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.
.@Ecowatch: Methane Emissions From Onshore Oil and Gas Equivalent to 14 Coal Plants Powered for One Year https://t.co/Lw4XSoCYG6 #fracking— Frack Action (@Frack Action)1466522501.0
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.
Many people shop online for everything from clothes to appliances. If they do not like the product, they simply return it. But there's an environmental cost to returns.
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EcoWatch Daily Newsletter
By Dolf Gielen and Morgan Bazilian
John Kerry helped bring the world into the Paris climate agreement and expanded America's reputation as a climate leader. That reputation is now in tatters, and President-elect Joe Biden is asking Kerry to rebuild it again – this time as U.S. climate envoy.
Energy Is at the Center of the Climate Challenge<p>The <a href="https://science2017.globalchange.gov/chapter/1/" target="_blank">effects of climate change</a> are already evident across the globe, from <a href="https://theconversation.com/100-degrees-in-siberia-5-ways-the-extreme-arctic-heat-wave-follows-a-disturbing-pattern-141442" target="_blank">extreme heat waves</a> to <a href="https://science2017.globalchange.gov/chapter/12/" target="_blank">sea level rise</a>. But while the challenge is daunting, there is hope. Solar and wind power have become the <a href="https://www.irena.org/publications/2020/Jun/Renewable-Power-Costs-in-2019" target="_blank">cheapest forms of power generation globally</a>, and technology progress and innovation continue apace to support a transition to clean energy.</p><p>In the U.S. under a Biden administration, long-term national climate legislation will depend on who controls the Senate, and that won't be clear until after two run-off elections in Georgia in January.</p><p>But there is no shortage of <a href="https://www.bloomberg.com/features/2020-biden-climate-change-advice/" target="_blank">ideas for ways Biden</a> could still take action even if his proposals are blocked in Congress. For example, he could use executive orders and direct government agencies to tighten regulations on greenhouse gas emissions; increase research and development in clean energy technologies; and empower states to exceed national standards, <a href="https://www.reuters.com/article/us-autos-emissions-california/defying-trump-california-locks-in-vehicle-emission-deals-with-major-automakers-idUSKCN25D2CH" target="_blank" rel="noopener noreferrer">as California did in the past with auto emission standards</a>. A focus on a just and equitable transition for communities and people affected by the decline of fossil fuels will also be key to creating a sustainable transition.</p><p>The U.S. position as the world's largest oil and gas producer and consumer creates political challenges for any administration. U.S. forays into European energy security are often treated with suspicion. Recently, France blocked <a href="https://www.wsj.com/articles/frances-engie-backs-out-of-u-s-lng-deal-11604435609" target="_blank">a multi-billion dollar contract</a> to buy U.S. liquefied natural gas because of concerns about limited emissions regulations in Texas.</p><p>Strengthening cooperation and partnerships with like-minded countries will be critical to bring about a transition to cleaner energy as well as sustainability in agriculture, forestry, water and other sectors of the global economy.</p>
Creating a Global Sustainable Transition<p>How the world recovers from COVID-19's economic damage could help drive a lasting shift in the global energy mix.</p><p>Nearly one-third of Europe's US$2 trillion economic relief package <a href="https://www.bloomberg.com/news/articles/2020-07-21/eu-approves-biggest-green-stimulus-in-history-with-572-billion-plan" target="_blank" rel="noopener noreferrer">involves investments that are also good for the climate</a>. The European Union is also strengthening its 2030 climate targets, though each country's energy and climate plans will be critical for successfully implementing them. The <a href="https://joebiden.com/clean-energy/" target="_blank" rel="noopener noreferrer">Biden plan</a> – including a $2 trillion commitment to developing sustainable energy and infrastructure – is aligned with a global energy transition, but its implementation is also uncertain.</p><p>Once Biden takes office, Kerry will be joining ongoing <a href="https://www.un.org/en/conferences/energy2021/about#:%7E:text=The%20overarching%20goal%20of%20the,2030%20Agenda%20for%20Sustainable%20Development.&text=Accelerate%20delivery%20of%20United%20Nations,related%20issues%20at%20all%20levels." target="_blank" rel="noopener noreferrer">high-level discussions on the energy transition</a> at the U.N. General Assembly and other gatherings of international leaders. With the U.S. no longer obstructing work on climate issues, the G-7 and G-20 have more potential for progress on energy and climate.</p><p>Lots of technical details still need to be worked out, including international trade frameworks and standards that can help countries lower greenhouse gas emissions enough to keep global warming in check. <a href="https://www.carbonpricingleadership.org/what" target="_blank" rel="noopener noreferrer">Carbon pricing</a> and <a href="https://www.csis.org/analysis/how-can-europe-get-carbon-border-adjustment-right" target="_blank" rel="noopener noreferrer">carbon border adjustment taxes</a>, which create incentive for companies to reduce emissions, may be part of it. A consistent and comprehensive set of national energy transition plans will also be needed.</p><p>The global shift to <a href="https://www.irena.org/publications/2019/Jan/A-New-World-The-Geopolitics-of-the-Energy-Transformation" target="_blank">clean energy will also have geopolitical implications for countries and regions</a>, and this will have a profound impact on wider international relations. Kerry, with his experience as secretary of state in the Obama administration, and Biden's plan to make the climate envoy position part of the National Security Council, may help mend these relations. In doing so, the U.S. may again join the wider community of countries willing to lead.</p>
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By Maria Caffrey
As we approach the holidays I, like most people, have been reflecting on everything 2020 has given us (or taken away) while starting to look ahead to 2021.
We Need More Than Listening<p>By now we have all become sadly accustomed to the current administration sidelining scientists, most prominently Dr. Anthony Fauci, because the facts they provide do not fit with the political rhetoric of the moment.</p><p>I have <a href="https://www.csldf.org/2019/08/22/csldf-helps-climate-scientist-maria-caffrey-fight-for-scientific-integrity/" target="_blank">my own history</a> of filing a scientific integrity complaint with the National Park Service (which falls under the Department of the Interior) after senior ranking employees attempted to censor one of my scientific reports. I know all too well the damage and pain that these actions cause, not just for the individual scientist, but also because these <a href="https://www.ucsusa.org/resources/attacks-on-science" target="_blank" rel="noopener noreferrer">attacks on science</a> over the last few years have undermined sound, evidence-based decision making.</p><p>President-elect Biden has repeatedly said that he will <a href="https://thehill.com/homenews/521638-trump-biden-will-listen-to-the-scientists-if-elected" target="_blank" rel="noopener noreferrer">listen to the scientists</a>. While this is certainly a welcome change, listening can only take us so far. This past week Lauren Kurtz from the <a href="https://www.csldf.org/" target="_blank" rel="noopener noreferrer">Climate Science Legal Defense Fund</a> and my colleague <a href="https://www.ucsusa.org/about/people/gretchen-goldman" target="_blank" rel="noopener noreferrer">Gretchen Goldman</a> published <a href="https://www.scientificamerican.com/article/ten-steps-that-can-restore-scientific-integrity-in-government/" target="_blank" rel="noopener noreferrer">an article</a> listing 10 actions the new administration should implement to show their commitment to strengthening government science:</p><ol><li>Clearly prohibit political interference and censorship.</li><li>Protect scientists' communication rights.</li><li>Acknowledge that attempts to violate scientific integrity, even if ultimately not fruitful, are still violations.</li><li>Protect federal scientists' right to provide information to Congress and other lawmakers.</li><li>Commit to incorporating the best science as part of agency decisions.</li><li>Elevate agency scientific integrity policies to have the full force of law.</li><li>Publicly release anonymized information about scientific integrity complaints and their resolutions at every agency.</li><li>Institute an intra-agency workforce, potentially under the White House <a href="https://www.ucsusa.org/sites/default/files/2020-09/strengthening-science-and-si-at-ostp.pdf" target="_blank" rel="noopener noreferrer">Office of Science and Technology Policy</a>, to coordinate scientific integrity efforts across agencies, foster discussion of policy improvements, and standardize criteria for policies across agencies.</li><li>Strengthen whistleblower protections.</li><li>Ensure that policies cover all actors who will be dealing with science.</li></ol>
Time for Action<p>I have spoken to many scientists, particularly federal scientists, who are eager to turn the page so they can hurry back to the work they had been doing before this administration, but I urge caution in assuming that things can be "normal" again.</p><p>Before Trump, I naively thought the scientific integrity policies established during the <a href="https://obamawhitehouse.archives.gov/blog/2016/12/19/scientific-integrity-policies-update" target="_blank">Obama administration</a> would be sufficient. I never imagined that any administration could so willfully ignore and attack expert advice and evidence that is intended to protect us and our public lands.</p><p>I have personally witnessed how hard our federal scientists work. They put in long hours with minimal pay (far less that what they could get if they worked in private industry) to pursue one simple goal: to make things better for the nation.</p><p>We need stronger scientific integrity policies to protect these people and their work. But more than that, we need stronger scientific integrity laws because they also benefit society.</p>
By Andrea Germanos
Environmental campaigners stressed the need for the incoming Biden White House to put in place permanent protections for Alaska's Bristol Bay after the Trump administration on Wednesday denied a permit for the proposed Pebble Mine that threatened "lasting harm to this phenomenally productive ecosystem" and death to the area's Indigenous culture.
<div id="da98c" class="rm-shortcode" data-rm-shortcode-id="478a197b7c59c92787c92bec92f1ac39"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1331662923710693376" data-partner="rebelmouse"><div style="margin:1em 0">Bristol Bay forever, Pebble mine never. #NoPebbleMine #SaveBristolBay https://t.co/CBQ9zuy8A5</div> — Save Bristol Bay (@Save Bristol Bay)<a href="https://twitter.com/SaveBristolBay/statuses/1331662923710693376">1606328156.0</a></blockquote></div>
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By Gwen Ranniger
In the midst of a pandemic, sales of cleaning products have skyrocketed, and many feel a need to clean more often. Knowing what to look for when purchasing cleaning supplies can help prevent unwanted and dangerous toxics from entering your home.