A letter to the editor in today’s Boston Globe draws conspicuous attention by omission to the dirty little secret of the post-combustion energy argument. “Have we become so enslaved by the internal combustion engine,” writes Abington, Mass., resident Christina McMahon, “that we cannot envision a future free from petroleum?”

See, in Christina’s world, if we could just replace oil- and natural gas-burning electricity generation with wind power, solar power or whatever, we could be free of that nasty black goo forever and ever, amen. Unfortunately, that’s not even close to the truth.

It’s undeniably true that some of the petroleum we extract from the ground gets refined into gasoline and diesel to drive cars and trucks. But that’s not all we use petroleum for. Not by a long shot. We also turn petroleum into a number of different varieties of motor oil*. We refine it into kerosene which is used as jet fuel. Petroleum gets refined into asphalt which we use to make roads and parking lots and airport runways.

But that’s just the beginning. We refine petroleum into a clear, oily liquid called styrene. We polymerize styrene and turn it into a plastic called polystyrene. You know those plastic forks and knives you eat with at picnics and on airplanes/ Polystyrene. That plastic case that enclosed the CD you bought last week? Polystyrene.

Foamed polystyrene is called Styrofoam and is used as building insulation and packing material.

Probably the most widely used plastic of all is polyvinyl chloride, or PVC. It’s in everything from residential plumbing to electrical conduits to the dashboard in your car. Shrink wrap is made from PVC, and so are water bottles. Because PVC is nonreactive, it’s used to store human blood for transfusions. And that sexy, skin-tight outfit that chick in The Matrix wore? That was PVC, too.

PVC is produced from chlorine and ethylene. Chlorine is manufactured from saltwater, but you get one guess where ethylene comes from. That’s right: petroleum.

Automotive taillight covers are made out of a plastic called polymethyl methacrylate, or Plexiglas. So is the “glass” barrier that surrounds a hockey stadium. Large windows are made of Plexiglas, and so are aquarium tanks. Like PVC, Plexiglas is manufactured from ethylene.

Two varieties of polyethylene are found everywhere. Low-density polyethylene, or LDPE, is used to make produce bags, food storage containers and trash can liners, while high-density polyethylene (HDPE) is used to make milk jugs, detergent containers and plumbing fittings.

Polypropylene is used to make food packaging because its high melting point means it can handle the trip from refrigerator to microwave oven. And believe it or not, Australia makes their money out of it. Seriously.

Polyurethane is used in making tires and automobile seats. Expanding polyurethane foam is used as an insulating material. Liquid polyurethane is applied as a sealant to wooden furniture. Polyurethane with added polyethylene glycol makes spandex, which is both stronger and more durable than rubber. It literally revolutionized the athletic and swimwear industries.

Polyester and dacron fibers are made from a plastic called polyethylene terephthalate, or PET. Soft drink bottles are made from PET blended with polyvinyl alcohol.

My personal favorite is a little substance called polytetrafluoroethylene, better known as Teflon. Teflon was used during World War II to refine uranium for the atomic bomb, and keeps my scrambled eggs from sticking to the pan.

And then there’s Kevlar. What can we say about Kevlar? Five times stronger than steel, can withstand temperatures of over 750° without melting. It’s bulletproof and you can build a plane out of it. And it’s made from petroleum.

Believe me, people: It’s going to be a long, long time before we can even start thinking about a petroleum-free world. Oh, sure, if we stopped using petroleum to generate electricity, to drive our cars, to heat our homes, we’d have a lot left over to make CD cases and water bottles and Teflon pans. But we’d still need it. We’d still have oil wells and we’d still have refineries and we’d still have ignorant citizens of Abington, Mass., writing in to their local newspapers to bemoan the fact that we’ve been unable to free ourselves from that relentless, inescapable black goo.

(Good news for those of you who enjoy sex, though. Condoms are made from latex, a naturally occurring rubber found in the sap of certain plants. So when the oil crisis finally hits, someday, we can rest assured that our supply of Trojan Magnums will remain unimpeded. Assuming we can figure out some way to power the factory that makes them, and that we can somehow fuel the truck that brings them to us. Hmm. Maybe we’d better stock up after all.)