Energy

Since I’m having a low energy day, I’m playing with numbers again. The DOE energy conversion page still rocks my world.

The last time I did this, I determined that heating, lighting, and otherwise making my house “go” last year took 4.4e6 BTUs of electrical power, plus 1.6e8 BTUs of fuel oil power. We’ll just assume that the fireplace was somewhere well below that. That’s 1.6e8 BTUs.

I also drive. Assuming perfect conversion, gasoline yields 1.24e5 BTU per gallon. So, a tank of gas (20 gallons) gives us something like 2.5e6 BTUs. That’s disturbingly close to my annual electrical consumption. In fact, to match my ANNUAL electrical consumption requires about 35 gallons of gas. Yikes. Almost two tanks. 4 round trips to Boston.

Matching my total home energy consumption just by burning gasoline would require something like 1290 gallons of gas. That seems like a lot, until you factor in the amount of time we’re talking about. In an average week, I fill up my tank once. 52 weeks times 20 gallons = 1040 gallons. Yikes! In big, sweeping generalizations, I use about the same amount of power to move my car around as I do to heat and light my house! Makes me want to start tracking my actual gasoline consumption … which would allow me to add another page to my growing Spreadsheet of Obsessive Compulsive Doom.

My planet destroyer gets about 16MPG on a good day. 16 * 1040 ~= 16,000 (duh). I’ve had the car for 5 years, which if this is relatively close, puts 80,000 miles on it. In reality, it’s got 70,000 … however, I was able to ride my bicycle to work for spring, summer, and fall of four of those years. The numbers are not off by an order of magnitude … which is about the right accuracy for this sort of thing.

Car = house in terms of annual energy consumption. Holy hell.

In more entertaining numbers: The internet claims that one “dietary” calorie is 1,000 “physics” calories. So a Snickers bar has an energy content of 250,000 calories. A dietary calorie is (according the to same page) equal to around 4 BTU. That gives me 1,000 BTU per Snickers bar, a beautiful, round number. A snickers bar is about 2 oz. Setting aside all pretense at using the numbers correctly, assuming that gasoline weighs the same as water, that fluid and mass “ounces” are interchangeable, etc, etc, We could claim that a “gallon” of snickers is around 64 bars. Bear with me. Think of a case of 64 snickers bars. It’s about the same size and weight as a gallon of gasoline.

64 bars = 64,000 BTU. 1 gallon of gasoline = 124,000 BTU. So, gasoline is about twice as compact a form of energy as a snickers bar, which is after all mostly organic fats. Not too bad, not too bad.