When is a Plant not a Plant?

You’re probably aware that the US government is spending huge amounts of money to support production of biofuel. What they tell you is that this fuel will reduce our dependence on foreign oil and that it is better for the environment. It turns out, at least the way that biofuel is produced now, that neither claim is true. It takes more energy to produce the biofuel than it produces, and our topsoil is taking a beating. Add on top of that the finite amount of water that we’re pulling from wells across the midwest and ask yourself the question: would you rather run out of oil or run out of farmland?

Granted there are many plants that are much better candidates for creating biofuel than corn, the main crop used now, and even corn production could be made more efficient and less destructive to the soil. Still, perhaps it’s time to step back and look at the actual problem we are trying to solve. A better solution just might present itself.

What we are trying to do is make solar energy portable. Plants do that using photosynthesis — they put some carbon dioxide and some water next to each other and wait for a photon to whack the system just right, and out comes an energetic molecule, and some nice free oxygen to boot. It’s a pretty slick system. What we are doing now is using plants as solar collectors. We set them out in the sun, give them access to (lots of) water and carbon dioxide, and later we chop them down and collect the energy. Of course, the form of the energy isn’t quite right (sugars aren’t good fuel), so we have to process the result, using up some of the energy we collected.

The goal, then, is to turn sunshine into gasoline, alcohol, or some other handy hydrocarbon.

Flash back to when you were in grade school science class, watching a movie about how plants work. We zoom down into the animated land beneath the surface of the leaf where the magic is happening. A little wizard is hard at work, gathering the ingredients, then… at the critical moment he gawps at the camera, eyes round, and pulls a screen in front of his workbench. “We don’t know what happens back there,” the narrator says in his happy-narrator voice, “but what comes out is…” (I don’t remember exactly what comes out. ATP? You can look it up.)

Bumblebees. Photosynthesis. Great mysteries when we were kids, but not anymore. (Did no one mention to you that bumblebees can fly now? They have tiny horizontal tornadoes raging just above their wings. Sometimes the explanation is even cooler than the mystery.) Anyway, photosynthesis. Somehow, films made before DNA had been discovered still have us convinced that some things are unknown. I’m no photosyntholigist, but I only have to glance at wikipedia to know that the process is pretty well-understood today.

So I ask you: Do we really need the plant? We know how that stuff works, and we can reproduce it. Can we not create a solid-state device that captures solar energy and puts out an energetic molecule – the exact molecule we want as an end product? We could use such a device to create fuels with absolutely no impurities (no sulfur, for instance), and no net carbon footprint. The system does not have to be very efficient to easily outdistance existing plant-based methods, and it would use land that has much less value in terms of ongoing human prosperity. Farms could go back to growing food.

Picture a gas station on the highway between Los Angeles and Las Vegas. Behind it there is an array of dark panes stretched over the desert floor. From the array a pipe leads to a holding tank which holds the highest-quality gasoline money can buy. And the cost to the dealer is fixed – he just has to pay to maintain the system.

There would be environmental impact, of course. Vast tracts of desert would be shaded, and somewhat cooler as a result of energy being removed from the system. Although our machine would use a lot less water than a living plant, (or perhaps another source of hydrogen?), there would still be some demand. Overall, though, I think environmentalists would see it as a lesser evil.

I’ve been kicking this idea around for years, now, but apparently I haven’t ever written about it here. The plan is filed under get-poor-quick, but man, if anybody got something like this working, they could become some kind of ridiculously wealthy. As well they should.


9 thoughts on “When is a Plant not a Plant?

  1. Excellent article you wrote Jerry. Here in Kansas, biofuel was the hot topic a couple of years ago. Those problems that you mentioned are exactly right. I’ve heard numbers that the amount of diesel used to farm the corn was just slightly little less than the amount of ethanol produced per acre farmed. Then, fewer farmers were growing wheat so that they could farm corn and that was driving the wheat prices up. As land is taken out of circulation to grow fuel instead of food, the food prices go way up. Anyway, I want to read more of your thoughts on this topic.

  2. In some instances, a “plant” is the person there in the group to spy on you….this was described to me by a former Eastern Bloc psychiatrist who said that the first task of the group in group therapy was to find out who among the patients in the group, was the government “plant”.

  3. A few more thoughts. In my area there is a company, Novozymes, working on ways to convert native switchgrass to ethanol. Switchgrass being way less intensive to grow – it’s a weed – that you would not end up with a net negative like you do when converting corn. They got a PR visit from Bush not long ago, around the tail end of his presidency, but I’ve heard nothing since. Plant fibers and cellulose are such a bitch to process. Gives you new respect for termites and such. Brazil is supposedly doing well with ethanol because it is so easy to grow sugar cane there.
    I still like you idea, but the economists love to say TNSTAAFL (there’s no such thing as a free lunch). I wonder how water intensive your future idea is. I’m no chemist, so it is just speculation, but I imagine there would have to be lots of water used in converting CO2 and sunlight into gasoline.
    Finally, just when you think that it is so hard to harvest sunlight you run into a paper napkin calculation like this one at realclimate.org. I wish I could insert their figure on how much global area is needed to produce the world’s electricity needs, but it is astoundingly small. I will put link at end of my comment, but the link is a response to a chapter in the new Superfreakonomics book that concerned GW. I read and enjoyed Freakonomics. Have not read the new one, but the GW chapter left a bitter taste for climate scientists. The realclimate.org response is a scathing open letter to one of the authors. There is no need to read the whole thing, just scroll til you get to the picture of earth and then read the prior paragraph. (The whole thing is fun, and scathing, but not relevant to your post).
    Here ’tis: open letter to Steve Levitt

    • I’ve thought about the water thing, and it’s definitely an issue. The hydrogen in the hydrocarbons has to come from somewhere, and water is the obvious choice.

      While it would take a lot of water, it would be a lot less water than a plant (any plant) uses to create the same amount of energy. If the water were used efficiently, it would probably be within an order of magnitude of 1 gal water => 1 gal hydrocarbon-based fuel.

      And there’s nothing that says that sea water can’t be used – if necessary just add the solar still module next to the hydrocarbonificator module. Baja California – the next energy mecca?

      Certainly this is not a free lunch any more than photovoltaic cells are – there would be environmental fallout from creating so much shade, for instance. There would probably be a huge up-front investment; the challenge is to make a system that pays itself off eventually. Once the thing was up and running reliably and you were reconciled to the new ecosystems emerging in desert shade, and reduced hunting range for owls and eagles and the like which like to see their prey from above, the cost of the lunch could be pretty low.

      For a long time photovoltaic cells were a false free lunch – the energy to make a cell was more than it would collect in 20 years of operation. Once you cross a threshold, however, photovoltaic makes a good investment. This would be similar – technology has to advance to where the return on investment happens in the lifetime of the original investors.

      A lot of the issues with something like this are similar to photovoltaic. The main difference is the output – rather than electricity you get a more portable, storable energy format. If it takes three times the collection area to get the same net energy as photovoltaic, that’s not really a problem, since you can put your collectors anywhere and move the energy with much less loss.

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