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Hanley Sustainability Institute

Brecha: Coal a key 'knob' to turn off to slow carbon dioxide emissions

By Robert Brecha, PhD

NOTE: University of Dayton physics professor Robert Brecha is a co-author of Climate Analytics’ report on coal exit that was published ahead of the United Nations Climate Action Summit. Brecha is on leave under a European Union Marie Curie Fellowship working with Climate Analytics in Germany on sustainable energy access and system transformation in Least Developed Countries (LDCs) and Small Island Developing States (SIDS).

There is still a disconnect among what climate science tells us will be the likely consequences and impacts of continued rapid climate change, the willingness of policymakers to truly take projections seriously and the internalization of citizens in wealthy countries to realize that within a generation our energy system and many other consumption patterns will change.

Thirty years of periodic summaries by the Intergovernmental Panel on Climate Change (IPCC) of the state of climate science have not done enough to bring the seriousness of the climate crisis to a broad level of consciousness. Fundamentally, it is important to realize there are really only a small number of “knobs” that need to be turned – changes that must be made – that are dramatic, but also can have many positive aspects even beyond the mitigation of the worst impacts of climate change itself.

Over the past decades scientists have come to recognize there is a straightforward relationship between any given temperature goal and the amount of carbon dioxide that can be emitted over time. The longer we emit CO2, the higher the temperature will go; the less the science says that global average temperature can change without causing irreversible and serious consequences, the sooner we have to stop emitting CO2.

To meet the “carbon budget,” there is really no choice except to stop using fossil fuels; a 2018 Special Report on the Global Warming of 1.5°C (SR1.5) gives some guidelines to the necessary steps. Another recently released report by the think tank Climate Analytics (“Global and regional coal phase-out requirements of the Paris Agreement:  Insights from the IPCC Special Report on 1.5°C”) looks more specifically at how coal use fares over the next few decades. The conclusions mainly echo those that have become increasingly clear over the last few years – coal-fired electricity has a grim future, and to maintain consistency with the Paris Agreement (PA) target of holding global temperature change below 1.5°C – will have to disappear from the global power mix by the 2040s. This is even earlier than what has previously been acknowledged, partly because those studying the potential impacts of climate change are realizing every half-degree of warming matters, and partly because the world has been “spending” its carbon emissions budget ever more quickly over the past decade, leaving less and less room for future emissions. Coal is the highest emission fuel, and therefore eliminating it from the mix is one of the quickest ways to significantly decrease emissions.

One of the ideas summarized in the Climate Analytics report is that of regional variations in how coal should be phased out over time. Wealthier countries that have the highest historical emissions from coal will need to phase out coal sooner – by the early 2030s. However, even newly industrializing and modernizing countries such as China, others in Southeast Asia, and in the reformed economies of Eastern Europe will be required to make the transition away from coal soon thereafter.  A key point of the report is that even existing coal-fired power plants, if they were to run to their full expected lifetimes, would be responsible for far more emissions than their share of the total carbon budget would allow. Therefore it follows that no new coal power plants should be built, as United Nations Secretary-General António Guterres has already forcefully urged.

In the U.S., starting under the Obama administration and continuing thus far under the Trump administration, a large fraction of coal-power capacity has been taken off line. Whereas coal power made up 50 percent of U.S. electricity until the mid-2000s, it is now down to about half that amount. The reason for the shift has been simple – the economics of coal power have lost to natural gas and, increasingly, to renewables such as wind and solar power. There was not a strategic plan to decrease U.S. carbon emissions; if that were true, and if it were to be in line with the PA, production of oil and natural gas would not have been encouraged so strongly.

But the fact is natural gas electricity produces less than half the emissions per kilowatt-hour than does coal power – if we do not take into account the significant leakage of methane during fracking. With the advent of large amounts of fracked natural gas around the country, the price for natural gas on the markets is relatively low. Because there was a large existing capacity of natural gas power plants, and more were built relatively quickly, natural gas was able to supplant coal, thereby reducing CO2 emissions.

This is, however, only a temporary advantage, since even natural gas emissions are far too high to allow PA goals to be reached. Interestingly enough, the cost for renewables is sinking so rapidly that the threat to coal power will only increase further. A recent study showed that Arizonans could save billions of dollars during the next few decades by shutting down their coal plants by 2023 and replacing them with utility-scale solar photovoltaics and batteries. This is a truly remarkable development – not just to build new solar instead of new coal, but to actually replace existing plants and save money for customers – that is a hard argument to counter.  The general trend of lower renewable electricity costs compared to fossil fuels is one of the arguments made in the Climate Analytics report.

A few other important points are addressed in the Climate Analytics report. As international financial organizations, from the World Bank to private and national banks, begin to look more carefully at the seriousness of climate change, and the increasing willingness of some countries to undertake energy system transformations, they are realizing any investments in coal will be risky. If there is anything financial institutions do not like, it is risk, and the reaction of some has been to dial back significantly their support for coal power plant projects worldwide. The pipeline for new coal projects has shrunk by about 75 percent in the past five years as plans are canceled and replaced by other electricity sources. Increasingly, governments and finance institutions also are divesting from coal portfolios generally, adding to the pressure.

There are other reasons for moving away from coal aside from climate mitigation benefits and even beyond the increasingly clear cost savings for consumers. Coal power plants are often old and result in emissions of sulfur dioxide, mercury and particulate matter.. Although these emissions can be reduced, they result in “external costs” to society. That is, health costs from coal-power pollution are paid for by society as a whole (and often by a disadvantaged population who live near the plants) but these costs are not included in the price we pay for electricity. If these external costs were priced into our electricity bills, coal power would become even less economically competitive than it is now. Essentially all economists agree that if external costs such as health (or climate change damages to the future) are not included in market prices, those markets cannot be considered to be functioning properly.

The power sector is a key to the overall energy system transformation because other sectors can use electricity to “decarbonize” (buildings, transportation), and because the pathway for transitioning away from fossil fuels is clear. There are side benefits of moving away from coal as well as challenges to be considered such as how to achieve a just transition for those now working in the coal sector.

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