Sunday, May 17, 2009

Let's Get Real About Energy

This is a rather good and eye-opening article. It gives, in very simple terms, the level of energy consumption using comparison that many people can understand.

Let's express energy consumption and energy production using simple personal units, namely kilowatt-hours. One kilowatt-hour (kWh) is the energy used by leaving a 40-watt bulb on for 24 hours. The chemical energy in the food we eat to stay alive amounts to about 3 kWh per day. Taking one hot bath uses about 5 kWh of heat. Driving an average European car 100 kilometers (roughly 62 miles) uses 80 kWh of fuel. With a few of these numbers in mind, we can start to evaluate some of the recommendations that people make about energy.

These are numbers that many people can understand. But what is also interesting is the comparison of various possible alternatives energy sources.

As a thought-experiment, let's imagine that technology switches and lifestyle changes manage to halve American energy consumption to 125 kWh per day per person. How big would the solar, wind and nuclear facilities need to be to supply this halved consumption? For simplicity, let's imagine getting one-third of the energy supply from each.

To supply 42 kWh per day per person from solar power requires roughly 80 square meters per person of solar panels.

To deliver 42 kWh per day per person from wind for everyone in the United States would require wind farms with a total area roughly equal to the area of California, a 200-fold increase in United States wind power.

To get 42 kWh per day per person from nuclear power would require 525 one-gigawatt nuclear power stations, a roughly five-fold increase over today's levels.

A very good article.


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