The fossil-fuel revolution: Oil, engines and electricity

3.1 Oil began as lamp fuel and became the leading fuel of the 20th century

The modern oil industry dates from 1859, when Edwin Drake's well at Titusville in Pennsylvania struck oil, and from the same years in Baku on the Caspian. The first big market was not transport but light. Crude oil was distilled into kerosene, which burned in lamps more brightly and cheaply than whale oil or candles. The lighter fractions, including what we now call gasoline, were often treated as an awkward by-product.

Oil had physical advantages that would decide its future. As a liquid it can be pumped through pipes, poured into tanks, stored in bulk and loaded onto ships with little labour. It carries more energy per kilogram than coal, around 42 MJ against 20 to 30 MJ, and much more per litre than any gas. It burns cleanly enough to be injected into engine cylinders. And it can be refined into a range of products tuned to particular uses.

Those properties made oil ideal for vehicles, and vehicles turned out to be the growth market of the century. Coal remained the main fuel of industry and power stations, but oil's share kept rising. By Smil's count in Energy and Civilization, oil's contribution to world primary energy overtook coal's around 1964. Coal had held the top position for less than a century globally, and oil took it within about 105 years of Drake's well.

That crossover was itself a slow transition. Oil took decades to move from a few per cent of world supply to a leading share, following the same pattern coal had shown a century earlier.

• Smil, Oil: A Beginner's Guide (2008) · via Smil Mastery Course, M5 'Oil and the internal combustion engine'
• Smil, Energy and Civilization: A History (2017) · via Smil Mastery Course, M5 'Oil and the internal combustion engine'

3.2 Internal combustion engines got light enough to move cars and lift aircraft

A steam engine burns fuel outside the cylinder to make steam. An internal combustion engine burns it inside, directly pushing the piston. Nikolaus Otto's four-stroke engine of 1876 (intake, compression, power, exhaust) ran on town gas and set the pattern still used in most cars. In 1886 Karl Benz built a three-wheeled car with a gasoline engine, and Gottlieb Daimler and Wilhelm Maybach produced their own engines and vehicles. Smil notes that the 1901 Mercedes 35, designed by Maybach, already had the essential layout of a modern car.

Rudolf Diesel patented his engine in 1892 and had it working in 1897. It compresses air so strongly that the air becomes hot enough to ignite fuel sprayed into it, with no spark. The high compression gives higher efficiency than a gasoline engine. Diesels now power almost all ships, trucks, many trains, tractors and gensets, and Smil calls them a prime mover of globalisation.

The decisive change was in weight. Steam engines of the 1880s, with their boilers, weighed on the order of 150 grams per watt of power. Internal combustion engines were far lighter, and aircraft engines fell towards about 1 gram per watt by the 1940s. That mattered most for flight, where the engine must lift itself. The Wright brothers built their own aluminium-block engine of roughly 9 kW in 1903 because no available engine was light enough.

Cars became a mass product in the United States first. Ford's Model T, built from 1908 to 1927, sold about 15 million units and turned the car from a rich man's toy into a working family's tool.

• Smil, Two Prime Movers of Globalization: The History and Impact of Diesel Engines and Gas Turbines (2010) · via Smil Mastery Course, M5 'Oil and the internal combustion engine'
• Smil, Creating the Twentieth Century: Technical Innovations of 1867-1914 (2005) · via Smil Mastery Course, M5 'Oil and the internal combustion engine'

3.3 Electricity is a new quality of energy, not a new fuel

Electricity does not come out of the ground. It has to be generated from something else: burning coal, falling water, later uranium, wind and sunlight. What makes it valuable is what happens next. It can be carried along wires almost instantly to any building, switched on and off at will, measured precisely, and converted into light, motion, heat or information with high efficiency and no smoke at the point of use. Smil calls it a new quality of energy.

Thomas Edison's achievement was a whole system rather than a single invention. His Pearl Street Station in New York, opened in 1882, combined steam-driven dynamos, underground cables, meters, fuses, switches and long-lasting carbon-filament lamps. It was the first commercial central power plant.

Edison used direct current, which is hard to transmit over long distances. Nikola Tesla's induction motor and George Westinghouse's alternating current networks, using transformers to raise voltage for transmission and lower it for use, solved that problem. The large hydro station at Niagara Falls, opened in 1895, sealed the victory of AC, which still runs almost every grid.

The prime mover changed too. Charles Parsons patented the steam turbine in 1884: instead of pushing pistons back and forth, steam spins a rotor of blades at high speed, ideal for driving generators. Turbogenerators grew from about 7.5 kW in the first units to more than 1 GW today, the largest single machines in common use. Most of the world's coal, gas and nuclear electricity still comes from descendants of Parsons's design.

• Smil, Creating the Twentieth Century: Technical Innovations of 1867-1914 (2005) · via Smil Mastery Course, M5 'Electricity: the new quality of energy'
• Smil, Energy and Civilization: A History (2017) · via Smil Mastery Course, M5 'Electricity: the new quality of energy'

3.4 Electric motors rebuilt factories and made light almost free

Early factories were organised around a single prime mover. A water wheel or steam engine turned a long line shaft running the length of the building, and every machine took its power through leather belts from that shaft. Machines had to be placed where the shaft ran, not where the work flow suggested. Belts slipped, broke and wasted energy, and the whole shaft turned even when only one machine was in use.

Electric motors cut that link. Each machine could have its own motor, sized for its job and switched on only when needed. Engineers could lay out a plant in the order the product was made, let in light from above because the overhead shafting had gone, and add or move machines easily. Smil sees this reorganisation, which spread through American industry in the 1920s, as a large and underrated source of productivity growth.

Lighting shows the gains even more starkly. A candle turns only a tiny fraction of its energy into visible light. Kerosene lamps were better, carbon-filament bulbs better still, tungsten filaments and fluorescent tubes better again, and today's LEDs best of all. Over the whole run, the light obtained from a unit of energy has risen several hundredfold. At the same time electricity itself became cheap: in Numbers Don't Lie Smil notes that US residential electricity cost about 97% less in real terms in 2019 than in 1902.

Electricity's share of final energy has been rising ever since. It now powers motors, lighting, electronics and data, and is increasingly used for heating and transport, which is why it sits at the centre of plans to decarbonise.

• Smil, Numbers Don't Lie: 71 Stories to Help Us Understand the Modern World (2020) · via Smil Mastery Course, M5 'Electricity: the new quality of energy'
• Smil, Creating the Twentieth Century: Technical Innovations of 1867-1914 (2005) · via Smil Mastery Course, M5 'Electricity: the new quality of energy'

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Check your understanding

What was crude oil's first major market in the 1860s?

How does a diesel engine ignite its fuel?

Why did electric motors raise factory productivity?