Saturday, April 28, 2007

Did you know? Part 2.

Last night, I got to use this factoid at a dinner. Upon hearing that diesel vehicles have a fuel efficiency of 1 mile per chicken, people immediately wanted to know what the fuel efficiency is in terms of human fat. Last December, I read that a company in Norway struck a deal with a hospital in Miami to supply it with 3,000 gallons a week of liposuction fat for conversion into biodiesel. In the article, it says that 3,000 gallons of liposuction fat is enough to make 2,600 gallons of biodiesel. The average diesel engine gets about 30 miles to the gallon of #2 diesel. But biodiesel (in pure form) gets 10% lower fuel efficiency relative to traditional diesel fuel (source). So, an average diesel engine will get say 27 miles to the gallon of pure biodiesel. 3,000 gallons of liposuction fat = 2,600 gallons of biodiesel = 70,200 miles driven. So, 23.4 miles per gallon of liposuction fat.

But that's per gallon, not per pound. Body fat has a density of 0.918 grams per cubic centimeter (source). There are 453.59 grams in a pound and there are 3,785.41 cubic centimeters in a gallon. Thus, a gallon of liposuction fat would weigh 7.66 pounds. And 23.4 miles per gallon would translate into 3.05 miles per pound.

As an additional sanity-check here, diesel fuel typically has an energy density of 40.9 MJ/L (source). There are 3.785 liters in a gallon so 40.9 MJ/L equals 154.8 MJ/gal. If a diesel engine gets 30 miles to the gallon, it takes 154.8 MJ to go 30 miles. A pound of human fat contains 3,500 kcal (source). A kcal contains 4.184 kJ of energy so 3,500 kcal would equal 14,644 kJ or 14.644 MJ. If 154.8 MJ goes 30 miles, 14.644 MJ would only get you 9.46% of that distance - or 2.84 miles.

In terms of the difference between 2.84 miles per pound of liposuction fat vs 3.05 miles per pound, one thing to keep in mind is that some of the energy content of biodiesel comes from the alcohol component of its production (typically methanol). So the 2.84 figure is probably more accurate than 3.05.

Regardless, that’s too much detail for casual conversation. The short answer is that the fuel efficiency of a diesel engine is about 1 mile per chicken or 3 miles per pound of liposuction fat. Use that factoid at your next cocktail party and let me know how it goes. =)

If you really want to impress your guests, you could also mention that according to the American Society of Plastic Surgeons (ASPS), 325,000 of liposuction operations were carried out last year to remove fat from various parts of the body - particularly the thighs, abdomen and buttocks – and that the average woman sheds an average of 20 pounds of abdominal fat by liposuction (source). So, 325,000 operations x 20 pounds per operation = 6.5 million pounds of liposuction fat. At 3 miles per pound, 6.5 million pounds of liposuction fat would get you 19.5 million miles. And, at 30 miles per gallon, that would offset 650,000 gallons of diesel fuel. Unfortunately, the US consumes about 64 billion gallons of diesel a year - 100,000x the amount you could get from liposuction fat. But every little bit helps and Americans get fatter by the year so perhaps this will make more of a dent over time. =)

Monday, April 16, 2007

Sacrifice

My sister-in-law HG sent me this quote by Joseph Smith regarding sacrifice: “A religion that does not require the sacrifice of all things never has power sufficient to produce the faith necessary unto life and salvation." It's a high standard and it should be. But it's also what keeps me from affiliated myself with a specific belief system and organization - at least for the time-being. There are a variety of mostly little things that I'm just not willing to sacrifice. Taken individually, my objections would likely seem petty but taken together they're currently a big barrier for me to overcome.

Did you know?

Today, ConocoPhillips and Tyson Foods announced a partnership to make "renewable diesel" fuel from animals fats. In a WSJ article about the partnership, it says:

Tyson produces about 300 million gallons of beef, pork and chicken fat each year … Producing one 42-gallon barrel of renewable diesel requires about one barrel of animal fat. And each barrel requires, on average, two steers, or 16 hogs or 1,300 chickens, Tyson officials say.

So, it takes 1,300 chickens to get one barrel of diesel fuel (via their proprietary process). One barrel is 42 gallons. So that’s 31 chickens to generate one gallon. At around 30 mpg fuel efficiency, that’s one chicken per mile.

So, your “did you know” fact of the day is: you can drive one mile on the fat of a chicken. Therefore, diesel vehicles have a fuel efficiency of 1 mpc (1 mile per chicken). Go ahead and use that at your next cocktail party as an icebreaker. =)

Saturday, April 14, 2007

Disposable income

My 5-year old JD made his first major purchase recently - a Razor scooter. He spent $30 that he saved up across various birthdays and holidays. It's amazing that he's old enough to start making decisions like this. So far, he hasn't pulled the trigger on the credit card offers he's received in the mail. =)