Smil examines historical energy transitions quantitatively, from wood to coal, coal to oil, and the additions of natural gas, nuclear and renewables, and derives from the record how long such transitions take and what determines their pace.
The empirical finding is the argument. Every major energy transition has taken between fifty and seventy years from the point a new source reached a small share of primary supply to the point it became dominant, and none has been fast. Coal took roughly sixty years to go from five percent to fifty percent of global primary energy. Oil took a similar period. Natural gas has still not completed the journey. The reason is scale: the existing energy system represents an enormous installed capital stock with long asset lives, the new source must be built out physically, and the supporting infrastructure of transport, storage and end-use equipment must be replaced alongside it.
He adds that transitions have historically been additions rather than substitutions. World coal consumption is higher now than when oil displaced it as the leading fuel, because total energy demand grew faster than the share shifted.
Smil is careful that this is a historical base rate rather than a physical law, and that policy and technology could in principle move faster. His position is that assertions of rapid transition should be measured against what has previously been achieved. Critics argue that solar and battery cost declines and the electrification of end uses represent a different dynamic from previous transitions.
Energy investors and policy readers who need historical base rates for how fast energy systems actually change.
Distinguished professor emeritus at the University of Manitoba; writes quantitative histories of energy, food, materials and technical change.
Each book counts the physical inputs an economy consumes - joules, tonnes of steel, ammonia, cement - and establishes the historical rates at which past energy transitions actually moved. Those numbers let an investor size decarbonisation timelines and test claims about how fast an energy system can be rebuilt.
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