Burning coal creates a huge flow of flue gas, mostly carbon dioxide CO2 and water from the combustion process, along with sulfur dioxide (from sulfur contaminants in the coal), nitrogen oxides, mercury and other contaminants. Emissions levels and pollution control requirements, mandated by the US EPA and other agencies, are the subject of continuing political discussion and controversy.

In a small number of cases, US electric utilities are experimenting with coal gasification, a potentially cleaner, more efficient way to make electricity from coal. In this so-called “clean coal” process, coal is cooked with oxygen at high temperatures to yield a mixture of hydrogen and carbon monoxide CO gases, plus carbon dioxide, water and a glassy solid residue.

The hydrogen plus CO “synthesis gas” fires a jet engine like turbine generator, and heat recovered from the turbine exhaust and from the gasification reaction is used to create steam to generate additional electricity. According to coal gasification proponents, the nature of the processes makes it much easier to isolate and dispose of contaminants like sulfur, mercury and other metals, and CO2 greenhouse gas emissions.

In addition to generating electricity, relatively small amounts of specialty grades of coal are converted by baking into coke, nearly pure carbon used to make high quality steel.

Like coal, the petroleum based hydrocarbon mixture we know as crude oil, found in isolated surface seeps, has a long history of human utilization. Industrialization of petroleum, from purposely drilled dwells, began in in the late 1800s (again, in Pennsylvania). From the beginning, their very high energy content (as ‘energy per pound’ or ‘energy per gallon’) and their easy transportability created a strong demand for the liquid hydrocarbon products derived from crude oil.

Kerosene (replacing whale oil) for lighting was among oil’s earliest ‘killer applications’, but soon, the invention of the automobile created a need for gasoline and lubricants that has driven the oil business ever since. The transportation sector today - cars, truck, trains, etc - accounts for about one third of US energy usage, essentially all of that derived from crude oil. Gasoline and diesel fuel, lubricants and functional fluids make up the majority of consumption, along with rubber and plastic components built from petroleum based raw materials.