A reader writes:
Good piece overall, but I want to point out this sentence: “Brooks Miner adds that ‘natural gas does have a dark side: It is composed primarily of methane, which has a much stronger climate-warming effect than carbon dioxide.'” That’s misleading without context. Methane is, indeed, a potent GHG. But it only has this impact if it is allowed to escape, unburned, directly to the atmosphere. If it is burned completely, it becomes CO2 and water like any other fuel. So the global warming impact of used methane is equal only to its carbon content (which is lower, per unit of energy, than petroleum). It is only leaked methane that has this “dark side” – and since we should be economically averse to wasting fuel through leakage anyway, it’s only a problem when something goes wrong.
The other thing to note is that leaked methane will only circulate for a few decades because it will naturally combust in the atmosphere and degrade to CO2. So while its immediate impact is high, it won’t have the same centuries-long effects as a commensurate amount of carbon emission.
Another goes into greater detail and more:
It’s worth clarifying that the reason we should be worried about natural gas‘ (methane’s) relative radiative forcing is not because of its use in combustion for power generation, but because of potential leaks. When combusted, it leads to fewer emissions per kilowatt-hour than coal. The study Leber quotes found there was no difference between assuming 0% and 3% leakage, so while this is not something we should totally ignore, it’s not likely to have a huge effect.
The item from The New Republic conflates a few different studies, and in my mind, makes the future for natural gas sound more dire than it really is. They cite this study in Environmental Research Letters to say people will increase their usage, and then the EIA chart which shows no decline in coal use. But the finding in the study to which Leber points is much more nuanced.
First, they note that “across a range of climate policies, we find that abundant natural gas decreases use of both coal and renewable energy technologies in the future.” Leber focuses on the decreased renewables, but there is a reduction in the amount of coal used. This is worse than a future in which we go heavy on renewables, but better than a future in which we go heavy on coal.
More importantly, though, is the following from their abstract: “Without a climate policy, overall electricity use also increases as the gas supply increases.” The thrust of that article as I read it, rather than being simply pessimistic about natural gas future, is rather the importance of climate policy in achieving real gains.
And this is where it gets trickier. As the authors of the article note, “Some analysts have noted that natural gas may complement and support variable renewable energy technologies such as wind and solar by providing flexible back-up power that can ramp up quickly. The model we use, MARKAL, is not well-suited to evaluating the potential for this relationship because it does not represent the details of dispatch, unit commitment, and other short-term facets of grid operation.”
As the study that you posted about in July notes, one of the biggest problems that we have going forward is that “the technology we need to succeed may exist, but most of it hasn’t been proven to scale sufficiently.” To meet any sort of goals, we need to figure out a low-carbon baseload resource (nuclear, coal with carbon capture, something) and figure out a way to design the power system to cope with the challenges of high renewable penetration. As page XI in the deep decarbonization report reports, these technologies are still developing. A renewables-only future isn’t yet realistic… the question is, in the short- and long-term, how can we maintain the reliability of the electrical grid and promote the deployment of more renewable technologies while balancing with (very real) concerns concerns about the cost of doing so and continuing worldwide development. I think that natural gas, as part of a broader climate policy, has an important role to play in getting to that future.
By the way, discussion about the promise of solar wouldn’t be complete without a mention of this new energy storage project opened by SoCal Edison recently. These kind of projects will be hugely important for our ability to ramp up the amount of solar and / or wind in our electricity mix, whatever kinds of cost advancements are being made.
(Disclaimer: the US team for the Deep Decarbonization report was mostly my colleagues from my old job. So that provides some of the background from which I draw.)
Update from a reader:
Your reader said that methane leakage is only a problem “when something goes wrong” but studies show it is a large and constant problem with natural gas extraction:
Drilling operations at several natural gas wells in southwestern Pennsylvania released methane into the atmosphere at rates that were 100 to 1,000 times greater than federal regulators had estimated, new research shows.
Using a plane that was specially equipped to measure greenhouse gas emissions in the air, scientists found that drilling activities at seven well pads in the booming Marcellus shale formation emitted 34 grams of methane per second, on average. The Environmental Protection Agency has estimated that such drilling releases between 0.04 grams and 0.30 grams of methane per second. . . .
The researchers determined that the wells leaking the most methane were in the drilling phase, a period that has not been known for high emissions. Experts had thought that methane was more likely to be released during subsequent phases of production, including hydraulic fracturing, well completion or transport through pipelines.
Bill McKibben agrees: “Up to 5 percent of the methane probably leaks out before the gas is finally burned.” Importantly, the livestock industry is responsible for 37% of methane pollution. Anyone who cares about the environment should eat plants.
And another:
I’d like to add some observations about methane’s role as a greenhouse gas. Your post correctly notes that methane has a role as a greenhouse gas only if it is leaked prior to combustion. It’s even more restricted than than that. Its role depends heavily on where the leakage takes place. I suspect the amount of gas that actually ends up in the atmosphere as methane is wildly overestimated.
Methane is highly digestible. It is essentially snack food for a wide variety of bacteria, particularly soil bacteria. The vast majority of natural gas pipes are buried several feet underground, in environments where these bacteria are widespread. Gas leakage which occurs at a slow rate from subsurface piping is very likely to be metabolized by those bacteria (and thus converted to carbon dioxide) before it ever makes it to the ground surface.
There’s an analogy for this that’s widely known in the environmental cleanup business that I work in. Gasoline leakage from subsurface pipes and tanks is a widespread problem. Given the ubiquity of the problem, you would expect to find gasoline vapors (especially the more volatile constituents like benzene) infiltrating into buildings all over the place. But in practice, this infiltration is quite rare. Why? Because soil bacteris eat the vapor-phase benzene before it gets a chance to move up toward the ground surface. By comparison, methane is far easier for bacteria to digest than benzene is, so it is very likely that subsurface methane leaks are not a big issue.
The Dish 