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World Futures: Efficiency (Part Three)

on August 11, 2017 - 7:08am

World Futures: What Do We Need?

Los Alamos World Futures Institute

In the previous column, the implied conclusion was that humanity should convert to solar power for everything it does, both mechanically and biologically. But what does this really mean and HOW (the really hard part) do we do it? Energy consumption for humanity is driven by humanity itself. Let’s consider what this means.

A human being is, energy-wise, the equivalent of a 100 watt light bulb. That is, we consume and emit on average about 100 watts of power (at 100 percent efficiency) or 1 KwH (Kilowatt Hour) every 10 hours or 2.4 KwH per day. Hey, this is getting complicated quickly – actually an insight into the problem of solar power adoption. With a world population of 8 billion people (actually 7.5 billion – but we are estimating), this is the equivalent of 19.2 billion KwH per day. Now assume that human beings are machines that can run on gasoline at 100 percent efficiency.

A gallon of E10 gasoline has about 32.78 Kw of energy available. If you divided 19.2 billion KwH per day by 32.78 KwH per day per gallon, you need 0.585723 billion gallons of gasoline per day. At $2.50 per gallon of gasoline, this amounts to $1.46 billion per day or about 19 cents per person.

Clearly, we cannot consume gasoline.  We are human beings, not machines. Instead, we buy groceries or grow them ourselves at a cost of more than 19 cents per person per day. This is an extra cost we deem essential because of our perception of value. And we tend to measure efficiency in economic terms.

Above we equated people to light bulbs, so let’s look at the light bulb itself.  In simple terms, there are three kinds of light bulbs – incandescent, fluorescent, and white light emitting diodes. Historically, we used incandescent bulbs and mentally correlated wattage to light emitted (brightness). You “know” how bright a 60 watt incandescent bulb is.  The efficiency of a 60 watt incandescent light bulb is about two percent – even while consuming 60 watts of power every hour, only 1.2 watts of light energy is radiated each hour.  

As humans in our everyday lives, do we really care about this? NO. We care about one electricity bill each month and can we afford it? If you rent and electricity is included, you are still paying for it, but “couldn’t care less.”

As a comparison, consider a light emitting diode bulb. I went online and found 60 watt incandescent bulbs for $2.24 each. A dimmable l.e.d. equivalent bulb was priced at $2.38 each or 12 cents more per bulb. How long will it take to economically break even using the l.e.d. bulb? While you might say “who cares? 12 cents is in the noise,” the analysis has greater value than 12 cents.

In comparing the bulbs, one consumes 60 watts per hour while the other uses only 9 watts per hour or a 51 watts per hour savings (greater efficiency). If electricity costs 11 cents per KwH, 12 cents represents 1.1 KwH and provides a breakeven point of 21.4 hours of use, or less than two weeks at two hours use per day.

In contemplating and working on this specific column, I explored the idea that if every human being could personally consume one less watt-hour of energy per day, this is the equivalent of 250,000 gallons of E10 gasoline per day. Assuming every human being has a 55 inch l.e.d. television set (perhaps an absurd assumption but it permits some simple math), if each person individually watched only one minute less TV per day (and turned the set off), we could save the equivalent of 250,000 gallons of E10 gasoline per day.  Or, if we used solar power, we could watch more TV. Stay tuned for part four….

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