A new study slated to be published in the Journal of Geophysical Research reports that natural gas producers in the Denver-Julesberg Basin north of Denver are losing 4% of their gas to the air because of leaks and venting.
That lost gas is primarily methane (and a bit of other harmful pollutants, including volatile organic compounds, which contribute to Denver’s smog problem), which of course is not only a valuable product, but a potent greenhouse gas.
How potent? It depends on the time frame. Over a 20 year period, in other words the “short-term,” scientists report that methane has 105 times the heat trapping capacity of carbon dioxide. In the “long-term,” or over 100 years, methane is 33 times more potent than carbon dioxide (this is because methane breaks down over time in the atmosphere, so after 100 years, is less potent).
So what does 4% mean in terms of actual greenhouse gas emissions? Well, just looking at Weld County, which is where the bulk of natural gas development has occurred in the Denver-Julesberg Basin, total production in 2011 was 212,958,693 thousand cubic feet according to the Colorado Oil and Gas Conservation Commission, most of it methane.
4% of 212,958,693 thousand cubic feet is 8,518,347 thousand cubic feet. And using the Environmental Protection Agency’s handy online methane converter, we can calculate that 8,518,347 thousand cubic feet equals 361,689,000 pounds, or 180,840 tons.
Now, greenhouse gases are usually measured in metric tons. So again, using EPA’s handy converter, we can calculate that 180,840 tons of methane equals 164,056 metric tons. That means that just in Weld County, the heart of the Denver-Julesberg Basin, natural gas producers are losing 164,056 metric tons of methane annually.
From a greenhouse gas standpoint, 164,056 metric tons of methane has the same impact as 17,225,880 metric tons of carbon dioxide, at least when considered over a 20 year period. Over a 100 year period, it would equal 5,413,848 metric tons of carbon dioxide.
Regardless of whether one looks at the 20-year or 100-year time-frame, that’s a lot of greenhouse gases.
According to another one of EPA’s handy online calculators, 17,225,880 metric tons of carbon dioxide is the same amount released annually by 3,377,624 passenger vehicles (check out the chart below).
In other words, losing 4% of all produced gas every year in the Denver-Julesberg Basin is like adding more than 3 million vehicles to the road. That’s a potent punch to the climate.
Greenhouse gas emissions from natural gas production in Denver-Julesberg Basin and equivalent number of passenger vehicles.
Of course, this is based on natural gas production just in Weld County. And, as the authors of this latest article point out, their estimates of lost gas don’t include “additional losses in the pipeline and distribution system.”
Is this an indictment of natural gas? Certainly not. But it continues to undermine its reputation as a cleaner alternative to coal, or a “bridge” to renewable energy. It also emphasizes that the greenhouse gas footprint of this “cleaner” fuel may be stomping out the very progress we need to be making in the fight against global warming.