Energy Unit for Global Use

Very large powers of 10 occur in the wide-spread discussions of 

Annual energy consumption is dimensionally power, and a good unit of power is a 60 W continuously burning light bulb. (One could make it a 100 W bulb, but that is a slightly less modest unit). Furthermore it makes sense to express the power per capita of the world population, and one then arrives, typically at Table 1. 

Food consumption by an individual could be a starting point at 300 kcal day or 3 kWh day or 120 W, which is two light bulbs. This has to be multiplied by 16.5 to allow for the individual s share (on average) in roads, factories, cars, etc. Table 1 shows at once the low average efficiency of photosynthesis, so that there is scope for the development of high energy-yielding crops. 

Total sea area Total surface area (71 % of total) 36 51 

Year Population Yield (60 W bulbs p.c.) Requirements from Table 1 (60 W bulbs p.c.) 

---