Friday, October 18, 2013

Centralization and Network Effects: Energy and Power

The fundamental governing principle of life is that time and energy are limited. Life boils down to energy, and the expenditure of energy--the physical quantity of energy expenditure is power, or energy per unit time. For most animals--people included--the ability to generate mechanical power is limited by physiology, which in turn limits the amount of oxygen that can be delivered to muscles per unit time.

Game Trail in Northeast
Ohio Woods
Various patterns emerge from these limits, for example, if you walk through the woods in Ohio, you'll find numerous game trails, which are basically roads made by deer. The deer follow the tracks of their friends and wear a narrow path between sources of food, water, and shelter. If you follow these trails, you realize, quickly, that the physical capabilities of deer are a lot different than people. Rather than following the gentle slope of a hogback up from a stream, for example, a deer path will go directly up an earth wall.

Sometimes you'll find trails that are made by pedestrians which cut through fields, or small stands of trees, or cut across a lawn. These trails exist because it is easier--that is, less energy intensive--to get from point A to point B using them, rather than bushwhacking a new trail, or following the orthogonal roads or sidewalks, and making the walk 41% longer. In a pastoral world, these human trails crisscross the landscape, however, in an industrial society, only small segments of these trails connect roads.

In an industrial society, machines overcome the limitations of human power production. The energy that's stored in a cup of gasoline exceeds the amount of energy stored in a cup of food by orders of magnitude, for example 31,500 calories versus 320 calories for a cup of ice cream. The power that's produced by a machine is, again, orders of magnitude larger than the power that's produced by people. A typical healthy young man can produce less than 200 W for a long time. A 5 hp lawn mower engine produces 3,728 Watts as long as the tank has gas.

Within a city or town that grew in the industrial era, roads are shaped by geometry and plans, because machines make it possible to shape the landscape, and there's a reciprocal relationship between the machines: the trucks and cars and bulldozers, and the roads. That is the roads must be large enough to carry a truck, because the trucks must be large enough to carry the machines to build the roads.

However, the human imposed geometry generally disappears at the city limits, and the roads linking cities and towns are more like deer trails.

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