metamorphic rock which is nearly pure carbon). There were various periods of extensive coal formation in our planet’s past, the first major one being known, for perhaps obvious reasons, as the “Carboniferous Period” from 360-290 million years ago. 108 There have been others as well, as the Earth has occasionally fallen into similar environmental conditions in what are sometimes termed “coal ages.” Being buried effectively “sequestered” this biogenic carbon from the reactive free oxygen in Earth’s atmosphere. We are currently engaged in de - sequestering it at a rapid pace. The energy released from the burning of coal with oxygen is the principal source of electricity. Like all other non- renewable resources, we have used the “best first,” leaving us to work our way down through increasingly remote energy to burn successively lower- grade coals which are less energy-dense. Most of the coal being burned today is “bituminous,” and that is now near peak and declining, leaving inferior coals which are only about twice as energy dense as wood. Coal, globally, peaked in use in 2013, at least for now. 109
Coal is far less useful than oil because it is a solid with lower energy density. As a liquid fuel with hydrogen bonds, oil’s ease of transport and use in lightweight high-powered vehicles and other applications make oil beat coal hands down. Coal may be converted into a liquid fuel by a series of chemical reactions known as the “Fischer - Tropsch” process, which notably was used by Hitler’s Germany to produce an “oil substitute” during WWII, but this is a very energy-intensive process. Scaling Fischer-Tropsch oil creation using coal to match the flow of oil volume we currently use would be a massive expensive undertaking with humongous CO 2 output and other pollution streams. 110
TaaL: Coal is cool stuff. We don’t have any on my world. The high -grade anthracite is beautiful, hard, shiny and black. Your parents and grandparents
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