control technologies.
“We’re going to continue to drive these emissions down as far as we can,” noted Silverman. “Controlling fugitive emissions not only minimizes climate change impacts from Energy Department operations, it’s also the Department’s lowest-cost approach to meeting its GHG reduction goals.”