I drive a truck, of all possible glamorous occupations, and I almost always haul scrap metal. Very thick metal, like railroad rails and bulldozer parts, will go to certain destinations. More common scrap-- such as cars, washing machines, and that steel sheet found on modern barns-- goes to places that have scrap shredders.
A shredder is a large structure, with engines supplying thousands of horsepower to turn a massive rotor approximately eight feet wide, which is lined with dozens of swinging hammers weighing a couple hundred pounds each. After being battered into fist-sized chunks, the scrap is sent to conveyors and magnets and such, with the end result being three piles: iron and steel (ferrous metal), non-ferrous metal (like aluminum and copper), and "fluff" (everything else). Fluff contains seat cushions, rubber, glass, plastic, dirt-- anything that doesn't conduct electricity. So, yes, some parts of it are fluffy, but it wouldn't be very comfortable.
Some materials are not acceptable to be shredded. Actually, there's quite a list, though some of the banned items are winked at. Lead-acid batteries (like in your car) are forbidden, as are the large capacitors that serve microwaves and fluorescent lights-- unless a label says they are free of PCB's. Cars must be drained of their oil and coolant, and stripped of as many tires as possible. Propane and gasoline tanks are strictly forbidden. It doesn't take a lot of imagination to picture what bad things might happen to a volatile fuel container suddenly ripped apart in a shower of sparks. I haven't seen a bad one, but I hear that the fires can be impressive.
Now, since I've been hauling junk most every day for the last sixteen months, I've seen quite a few things junked that I was sad to see go. Classic cars, still-good equipment from Kodak and Xerox, useful truck components, farm machinery from the first half of the 20th century-- all sorts of things. Some smaller things can be saved-- indeed, over half of the hand tools that I carry in the truck were rescued. Sometimes, though, the metal recycling business just breaks your heart.
Yesterday was one of those times. Yesterday was the worst ever.
I had unloaded my 9 or so tons of various shreddable scrap, received my paperwork, and already begun to drive away... just like any other day, going past the shredder. There was another big truck backed in, and the grapple crane had pulled a car out of that truck, wending its way through to air toward noisy and brutal destruction.
Something about the tail of the car caught my eye instantly. It was a small car, but the trunk looked a bit too narrow, and that set off mental warning bells. Next, my eye swept over the rear fenders-- or, perhaps, the lack of fenders. The car featured a smooth cover over the top half of the rear wheel, and no fender bulge at all. No, I thought, it couldn't be...
And then I looked at the wheels. Those unique aluminum wheels, with a design that reminds you of a printed circuit board.
No! ...but it was. It was an EV1, the completely electric car designed by AreoVironment and General Motors. Among other feats, the most aerodynamic production car ever.
After seeing the innocent vehicle swung to its doom, I spotted one of my friends who works at the facility. I parked the truck, grabbed my hard hat, and hopped out. My associate was familiar with the EV1, it seems, because they get them coming in to shred "all the time." That entire truckload was nothing but EV1's. Aah! Not much steel in them, he said. Aluminum, copper, fiberglass, and such. The situation seemed odd, so I inquired if they were legally barred from salvaging from the EV1's.
Sure enough, there was a guy from GM sitting in a Saturn SUV, watching. The scrap guys weren't allowed to remove a car from that truck unless it went directly into the shredder. Because, you see, every EV1 is owned by GM, and only leased to drivers. Apparently, the car is considered to be an engineering test, and now they're being destroyed. Here's GM's "lessons learned" page about the EV1 project.
Now, normal cars have to be stripped of a lot of things, but these still had the tires on, which made me wonder. What could or couldn't be shredded? What might or might not still be in there? He did list copper, after all, and copper... Oh, no! So, I asked if the motors and such had been removed, and they were just shredding the hull.
No, he said, "they have the motors in them." Egad. "They have everything in them."
Now, I can only recall so much as the car's detailed specifications, but that's a hundred-plus horsepower three-phase electric motor, with three inverters to run it from the battery, no doubt rectifiers to recharge the battery... and, if they're OK to shred, half a ton of nickel-metal hydride batteries.
After I learned about the guts of the EV1, a couple-few years ago, I immediately drew up a plan for a hybrid diesel-electric heavy truck-- based on the motor from an EV1, because I knew its basic specs, and it seemed decent for the job. Of course, I would never be able to get my hands on one, but at least my plan called for a device that I knew to exist. It's not easy to find electric motors that large.
Such a waste. A horrible, awful waste. I, no doubt among other people, would pay thousands of dollars for the innards of that car. Heck-- there might be enough people willing to outbid me that there wouldn't be enough EV1's to dismantle for me to afford one.
Smash! Rumble! Rend!
Or that next car. Crash! Destroy! Or that one...
Having received a request for more science (and, indeed, for new material of any sort), I decided to go to CNN.com and see what was new. And the first thing I found was:
MINNEAPOLIS, Minnesota (AP) -- Researchers say they have produced hydrogen from ethanol in a prototype reactor small enough and efficient enough to heat small homes and power cars.
Now, I applaud their ingenuity, and I favor hydrogen as the energy carrier molecule of the future. But... extracting hydrogen from ethanol as a source of energy is so utterly wrongheaded...
Wanting evidence to back up this article (which I had planned to be a righteously indignant slam of ethanol energy), I performed a quick Google search for ethanol corn energy production. I was quickly reassured that I was not the first person to look at the matter with a critical eye. By the end of the investigation, however, I had found that ethanol energy is more complicated than it seems.
Firstly, let's lay some groundwork. Ethanol-- a.k.a. grain alcohol, a.k.a. drinking alcohol-- is commonly produced from sugary or starchy feedstocks, via fermentation by yeast. The molecule is made up of two carbon, six hydrogen, and one oxygen atoms. That oxygen is related to why ethanol contains less energy per unit volume than gasoline, but also has a higher octane rating, and results in less carbon monoxide when burned. Ethanol is corrosive, and has an affinity for water, both of which make it more troublesome in gasoline blends than the competing oxygenate MTBE. (Though MTBE has political problems.)
Ethanol is an example of biomass energy, meaning that the fuel comes from living things. Modern living things, that is-- fossil fuels came from biomass originally, but their ancient origin sets them apart. Biomass energy seems like a convenient way to harness the power of the sun cleanly and efficiently, but the reality isn't as tidy-- and ethanol is the worst offender.
Every discussion of this issue seems to bring up Dr. David Pimentel, of Cornell University, who claimed that "about 70 percent more energy is required to produce ethanol than the energy that actually is in ethanol." He is rather quotable, what with statements like "Abusing our precious croplands to grow corn for an energy-inefficient process that yields low-grade automobile fuel amounts to unsustainable, subsidized food burning." (Press release here.)
The National Corn Growers Association fired back, insisting that ethanol energy was a net positive by 29%. Apparently, Dr. Pimentel had used some outdated numbers. A forgivable error, since his work with the Department of Energy was two decades ago-- but a fairly stupid one, as errors go. Dr. Pimentel's newer paper puts ethanol at a net energy loss of 29%. Naturally, most of that input energy comes from fossil fuels-- which would then seem to make ethanol useless... more on that later.
No matter which numbers you use, it clearly takes a lot of energy to produce ethanol-- and that's completely ignoring the energy input from sunlight. Why is that? Well, I'm glad you asked.
Commercial ethanol fermentation currently requires high-quality starchy feedstocks, and that means grain (the overwhleming majority comes from corn). Growing corn involves the use of large amounts of nitrogen fertilizer. Current forms of nitrogen fertilizer require a disturbing amount natural gas to produce. There are other energy costs in corn production, such as equipment fuel, but fertilizer is the big one.
There are many energy costs at the ethanol plant as well, but there is again a single large one-- that being heat for distillation, which is generally supplied by coal. Separating ethanol from water is what we scientists call "a pain." Three distillations isn't enough, in fact, and you have to resort to other tricks to get most of the remaining 5% water out.
Ethanol from corn will never be a stunningly efficient energy carrier molecule. There is a catch to all of the doom and gloom, though. Note that most of the input energy is from natural gas and coal-- both of which are extracted in large quantities in the United States. Ethanol is actually a way of transforming US fossil fuels into a liquid fuel for vehicles. It does, in fact, decrease US dependence on foreign oil-- just by a small amount.
But at what cost? Growing corn requires intensive agriculture, which has its own environmental concerns. As a former farmer, I won't tell you that growing corn is horrible, but that doesn't mean I think we should go out of our way to grow it for dubious purposes. Ethanol production involves burning coal (or natural gas, or #6 oil). Environmentalists, as a group, hate both agricultural runoff and burning coal. Thus, logically, environmentalists should vigorously oppose ethanol from corn.
It is often said that the US government's subsidization of ethanol is at least good for farmers, since it raises the price of corn. This is misleading. True, it does raise the price of corn-- but that's bad for farmers who use corn, which is nearly every farmer with animals. Comsumers of food pay higher prices either way. You're being taxed for the honor of paying more for corn-shelled, meat-filled tacos. Feel free to complain to your US senator, or to the infamous Archer Daniels Midland Corporation. Cecil Adams certainly gave ADM the treatment when he talked about ethanol.
Why do I keep specifying ethanol from corn? Well, that's because nice, starchy corn isn't the only possible feedstock for ethanol. But that's a topic for another day-- especially since such other sources are not yet ready to compete.
Speaking of alternative fuels (tm) to be discussed in my next such article, it turns out that today is National Biodiesel Day. It's Rudolf Diesel's birthday, you see. Of course, I seem to recall that Rudolf's original engine ran on coal dust, but that's just splitting hairs. =) Come on, smile.
Considering that the Wright brothers were bicycle builders, you'd think that they would have put wheels on the plane, you know? :-)