[CNN] Commentary: Let's get real about alternative energy

[sjinhan]

http://www.cnn.com/2009/TECH/science/05/13/mackay.energy/index.html

(CNN) -- We need to introduce simple arithmetic into our discussions of energy.

We need to understand how much energy our chosen lifestyles consume, we need to decide where we want that energy to come from, and we need to get on with building energy systems of sufficient size to match our desired consumption.

Our failure to talk straight about the numbers is allowing people to persist in wishful thinking, inspired by inane sayings such as "every little bit helps."

Assuming we are serious about getting off fossil fuels, the scale of building required should not be underestimated. Small actions alone will not deliver a solution.

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.

Take, for example, the idea that one of the top 10 things you should do to make a difference to your energy consumption is to unplug your cell-phone charger when you are not using it. The truth is that leaving a phone charger plugged in uses about 0.01 kWh per day, 1/100th of the power consumed by a lightbulb.

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In Depth: Commentary

This means that switching the phone charger off for a whole day saves the same energy as is used in driving an average car for one second. Switching off phone chargers is like bailing the Titanic with a teaspoon. I'm not saying you shouldn't unplug it, but please realize, when you do so, what a tiny fraction it is of your total energy footprint.

In total, the European lifestyle uses 125 kWh per day per person for transport, heating, manufacturing, and electricity. That's equivalent to every person having 125 light bulbs switched on all the time. The average American uses 250 kWh per day: 250 light bulbs.

And most of this energy today comes from fossil fuels. What are our post-fossil-fuel options?

Among the energy-saving options, two promising technology switches are the electrification of transportation (electric vehicles can be about four times as energy-efficient as standard fossil-fuel vehicles) and the use of electric-powered heat pumps to deliver winter heating and hot water (heat pumps can be four times as energy-efficient as standard heaters).

Among all the energy-supply technologies, the three with the biggest potential today are solar power, wind power and nuclear power.