I know, I haven’t blogged here in almost a year. It’s been a busy one: a new daughter, job interviews, attempting to finish my PhD, and flipping a condo on the side (into a down market, now that’s courage–or something). Nevertheless, I plan to keep this blog active and return to it in full force eventually. Before that day comes, though, here’s a small thought.
Just a few minutes ago, I was working on writing some computer code and doing unit conversions. I happened to think, “I wonder how much energy is really in the human diet?” So, figuring that we eat about 2,000 Calories per day (or kilocalories, with a small “c”), that works out to about 2.3 kWh.
At the rate I payed on my last electricity bill, that’s about $0.25 worth of electricity. That means that more energy is required to power a 100 Watt light bulb for 24 hours than to “power” a full-grown adult human being. An average house in the US requires around 40-50 kWh of electricity, with an occupancy of about 3 means that we each require more than 5 times our own energy needs just while at home. Add to that time at work/school and the imbalance reaches an order of magnitude.
And then, there’s the energy that we require for transportation. If the average American drives 12,000 miles at 25 mpg, then it takes about 25 kWh of energy just to haul us to school, work, soccer practice, and the grocery store.
Our manufactured goods contain tremendous quantities of embodied energy, or the energy that goes into their production. For that matter, so does our food. Viewed in bulk, the sum total of US energy production per capita is about 250 kWh. So, simply to provide for the needs of a being that requires a mere 2.5 kWh of energy per day, 100 times that amount is consumed by US citizens.
Yet the greatest joys in life, and those that sustain us and provide the most meaning, are the simple interactions we have with others. Our friends, our families, our children and spouses, and even our colleagues at work are those whom really deeply matter most of all.
To reduce our energy consumption, perhaps the biggest step we can all take is to turn off a few lights, turn off the TV and computer, and invite a few friends over. They’ll use less energy, and everyone will be a whole lot happier.
That is a very interesting point, it is interesting how our machines and devices, far less complex than the human body, takes more energy to accomplish much less. In a theoretical way, we are the ultimate “green machine”. You should update this blog more often, I think that you have a great many interesting ideas.
And Are you wife to Marlene Kandall who teaches at Drake High School? If so I am currently a student of her’s, the only reasons that I think it could be is she has talked about her little daughter, and she has your last name.
Best of luck!
Gray,
Thanks for your comment. For the last couple of years, updating this blog just hasn’t been a high enough priority for me. Who knows, that may change someday.
As to your question, nope, must be a coincidence there. Also, the spelling isn’t quite the same, my last name is “Kendall”.
I was thinking about this the other day and came to a slightly different conclusion. At 2.5kWH the energy density of my food seems pretty low. It costs me about 3 dollars to eat 2000 Calories whereas it costs only 25 cents for the same amount of electricity.
I’d be better off if I could eat coal. It has an energy density of 6.6kWH/kg. I would only have to eat 380 grams of coal a day to meet my energy requirements. That’s way better than the few pounds of food I have to eat.