When most people think about the cost of energy, the focus is on commodity based pricing—either from a seller’s point of view, or as an end user receiving an electricity or gas bill. There are a growing number of people focusing on the non-economic impacts of energy production and consumption, but that’s an article for another day! Appropriately, the seller or buyer of the commodity focuses on the cost per energy unit, such as dollars per BTU or dollars per kilowatt hour. Researchers like myself who focus on the creation of fuels from subsurface resources using indigenous microorganisms often take a different perspective on the cost of energy, one that focuses on the number of molecules of an energy yielding compound that we can coax out of microorganisms in a given time. So for a different perspective on energy, I wanted to review the cost of compounds we as a society purchase and/or consume from a “per molecule” perspective. Let’s start with natural gas. Assuming natural gas is 100% methane and the pricing is $5 per thousand cubic feet (MCF), one would be purchasing 1.44X1026 molecules of methane per dollar. I asked around the lab for examples of extremely inexpensive pure chemicals to compare to methane on a molecule per molecule cost basis. One of the first answers was table salt (NaCl), which on a molecule basis happens to be about 8.5 times more expensive than natural gas . Anybody think Aspirin is inexpensive? On a per molecule basis, Aspirin is 8600 times more expensive than natural gas. Of the examples we looked at, the top of the leader board was gold, which not surprisingly is about two million times more expensive than natural gas! The fourth example is gasoline. While not a pure compound, we used an average component of gasoline for the calculations. At $3 per gallon, a molecule of gasoline is 26 times more expensive than a molecule of natural gas. The last example is water. Household pricing for water is around $4.68 per 1000 gallons, meaning that household water is actually 190 times less expensive per molecule than natural gas.
So what’s the point? For starters, on a molecule by molecule basis, energy commodities are pretty inexpensive relative to most other things we purchase. The sole exception we presented was water. While I don’t foresee this fact keeping people up at night, for those of us that are farming energy commodities one molecule at a time, one microorganism at a time, the price per molecule is a heavy burden.
Gary Vanzin, Ph.D
Luca Technologies Inc.
 Assume 1 MCF = 1198 moles of methane, use Avogadro’s number to convert to molecules.
 Assuming $0.60 dollars per kilogram of salt, one dollar buys you 1.71 X1025 molecules of salt.
 Assuming a $10.00 bottle contains 500 grams of pure acetylsalicylic acid, you’re getting 1.67E1022 molecules per dollar.
 At $45 per gram, you only get 6.83E1019 molecules of gold per dollar.
 Assuming gasoline weights 105 grams/mol and has a density of 0.75, you buy 5.42 E1024 molecules per dollar
 2.70 X1028 molecules of water per dollar at 55.55 moles/liter and $4.68 per 1000 gallons.