written 21 January 2024
published 28 January 2024
Coal is created from dead plant matter by the heat and pressure of deep geologic burial, applied over millions of years. Depending on pressure and temperature, coal qualities and uses vary from lignite (lowest, electrical generation), through bituminous (steam propulsion), to anthracite (highest, heating). Coal of any quality is mostly carbon, with hydrogen/carbon ratios of less than 1, and often includes sulfur, mercury, uranium, thorium, and arsenic.
Coal has been used for thousands of years, the first developed fossil fuel. Coal was originally gathered at the sea shore, where coastal erosion exposed seams. As with all finite resources, the easiest coal resources were quickly depleted. Pit mining arose to meet the increasing demand, as coal became used for residential cooking and heating. The rise of the Industrial Revolution was powered by coal, demanding increased production with deep shaft mining. Extraction has now expanded to the more invasive, environmentally damaging, mountain top removal. Rather than digging a hole down to where the coal seams lie, the whole mountain top is removed, pushed into the surrounding valleys, allowing recovery of the coal using massive machines.
Coal is the most abundant of fossil fuels, but also the most limited, only good for external combustion industries like electric power production and steel. These days, coal produces 34 percent of global electricity, and 28 percent of all energy. But the low ratio of hydrogen to carbon means coal combustion generates twice as much CO2 as natural gas combustion, per unit of energy.
The trace elements in coal also degrade the environment. Sulfur dioxide emissions create hazardous air pollution particulates and sulfuric acid rain, which leaches aluminum into the environment. Mercury is toxic, and the radioactive elements are carcinogenic. Consequently, coal smokestack emissions cause asthma, strokes, reduced intelligence, arterial blockages, heart attacks, congestive heart failure, cardiac arrhythmias, and lung cancer. Workers breathing coal dust suffer from "black lung", killing about 1500 a year in the US. When local residents complained about adverse health impact, very high smoke stacks were built so the contamination was more wide-spread further down wind. The industry mantra is "the pollution solution is dilution".
Global coal consumption is about 9 billion tons a year, which generates 900 million tons of toxic ash, a massive waste disposal problem, expensive to handle correctly, so it often isn't. China consumes half of all the coal used, and India and the US use another 10 percent each. Air quality in China is appalling. The US health care costs associated with coal are $70B annually.
Coal seam fires are a global problem. These can start from spontaneous combustion underground, or be ignited by surface fires at exposed deposits. Once ignited, a coal seam fire is difficult to extinguish. The ground can subside and release toxic combustion gases, both problematic. The fire can break out to the surface, causing other wild fires. In Centralia, Pennsylvania, a fire ignited in 1962 still burns. Coal fires in Australia and Tajikistan have been burning for thousands of years.
As awareness of the climate crisis has grown, focus on the problems of coal have increased. "Clean coal" is mostly a political fiction. While there are technologies that can capture the CO2 from the stack, they are so expensive and energy intensive that the process is uneconomical in the face of declining renewable costs. The rapidly expanding climate crisis is forcing a decline in coal consumption, which peaked in 2008 at 30 percent of overall energy production. US coal consumption is down 10 percent from 2008, and coal plants are being repurposed.
But the industry refuses to accept that their assets are now "stranded", and their investment headed toward bankruptcy, if we want a habitable planet. In the face of reduced domestic demand, they try to increase exports to Asia, which still burns a lot of coal. However, less than 10 percent of domestic coal is shipped from western North American ports and those communities vigorously oppose allowing new or expanded export of coal through them, not only for global environmental concerns, but because the shipping process itself is dirty and toxic to the local area. A few years ago, plans were filed to ship unit trains of coal from Wyoming, through Mendocino county, for export from Eureka, but that plan failed.
A technological society needs energy, but we can no longer mindlessly kill people and the planet to achieve that goal. It's time to change our thinking.
