Fossil Fuels: Abundant, Chemically Stable, Energy-dense

“Energy fundamentals explain why oil, gas, and coal brought an end to mankind’s renewable energy era. The same fundamentals explain why decreasing the market share of fossil fuels requires so much government intervention at the expense of consumers and taxpayers.”

The use of fossil fuels grew and remained widespread for several reasons. First, they are abundant. Vast amounts of living matter on the earth accumulated over eons of time. This accumulation, combined with the ever-active nature of the earth’s surface, meant that large volumes of ancient bio-matter were captured in the earth’s crust and transformed into fossil fuels.

Secondly, hydrocarbon compounds (those consisting mainly of carbon and hydrogen) are very chemically stable. Though these compounds might change form over long periods of time and under intense pressure and temperature beneath the earth’s surface, chemical stability preserves their inherent structure and subsequent energy content.

Thirdly, fossil fuels are very energy-compact. Carbon-carbon and carbon-hydrogen chemical bonds when broken (by burning) release amazing amounts of energy. Engineers and scientists measure energy content in terms of kilojoules or BTUs (British Thermal Units). Energy measured in these units is not something most of us can readily comprehend. But let’s try.

It takes around 9300 BTUs to heat and boil a gallon of water starting from room temperature. A million BTUs will boil 108 gallons of water. This amount of energy is equivalent to 293 kilowatt-hours (kWh). In 2013, the average Texas home used around 1200 kWh or 4 million BTUs per month. A 100 watt light bulb that remained lit for a month would use around 73 kWh. A kilojoule and a BTU are roughly an equivalent amount of energy.

According to the US Energy Information Agency (EIA), the amount of fossil fuels that contain a million BTUs of energy is summarized in the following table.

(1) As liquefied natural gas (LNG)

A volume of one cubic foot is equivalent to 7.5 gallons.

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Fossil fuels are easily converted to other useful forms of energy

A fourth point to be made about fossil fuels is the ease by which their energy content can be converted into useful work. By “ease” I mean a combination of the efficiency of energy conversion as well as the cost of constructing and operating power generation equipment. The combustion (burning) of fossil fuels is based on well-known and long-established technologies. Today’s energy conversion technologies (power plants and internal combustion engines) are cost-effective, efficient, and safe.

According to the EIA, electricity generated by coal, oil, and natural gas power plants in the US currently convert, on average, around a third of the intrinsic fuel energy content into electrical energy (before transmission and usage losses). Newer technologies, such as combined-cycle gas turbine plants, can achieve conversion efficiencies as high as 60%.

And finally there is the cost advantage, as can be clearly demonstrated by the following table.

1. 1 ton = 2000 pounds
2. 1 barrel = 42 gallons
3.  1 MCF = 1000 cubic feet (134 gallons) measured at atmospheric conditions. An MCF of natural gas (methane) occupies 1.5 cubic feet when liquefied (LNG)

In 2015, Texans paid, on average, around 12 cents per kWh for residential electricity.

In May 2015, over 80% of total US energy consumption was from fossil fuels. Approximately 20% of fossil fuel use was coal, 32% natural gas, and 48% oil.

The above table demonstrates why oil is not generally used as a fixed-source fuel (i.e., cost). Fuels derived from oil (e.g., gasoline, diesel, jet fuel), however, are easily transported by truck, rail, or pipeline. They are obviously also carried and directly used by motorized vehicles with internal combustion engines. Liquid petroleum fuels accounted for 92% of the energy used for transportation in the US in 2014. Biofuels (ethanol and biodiesel) contributed around 5%, natural gas 3%, and electricity less than 1%.

Another important fossil fuel is Liquefied Natural Gas (LNG). LNG is methane gas cooled to negative 260 degrees Fahrenheit. Liquefication of methane achieves a high energy density for transportation purposes. There is currently a large global trade in LNG. It is also being increasingly deployed as a transportation fuel, particularly for rail and long-distance trucking. Significant public LNG refueling capacity (principally for trucking) was under development in the US in 2015.

Energy fundamentals explain why oil, gas, and coal brought an end to mankind’s renewable energy era. The same fundamentals explain why decreasing the market share of fossil fuels requires so much government intervention at the expense of consumers and taxpayers.

This post is taken from chapter 1 of my energy primer, Oil & Gas and the Texas Railroad Commission: Lessons for Regulating a Free Society.