Energy The Mover of Output Jes´usFern´andez-Villaverde1 September 26, 2021 1University of Pennsylvania Energy • For most of history, the main barrier for humans' output has been energy production. • Even today. Fortune's Global 500 by revenue, 6 out of the top 10 companies are in the energy sector: 2. State Grid. 3. China National Petroleum. 4. Sinopec Group. 5. Royal Dutch Shell. 6. Exxon Mobile. 10. BP. • Similar at a national level (for instance, 4 out of top 10 Spanish firms). 1 Energy: conflicts and challenges • Furthermore, access to energy has been a key driver of conflicts. • Indirectly, as struggles to control land and food sources. • More recently, direct links: 1. Japan's decision to go to war in 1941. 2. 1953 coup d'´etatagainst Mohammad Mosaddegh in Iran. 3. Gulf wars. • Challenge of decarbonizing the economy and increasing energy consumption of much of the world population. 2 Energy units a. 1 newton (N): unit of force = mass ∗ acceleration (kg ∗ m ∗ s−2). Force required to accelerate 1 kg ∗ m ∗ s−2. Given g = 9:80665m=s2, 1 newton is the weight on an apple. b. 1 joule (J): unit of energy = force ∗ distance (kg ∗ m2 ∗ s−2). Work transferred to an object when a force of one newton acts on that object in 1 m (energy= force ∗ distance). 1 joule is 1 apple lift 1 meter. c. 1 watt (W): unit of power = work/time (kg ∗ m2 ∗ s−3). 1 joule per second. Thus, 1 watt is 1 apple lift 1 meter in 1 second. 3 Energy consumed (history) 150 120 90 60 Gigajoules 30 0 1500 1550 1600 1650 1700 1750 1800 1850 1900 1950 2000 4 Energy consumed (US) • Extraordinary amounts of energy consumed every second. • Average U.S. person uses 11 kW (11 ∗ 103 W). • This is equivalent to: 1. Running three clothes dryers or 2. Using 100 laptops or 3. Using 100 humans' full muscle effort or 4. Consuming 1 barrel of oil every 5 days. • U.S. uses 3.6 TW (3:6 ∗ 1012 W). • And we use 50% less energy per 1$ produced than in 1980. 5 Energy consumed (world) • World uses 18 TW. • This is the equivalent of 18 ∗ 1012 apples lift 1 meter in 1 second. • Or the equivalent of lifting the USS Gerald R. Ford (≈ 108 kg) 18,367 meters into the air in 1 second (ignoring air friction). • Or the equivalent of lifting an Imperial I-Class Star Destroyer (≈ 4:44 ∗ 109kg) 413 meters into the air in 1 second (ignoring air friction as well). 6 7 8 Three energy transitions • From biomass, wind, and water to coal. • From coal to oil and gas. • From oil and gas to? 9 80% 70% 60% 50% 40% 30% 20% 10% Shares of primary energy consumption of primary energy Shares 0% 1875 1900 1925 1950 1975 2000 Petroleum Coal Natural Gas Biomass 10 10,000 1,000 100 10 1 0.1 Installed Capacity (GW, Log Scale) Log Installed Capacity (GW, 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 Years Since Inception Non−Hydro Renewables (2004−2018) Coal Power (1908−2000) Nuclear Capacity (1956−2000) Hydropower (1895−2018) Natural Gas (1903−2000) Wind Power (1984−2018) 11 1,000 100 10 1 Per thousand people Per 0.1 0.01 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 Motor Vehicles (1900−1950) Non−Farm Horses and Mules (1900−1950) Electric Cars (2011−2018) Motor Vehicles (2011−2016) 12 10,000 1,000 100 10 1 0.1 0.01 0.001 Units per thousand persons (log scale) Units per thousand persons (log 0.0001 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 125 130 135 140 145 Years since inception Passenger Cars (1900−2005) Bicycles (1870−2007) E−bikes (1997−2010) Laundry Dryers (1920−2006) Refrigerators (1918−2009) Washing Machines (1920−2008) Cellphones (1978−2010) Motorbikes (1900−2008) Electric Cars (2005−2018) 13 15000 14000 13000 12000 11000 Million tonnes oil equivalent 10000 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 Coal Hydroelectric Natural Gas Renewables Nuclear Energy Oil 14 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Africa Asia Pacific CIS Europe Middle East N. America S. & C. America Coal Hydroelectric Natural Gas Renewables Nuclear Energy Oil 15 Biomass • The sun provides earth all the energy that humans use in a year in ≈ 75 min. • Photosynthesis in plants, algae, and cyanobacteria transforms light energy into chemical energy. • The chemical energy becomes biomass (wood, animals, etc.). • Fossil fuels are transformed solar energy as well. • In fact, only nuclear and geothermal are sources of energy not (directly) linked with the sun. 16 Using the biomass (I) • Humans traditionally got their energy either from food or from fuel (wood, vegetable, animal, or rock oil, coal...). • Before internal combustion engine, fuel is used mainly for fire. • The ability of homo species to create and control fire appears for sure ≈ 250,000 BCE, probably ≈ 800,000 BCE in evidence from South Africa and Israel. • Ability to create and control fire is unique to home species, cultural and, as far as we can tell, universal to all anatomically modern humans. 17 18 Using the biomass (II) • The ability of homo species to create and control fire was also probably was crucial for evolution. • For example, cooking led to smaller jaws and gastrointestinal tracts. Perhaps (but disputed) to bigger brains. • More importantly, it led to better survival chances, better defenses, and to the ability to populate harsher environments. • Think about our ability to cook grains such as wheat and rice. • Catching Fire: How Cooking Made Us Human by Richard Wrangham. 19 Using the biomass (III) • Deep changes in the landscape over millennia. • For example, eucalyptus trees forest in Australia. • It also probably led to the first forms of gender-related division of labor. 20 Using the biomass more intensely • Neolithic revolution (≈ 10,000 BCE): domestication of plants and animals. • Culmination of a relatively fast process of behavioral innovations. • Use land to produce much more biomass than before: 1. Hunter-gatherers require ≈ 26 km2 of land per person. 2. Farmers require ≈ 0:26 km2 of land per person. • Dramatic change in population size. ≈ 10,000 BCE only between 2-4 million humans. • Additional uses. Example: the spread of cavalry. • Changes in environment: germs, dogs, etc. 21 530 . . 22 Figure 13. Modern behaviors and their time depths in Africa. Sally McBrearty & Alison S. Brooks. with the European Middle Paleolithic. that the terms ESA, MSA, and LSA are too While MSA and Middle Paleolithic tech- vague, broad, and temporally imprecise to nologies share common features (Thackeray be particularly illuminating when attempt- & Kelley, 1988; Thackeray, 1989, 1992, ing detailed behavioral reconstructions 2000), the evidence reviewed in this paper (Kleindienst, 1967). serves to highlight their essential differences. The presence of stone working techniques It is particularly critical that the Middle to such as backing in the African MSA at 80 ka Upper Paleolithic transition in Europe not shows a level of technical competence not be confused with the origin of H. sapiens. achieved until tens of thousands of years The European Middle to Upper Paleolithic later ouside the continent. Microwear transition represents the local replacement studies are in their infancy in Africa, but of the Neanderthals by H. sapiens, while in from artefact design and ethnographic evi- Africa, H. sapiens is a product of in situ dence it seems clear that MSA artefacts were evolution. The African MSA–LSA tran- habitually hafted, and some of them were sition is a cultural and technological change used as projectiles, perhaps in some cases that occurred many tens of thousands of propelled by the bow. From the long-term years later. Furthermore, the Middle to stylistic conservatism of barbed bone tools in Upper Paleolithic transition in Europe is a Central Africa, and the slowness with which change from mode 3 to mode 4 technology, this particular technology (but not bone while in Africa, modes 3, 4, and 5 are all tools in general) spread beyond the great already present in the African MSA. In fact, lakes region, Yellen (1998) concludes that the diversity in stone tool industries suggests MSA exchange networks may have Turchin et al.: Mounted Warfare. Cliodynamics 7:2 (2016) Figure 1. Map showing the chronological spread of cavalry across Afro-Eurasia. 23 Acknowledgments We thank Victor Mair, Pita Kelekna, Robert Drews, Nicola di Cosmo, Andrey Korotayev, and Nikolay Kradin for sharing their expertise in helping us to construct this chronology. Daniel Hoyer provided valuable comments and editing of the manuscript. References Anthony, D. W. 2007. The Horse, the Wheel, and Language: How Bronze-Age- Riders from the Eurasian Steppes Shaped the Modern World. Princeton: Princeton University Press. doi: 10.1515/9781400831104. Anthony, D. W. and D. R. Brown. 2011. “The Secondary Products Revolution, Horse- Riding, and Mounted Warfare.” Journal of World Prehistory 24(2–3):131–160. Baumer, C. 2012. The History of Central Asia: The Age of the Steppe Warriors. I. B. 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