August 07, 2008

fuel from trees

Jatropha, sometimes referred to as the diesel tree, there's a fair amount of investment going into improving the yields.  You get the oil by way of seed processing.

Strangely, another species, copaifera_langsdorfii also shares the "diesel tree" moniker in many articles, but there are some big differences. The coolest being that you can get diesel fuel basically the same way you'd get sap from a maple tree: just tap it.

What sort of scares me about these trees is the wildfire danger.  Anyone who's ever had to put out a grease fire knows how bad they can be.  Imagine a plantation of grease fires the size of an apple orchard.  Considering that both species seem to favor tropical temperatures and aren't particular on soil quantity, I'm guessing there's a good chance we'll see a large farm of them on almost-desert soil go up in flames at some point.  It might only take one bad fire to blunt the interest in the crops.

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August 04, 2008

Becoming plants

As any computer scientist can tell you, evolution is awesome. Properly implemented as an algorithm, it can design aircraft, ships, trusses, antennas, just about anything that can be described with a "chromosome". So long as you have some notion of what a "good" design is, and a way to test for it, the genetic algorithm can usually make substantial progress in finding one, through many generations of reproduction, crossover, and mutation.

As an aside, genetic programming is an idealized version of the way we think biological evolution works. It's probably pretty close, and it can provide valuable insight into the evolution of species, but it's not the same thing. On more than one occasion, I've seen people point to GP as "proof" of biological evolution. It isn't, any more than a flight simulator is proof that airplanes can fly, and claiming it as such is a disservice to the work of archaeologists and evolutionary biologists.

Anyhow, in computer science terms, GP is a method of search. Though better than many methods at escaping local minima, it isn't perfect.  In a program, this could mean a set of populations that never produces a very good design, even after many generations.  There are parallels in biology.  Consider that the efficiency of plant photosynthesis tops out at just over 6%, and most plants are lower than that.  That amount of utilization is enough to power all the plant life on the planet, and it hasn't changed much in a long time.  Current solar panels already have that beat (10% to 20%). A plant species that could utilize solar energy at those rates would have a strong advantage over other plants in it's niche, and possibly beyond it. Whether the lower efficiency of plants it a fundamental limitation of DNA-based biology or simply "good enough" isn't the point; plants aren't as good at as we're becoming.

Humanity, near as we can tell, has a unique approach to competition among species. Intelligence, situational memory, and planning are only part of that approach, the merely physical and biological strengths that propelled us to early success. Symbolic communication -- facilitated by our intelligence -- led us to culture, to memories that survive individuals, and thus to complex technologies. With them, we became more than just hairless apes with cool hands and bad backs. We became, quite simply, better at evolving than any other complex animal.

Technology lets mankind be nearly mythological in power. We can communicate with each other across the globe. We have durable "bodies" that we can inhabit as needed that are stronger and faster than any animal that's ever lived, and allow us to explore any environment, even places where no other life may tread, largely with impunity. We've even created machines to do the boring parts of the very cognition that's made us so successful, so that we can do even more of it. As our powers have grown, so have our appetites. All the miracles we employ require energy, far more than our tiny bodies could possibly metabolize. So we built engines and motors, artificial metabolic organs capable of ingesting otherwise indigestible "foods" with incredible energy density, first coal and petroleum, later uranium and thorium.

All the "foods" we've found to feed our miracles, however, have limits and costs. They aren't depleted, by any means, but they aren't forever, and we can foresee a time when they may become so scarce as to be effectively gone. One possible, long term way out of this (barring some lucky breakthrough in fusion) is to become plants.

I don't mean that we should turn ourselves green (physically or metaphorically). We became what we are by being better than any other animal at literally everything they do, using technology to do so. To continue on our path, we have to find ways to be better than any plant at everything they do. Solar cells will be our leaves, spread out to catch the radiance of Sol. Batteries or other storage will be our sugars and fats.  Will it be enough power?  For a while, surely, and it will get us further along the way to whatever comes next.

I'd much, much prefer fusion, by the way.  We should still beat plants at their own game along the way, but fusion is nearly a necessity if we ever want to leave the solar system.

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July 20, 2008

How much methanol?

From NewEnergyAndFuel

To give some feel for this potential, a ton of wood would make between 165 to 185 gallons of methanol. The U.S. alone generates 240 million tons of wood waste each year, which would yield at least 39.6 billion gallons of methanol. U.S. paper mills could add another 9.3 billion gallons. The uncounted tons of trash and garbage would add still more. Methanol can be made from oil, natural, gas, coal and there remains more than half of the U.S. farm acreage that isn’t in production now that could add hundreds of millions of tons annually. Methanol can even be made from CO or CO2 with a hydrogen source made available.

I had thought that the yield was far lower, based on some other articles I'd read, but I was specifically looking at the Fischer-Tropsch process. I need to ask/look around and see how the author might have got to "1 ton of wood = 165 to 185 gallons of methanol".

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July 17, 2008

Nuclear Gas

This is old, but I promised myself an entry a day, so if you have haven't seen the Green Freedom plan, and you have a quarter hour to read an overview, have a look.

The idea is pretty simple: take normal octane combustion (qualitative equations, not balanced)
C8H18 + O2 => CO2 + O2 + Energy
and flip it on its head to get:
H2O + CO2 + Energy => C8H18 + O2

In the latter, you're basically storing the energy -- with some amount of inefficiency -- as C-H chemical bonds. So the plan is to build a buttload of new nuke plants and attach what amounts to an octane factory, using the output from the power plant to push the chemistry. Result: Air + Nuclear Power = Gasoline. No drilling, no change to our current autos, just good ol' gas. Downside? Getting the chemistry to work with proven methods puts a gallon produced this way at $4.60. Not much worse than a few places in CA these days, but basically not worth doing unless gas from petroleum stays as high as it's been for as long as it takes to build the power plants.

So why is this interesting? If any of the chemical steps in the process gets an upgrade -- a better catalyst, a shortcut across one or more steps -- the price could become more competitive. Further, building up something like this is probably a very good hedge against supply difficulties with OPEC or others. It also means that we aren't totally boned if non-food-feedstock biofuels don't pan out.

Though it's not nearly as fun as my idea for using a fleet of nuclear submarines to farm whales for their tasty meat and sweet, sweet whale oil.

Posted by: leoncaruthers at 10:02 PM | No Comments | Add Comment
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