Environmental Engineering Reference
In-Depth Information
3 How Much Energy Is Enough?
3.1 Scales of Consumption: From Mobile Phones to Space
Shuttles
On my first trip to New York, I felt a certain déjà vu. Everything seemed familiar, from the
crystalline office towers to the murky Hudson, not to mention landmarks such as the Statue
of Liberty and the Brooklyn Bridge. Looking out through the airplane window, I couldn't
help thinking about the amount of water and waste, goods and garbage, fuels and fumes
constantly flowing through the city. Later, when I found myself absorbed by the rushing
current of humanity that is daytime Manhattan, I witnessed up close a strange marriage of
entropy and order, as millions of people circulated in an area one-fifth the size of Malta. For
the first time, I sensed that large cities lose the human scale, and that what you see from the
plane is not that different from what you see on the streets: a flow of energy.
New York relinquished the title of world's largest city a few decades ago, and its tallest
towers are dwarfed by more recent constructions in Asia, yet it remains a symbol both of
the achievements and confines of urban development. An uninitiated visitor to New York,
Tokyo, São Paulo, or any of the mega-cities of the twenty-first century, might ask, how is it
possible that it all keeps going without ever running out of steam?
The answer is, thanks to gargantuan machines, the power plants tucked away out of sight,
just beyond the suburbs of these great cities. But what if, for some reason, those machines
suddenly stopped working and we were suddenly cast back into an age when human muscle
power was the principal source of energy? How much manpower would it take to charge
a mobile phone or to run a computer? What would it take to keep the lights on in Times
Square? We are so used to relying on external sources of energy that these questions seem
absurd, and yet to understand how we consume energy, we must first return to the human
scale.
Figure 3.1. Energy consumption per square meter in New York City. Because of the
heavy concentration of homes, offices, hotels, and shops in the most built-up parts of the
city, the energy requirements per square metre of land are extremely high, up to five times
the solar energy that strikes the ground. Source: Howard et al. ( 2012 ) .
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