By Zeke Hausfather
For the past century, coal has been king, providing the majority of U.S. energy for electricity generation.
But a combination of new federal and state environmental policies and a glut of cheap natural gas (mostly from hydraulic fracturing or fracking) have led to a dramatic shift during the past decade, with coal dropping from 50 percent to 32 percent of our electricity generation and gas increasing from 18 percent to 33 percent.
Just under a third of existing coal-based power generation in the U.S. has been shut down and the Obama administration has aggressively embraced the replacement of coal with gas as a key part of meeting its 2030 climate targets. We are quickly traveling down a gas bridge away from coal. But will this shift actually be a good thing for the climate?
Slashing Emissions at the Plant
At first glance, replacing coal with natural gas seems like a good (though not great) step in combating climate change.
Overall, carbon dioxide emissions from new gas power plants are as much as 66 percent lower than those of existing coal power plants. About half of this reduction is due to differing carbon intensities of the fuels (natural gas emits 40 percent less carbon than coal per unit of heat). The other half is due to the higher generation efficiency of natural gas (new natural gas plants convert heat to power at upwards of 50 percent efficiency, while typical coal plants only operate at about 33 percent efficiency).
A way to reduce emissions by as much as two thirds while also saving money seems like a no-brainer for climate policy. But natural gas has an Achilles' heel that makes the question much harder to answer.
Direct CO2 emissions from electricity generation in grams per kWh. Based on calculations from Hausfather 2015.
Natural gas is predominately composed of methane. When methane is burned to produce electricity or heat, it releases carbon dioxide and water vapor.
But not all natural gas produced is burned. Some of it is leaked at gas wells, in compressor stations, from pipelines or in storage. Methane is a powerful but short-lived greenhouse gas. While it is in the atmosphere, it is around 120 times more powerful than carbon dioxide per ton, but it quickly decomposes through chemical reactions and only about 20 percent of the methane emitted today will remain after 20 years.
Carbon dioxide, on the other hand, has a much longer atmospheric lifetime. About half of the carbon dioxide emitted today will be around in 100 years (and virtually none of the methane will be) and about 15 percent of today's carbon dioxide will still be in the atmosphere in 10,000 years.
This difference in longevity makes a comparison between the two tricky. Essentially, how much methane emissions today matter for the climate depends largely on the timeframe you are considering. If you care about avoiding warming later in the century (as the United Nations does with its 2C warming by 2100 target), there is relatively little problem with short-term methane emissions, as long as they are phased out in the next few decades. If you care about short-term changes, however, methane is a much bigger deal.
How much methane leaks from the natural gas system is very much an open question. For a long time official U.S. Environmental Protection Agency (EPA) numbers suggested the emissions were small and falling fast, only amounting to around 1.5 percent of total production.
But dozens of independent academics doing research using aircraft, satellite data and other instruments have consistently found higher emissions than officially reported.
Adam Brandt at Stanford University published a high-profile paper in the journal Science in 2014 summarizing all the research to date. He found that overall emissions were likely between 25 and 75 percent higher than reported by EPA, suggesting that actual natural gas leakage rates are probably somewhere between 2 and 4 percent of gas production. (Some researchers have found leakage as high as 10 percent for individual fields, but there isn't evidence that those findings are characteristic of the sector as a whole).
How Much Do Leaks Matter?
What do these leakage rates mean for the viability of natural gas as a bridge fuel? Again, it comes down to a question of time frame.
Let's look at a simple example of a big coal power plant. One option is to leave it alone for the next 30 years, at which point it will be replaced by renewable energy.
Another option is to replace it with gas today and replace that gas with renewables in 30 years.
The figure below shows the climate impacts over time (measured in units called radiative forcing) of existing coal (the dashed black line), new high-efficient coal plants (the solid black line) and new gas plants (the green line). The potential range of natural gas leakage is expressed by the gray envelope around the green line, with 1 percent leakage at the bottom and 6 percent leakage at the top (the green line itself shows a 3 percent leakage case).
Adapted from Figure 3 of Hausfather 2015.
If leakage is higher than 3 percent, there are some periods in the next 30 years when gas will result in more climate impact than new coal plants. If leakage is higher than 4 percent, there are some periods when gas will be worse for the climate than existing coal plants.
But no matter what the leakage rate is, gas will still cut the climate impact by 50 percent in 2100 compared to new coal and 66 percent compared to existing coal. So whether switching from coal to gas is beneficial in this simple example depends on how you value near-term or longer-term warming.
The importance of near-term warming is tough to assess. Climate models, by and large, don't predict any irreversible changes in periods as short as 30 years and potential tipping points in the climate generally depend more on the peak warming that occurs (which in nearly all foreseeable cases would occur after 2050).
But there is much about the Earth's climate that is still unknown and scientists can't categorically rule out the potential for shorter-term warming to cause unforeseen impacts.
With longer-term warming, the impacts are much more clear (and generally more dire). By the end of the century, we'd expect around 4C warming in a world where we didn't take any action to slow emissions. As the damages of climate change tend to increase exponentially with rising temperatures, many economists argue that the biggest impacts of climate change will occur later in the century and that the main focus should be on reducing longer-term warming.
What About Choosing Neither Coal Nor Natural Gas?
There is yet another wrinkle in the comparison of gas and coal. If they were the only two ways we could generate electricity, the analysis would be fairly straightforward.
But there are many zero or near-zero carbon energy sources that are preferable to both coal and gas, including wind, solar and nuclear power. In a perfect world, we would skip the gas bridge entirely and immediately replace all the coal plants with renewables.
The challenge is that although renewables are increasingly cost competitive with coal in some parts of the country, on average, they are still more expensive. Renewables are also often intermittent, producing less power when the sun doesn't shine or the wind doesn't blow and incurring additional expenses for energy storage technologies to help balance out the grid, at least once renewables reach a high enough percent of generation.
On the other hand, renewables are getting cheaper and although it might not be practical to replace all coal plants with renewables immediately, it's definitely possible to do so in the next decade if renewables continue to fall in price. If we replace coal with gas today, we've sunk costs into new gas infrastructure that we might be loath to replace a few years later with renewables. In this way, a gas bridge could delay the widespread adoption of renewables.
It comes down to this: If we think that coal plants would stick around for 15 years or more in the absence of gas, its probably better to replace them with gas today. If we think we will have the political will to retire gas plants early, we could also potentially benefit from a gas bridge.
But if we end up locking in gas infrastructure that sticks around and delays renewables, we might be better off eschewing a gas bridge even if it means sticking around with coal a bit longer.
It's a tough problem with no simple answers, but the one thing we know for sure is that if natural gas is to serve as a bridge away from coal, it had better be a short one.
EcoWatch Daily Newsletter
As protests are taking place across our nation in response to the killing of George Floyd, we want to acknowledge the importance of this protest and the Black Lives Matter movement. Over the years, we've aimed to be sensitive and prioritize stories that highlight the intersection between racial and environmental injustice. From our years of covering the environment, we know that too often marginalized communities around the world are disproportionately affected by environmental crises.
- Lead Poisoning Reveals Environmental Racism in the US - EcoWatch ›
- First-of-Its-Kind Study Finds Racial Gap Between Who Causes Air ... ›
- Pollution, Race and the Search for Justice - EcoWatch ›
By Peter Beech
Using waste food to farm insects as fish food and high-tech real-time water quality monitoring: innovations that could help change global aquaculture, were showcased at the World Economic Forum's Virtual Ocean Dialogues 2020.
Fly fishing. nextProtein
BiOceanOr's AquaREAL system. BiOceanOr
- Environmental Innovation Will Transform Business as Usual ... ›
- How an Army of Ocean Farmers Is Starting an Economic Revolution ... ›
The big three broadcast channels failed to cover the disproportionate impacts of extreme weather on low-income communities or communities of color during their primetime coverage of seven hurricanes and one tropical storm over three years, a Media Matters for America analysis revealed.
Researchers at the pharmaceutical giant Eli Lilly announced yesterday that it will start a trial on a new drug designed specifically for COVID-19, a milestone in the race to stop the infectious disease, according to STAT News.
- Dogs Can Smell COVID-19 - EcoWatch ›
- Drugs Touted by Trump for COVID-19 Increase Heart Risks, Studies ... ›
- Coronavirus Vaccine Candidate Shows Promise in Mice - EcoWatch ›
The sixth mass extinction is here, and it's speeding up.
Terrestrial vertebrates on the brink (i.e., with 1,000 or fewer individuals) include species such as (A) Sumatran rhino (Dicerorhinus sumatrensis; image credit: Rhett A. Butler [photographer]), (B) Clarion island wren (Troglodytes tanneri; image credit: Claudio Contreras Koob [photographer]), (C) Española Giant Tortoise (Chelonoidis hoodensis; image credit: G.C.), and (D) Harlequin frog (Atelopus varius; the population size of the species is unknown but it is estimated at less than 1,000; image credit: G.C.).
- Humanity 'Sleepwalking Towards the Edge of a Cliff': 60% of Earth's ... ›
- New Border Wall Construction Threatens 8 Species With Extinction ... ›
- The Insect Apocalypse Is Coming: Here Are 5 Lessons We Must Learn ›
By Cathy Cassata
With more than 1.7 million confirmed cases of COVID-19 in the United States and more than 100,000 deaths from the virus, physicians face unprecedented challenges in their efforts to keep Americans safe.
They also encounter what some call an "infodemic," an outbreak of misinformation that's making it more difficult to treat patients.
When Leaders and Doctors Spread Misinformation<p>When people in charge of towns, cities, states, and countries spread misinformation, the potential for belief in misinformation to result in policies can have harmful effects.</p><p><a href="https://www.northwell.edu/find-care/find-a-doctor?q=Bruce+E.+Hirsch%2C+MD&insurance=&location=&query_type=provider&physician_partners=false&default_view=list&gender=&language=&sort=relevancy" target="_blank">Dr. Bruce E. Hirsch</a>, attending physician and assistant professor in the infectious disease division of Northwell Health in Manhasset, New York, says an example of this is when President Trump informed the public he was taking hydroxychloroquine as a preventive measure.</p><p>"To approach this enormous challenge, we need some intellectual honesty and clarity, and to disregard expertise and to make decisions and model decisions based on hunches is inviting us to handle challenges on the basis of rumor and uninformed opinion. The magnitude of that error is epic," Hirsch told Healthline.</p><p>Stukus agrees, noting that the harm of this proclamation is documented.</p><p>"Early on when the president touted the benefits of hydroxychloroquine and azithromycin, people started to hoard this medicine, and state boards had to shut it down because they were getting so many prescriptions for this unproven therapy that it was not available for those who truly needed it, such as those who have lupus and autoimmune conditions," Stukus said.</p><p>He adds that calls to poison control centers increased after the president suggested using disinfectant to prevent contracting the new coronavirus.</p>
Listen to Science, Even When it Changes<p>When recommendations change or evidence flip-flops, skepticism may arise. However, Stukus says change is the beauty of science.</p><p>"That shows us that we can evolve, and if the evidence shows that our prior thoughts were incorrect, we need to be able to change our recommendations and advice based upon the best quality of evidence at the time," he said.</p><p>Pierre agrees.</p><p>"Science is an iterative process, whereby we arrive at facts and truth through repeated and controlled observations. That means that it's inherently self-correcting as we revise conclusions based on ongoing research. Scientific facts aren't immutable dogma chiseled on a tablet. They change based on the best available evidence we have at a given point in time," he said.</p><p>Because research of COVID-19 has only been underway for 6 months, information is evolving rapidly, and new information may contradict old.</p><p>"There's still much we don't know about exactly how [COVID-19] spreads, what effects it has on the body, or how to best treat it. That means that the best available evidence is preliminary, but that doesn't mean that we should ignore it or turn to other sources of information or opinion as if they're just as valid," Pierre said.</p><p>He explains that conspiracy theories based on mistrust lead to vulnerability to misinformation.</p><p>If people mistrust science because it sometimes "changes its mind," Pierre said, "that shouldn't be used to embrace other opinions based on no evidence at all, which are typically selected based on confirmation bias: what we want to believe rather than what the objective evidence supports."</p>
Where to Find the Best Information<p>Stukus says to start with the <a href="https://www.cdc.gov/coronavirus/2019-nCoV/index.html" target="_blank">CDC</a> and <a href="https://www.nih.gov/health-information/coronavirus" target="_blank">NIH</a>. Then check with your local health officials, because COVID-19 guidelines may vary depending on where you live.</p><p>If you can't find information you need or have questions specifically related to you, call your primary care doctor.</p><p>"Your personal doctor should always be a resource for individual specific questions because they know best how to apply all the nuances retaining to your health, and how to incorporate all the other general [COVID-19] recommendations," Stukus said.</p><p><a href="https://www.eehealth.org/find-a-doctor/b/boyd-laura-b/" target="_blank">Dr. Laura Boyd</a>, primary care physician at Edward-Elmhurst Health Center in Elmhurst, Illinois, says her clinic receives a lot of calls about COVID-19.</p><p>"Most doctors' offices are receiving calls and answering questions, and doing phone or video visits to help clarify and/or order testing over the phone based on patients' symptoms. It is always best to call your doctor's office first instead of worrying about symptoms and waiting too long to seek treatment," she told Healthline.</p><p>If your primary care doctor has limited testing, she suggests looking on your state's public health website for available testing sites.</p><p>With a lot of unknowns related to this virus and disease, Boyd says many patients are feeling overwhelmed and anxious for a treatment.</p><p>"Unfortunately, there is no specific medication recommended for COVID for outpatient. There are a lot of ongoing studies with various drugs going on within the hospital setting. Patients should always contact their doctors about their specific symptoms as they can treat the symptoms that go along with COVID, but there is no cure," Boyd said.</p><p>While we wait for treatment and a vaccine, Hirsch, who treats patients hospitalized for COVID-19 complications on a daily basis, says everyone can do their part by washing hands, wearing a mask, and staying 6 feet apart.</p><p>"As an infectious disease doctor working in the hospital, I see the damage of the pandemic and the worst cases of what's happening. We are trying to get the best possible outcome and confronting this overwhelming biologic reality of this terrible epidemic the best we can," Hirsch said.</p><p>Everyone at home can help in the fight too, he adds.</p><p>"Follow information that is science- and evidence-based, and avoid that which is not," he said.</p>
- WHO Declares Global Health Emergency as Coronavirus Cases ... ›
- Here's What We Know About Ibuprofen and COVID-19 - EcoWatch ›
- Trump's Budget Plan: A Push for Even Greater Environmental ... ›
- Trump Pushed for Mining Project That Could Destroy Alaska Salmon ... ›