Propane price a lesson in efficiency [UPDATED]Published 10:26am Wednesday, March 5, 2014 Updated 12:27pm Wednesday, March 5, 2014
All of our energy is biological in origin — a bacterial fermenting of vegetation from millions of years that we dug up, or drilled, or whatever. Everything that can grow can be fuel, be it wood, corn, beans, oats, switch grass, bales of straw, you name it. It all grew for one reason — the sun.
Here’s a fact for you: Every second, the sun loses 400,000 tons of its mass, as high energy hydrogen atoms change through fusion into helium atoms, and the yield gets to us as sunlight. No, it won’t be gone soon. Various estimates say it’s got enough for another billion years. (It’s really big.) Point: part of that sun’s energy is in the biomass that we burn.
Everyone with a propane (LP —liquified petroleum) gas furnace has been pretty upset over its price increase. What happened? An extremely wet corn and bean crop — way, way more moisture to bake out of that grain than normal so it could be stored without spoiling — and a pipe line that comes down from the shale fields in Canada that brings us propane that changed to oil.
And bam! Shortage!
About half of our propane comes from oil wells, and as soon as the Bakken field quits burning their gas off and starts collecting it, we’ll be better off. The other half comes from the refinement of oil into automobile gasoline.
But the big problem for any fuel like LP or natural gas that exists as a vapor at atmospheric pressure is storage. Natural gas remains a vapor as it is stuffed down into various old salt domes and salt mines and even into normal drinking water aquifiers across the United States. It remains down there as a vapor until we bring it back up. There’s a lot of natural gas, but storage is always the problem.
It’s never quite where we need it, which is the big problem across the board with any energy.
Propane, however, is compressed and stored as a liquid. Some of our stored propane comes from up in Mentor, Minn., where in the 1960s some business people bored 600 feet into the earth, into bedrock, and mined out a cavern in which to store propane under pressure as a liquid.
Propane turns into a liquid at more or less 70 psi, which is about twice that of the tires on your car. As a liquid, then, it comes to your tank at your home, then out of the tank as a vapor which your furnace can burn.
Information about the Mentor mine is scarce, because the Homeland Security folks are worried about terrorism. Basically, a hole six feet across was bored down 600 feet.
Rock drilling and crushing and moving equipment was then disassembled, lowered into the hole, reassembled by workers, and put to work. Rumor has it that most of that equipment is still down there.
They made a cavern that will hold somewhere in the neighborhood of half a million gallons of liquefied petroleum gas, which is then brought back up and delivered to our homes. There are other storage facilities all over, but most of them are man-made tanks. During the summer these storage facilities are filled up. During the winter, we take it back. Various amounts are predicted to be needed. If those predictions fall short? The price goes up.
Very quickly, here’s a cost comparison. Propane has come back down from $5 to just below $3. Divide 92,500 btu/gallon by 300 pennies ($3) equals 308 btu/penny. New gas furnaces convert this into heat at a 95 percent efficiency, so out of that 308 you get 293 btu for your penny.
Oil at $4 a gallon: 140,000 btu/gallon divided by 400 pennies equals 350 btu. Oil furnaces maybe (maybe) hit 80 percemt, so you get 280 btus for a penny.
Natural gas is up around $9.30 an MCF (Roman numeral “M” means a thousand.). So, a thousand cubic feet, at a 1,000 btus per CF, equals 1,000,000 btus divided by 930 (pennies), or 1075 btus per penny. Take this times 95 percent efficiency, you get 1,021 btus for a penny. We who live in the country wish we lived in town.
If you plug in any electric heater, you’re paying around 13 cents for a kilowatt-hour, which produces 3,400 btu. So, divide 3,400 by 13 equals 261 btu for your penny. Off peak is of course cheaper yet.
Five bucks a gallon for propane? Who’d have ever thought it could reach that.