The energy needed to deliver energy has always been a concern for societies. ‘All our societies require enormous flows of high-quality energy just to sustain, let alone raise, their complexity and order (to keep themselves

[ . . . ] far from thermodynamic equilibrium) … [and] after a certain point in time, without dramatic new technologies for finding and using energy, a society’s return on its investments to produce energy […] starts to decline’ (Homer-Dixon 2006:54–55). An example is the Colosseum in Ancient Rome. Construction began under Emperor Vespasianus between 72 and 75 CE and inaugurated in 80 CE by his son Titus, with a hundred days of games and some ten thousand beasts being killed. An estimated million ton of raw material have been moved for its construction. An estimated 185 TJ of energy was needed. Over 75 percent of it was used to feed the thousands of oxen engaged in transporting materials. The remainder powered the human labourers: Over 2,000 people working 220 days a year for 5 years. During this period, some 55 km2 in the largely agrarian economy was needed to deliver this solar energy.

Compare these numbers with ships carrying what has been called the ‘greatest invention of the 20th century’ and an icon of uniformity and globalization: the container. The largest container ships measure 400 m in length and over 12 m in depth and can carry 15,500 containers of 36 m3 content or 56,2000 m3 of freight. Their normal speed is 46 km/hr, so the kinetic energy of only the freight is equivalent to 46 GJ at an average freight density of 1,000 kg/m3. With a 10 percent speed reduction, fuel use drops with a quarter, which means about 250,000 ton/yr less of CO2-emissions. The next round of upscaling is to ships of 18,000 containers, which are expected to be profitable because they carry more freight but at lower speed. The builders claim a further reduction in CO2-emission, to 3 grams per ton-km of freight. At present, Rotterdam Harbour can handle 100,000 containers/week and is among the few harbours that are deep enough for such ships (NRC 18 March 2011). The trend is an even larger scale of operations in the name of lower cost and lower emissions.

Literature

Homer-Dixon, T. (2006). The upside of down: Catastrophe, creativity, and the renewal of civilization. Island Press, Washington