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Coal: The Dirtiest Fuel

By Benjamin Kahane

Depending on how much pressure and temperature to which it has been subject, coal is a sedimentary or metamorphic rock comprised mostly of carbon. Coal is a fossil fuel used primarily in the generation of electricity. To turn coal into electricity, the rock is pulverized then combusted in a furnace, the heat from which converts water into steam used to spin turbine blades to create electricity.

Coal is mined from the Earth in one of two basic methods: surface mining and underground mining. Surface mining — or strip mining — is the most economical way to extract coal if it is located close to the surface; it’s also the most ecologically devastating method, since the surface of the land, complete with trees, topsoil and all plants, are removed. This method is particularly common in the Appalachian Mountains, where the entire tops of mountains are removed, with debris pushed into valley streams.

Figure 1: Historical U.S. electric grid production, in quadrillion British thermal units, by fuel type. When it comes to powering the electric grid, coal is king.

Underground mining accounts for about 60 percent of world coal production and is the preferred method when the coal seams are too deep or the land is protected. Strip mining accounts for the remaining 40 percent. However, in the United States the numbers are reversed, and surface mining dominates.

There are many negative environmental impacts to using coal. Although coal is comprised mostly of carbon, smaller quantities of sulfur, hydrogen, oxygen, nitrogen, and other heavy metals including mercury also exist in the coal we burn. There are higher and lower qualities of coal, just like petroleum, however the use of lower quality coal is widespread due to more widespread availability. If these harmful byproducts are not removed before or during combustion, they can lead to damaging events such as acid rain, background radiation exposure and cancer in humans and animals. Carbon dioxide emissions are also a cause for concern since carbon dioxide is a major contributor to climate change.

Figure 2: Historical U.S. coal mining, in million short tons, by type of extraction.

There have been some major technological advances in the pursuit of so-called “clean coal.” Power plants have been outfitted with scrubbers and filters to reduce the pollution emitted. Carbon dioxide sequestering, or containment, also has been explored as a method to mitigate greenhouse gas emissions.

Many people believe we need to rid ourselves of this dirty form of energy as soon as possible. Unfortunately, that is a lofty goal: We’ll need to put into place thousands of gigawatts of alternative energy sources before being able to wean ourselves off of coal fired electricity.

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Benjamin Kahane is a utility scale project engineer at SunEdison, where he designs photovoltaic solar energy systems. He has provided engineering support for the development of more than 100 megawatts of ground-mounted photovoltaic projects across North America. Kahane previously worked as a project engineer developing photovoltaic installations at Conergy. He earned his master’s degree in sustainable energy engineering at the University of Maryland, College Park.

The Jewish Energy Guide presents a comprehensive Jewish approach to the challenges of energy security and climate change and offers a blueprint for the Jewish community to achieve a 14% reduction in greenhouse gas emissions by September of 2014, which is the next Shmittah, or sabbatical, year in the Jewish calendar.

The Jewish Energy Guide is part of COEJL’s Jewish Energy Network, a collaborative effort with Jewcology’s Year of Action to engage Jews in energy action and advocacy. The Guide was created in partnership with the Green Zionist Alliance.

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