over the cliff, onto the rocks.: Grainy math

Thursday, April 24, 2008

Grainy math

Speculation is/isn't driving up your food prices and mine, and we can't grow enough ethanol to power the US, let alone the whole world.

Just out of curiosity, I did some back-of-the-envelope calculations [no, I'm not going to show my work]. Last year the world produced enough grain and soybeans [I didn't use any other foodstuffs in my calculations] to feed every man, woman, and child on the face of this earth, all 6.6 billion of us, 2000 cal or ies every single day, provided all of it goes directly to feeding humans, no intermediary livestock, and alas, no cat food or dog food. Or saving for a rainy day, or prolonged drought, as the case may be.

This left enough extra corn to make ~30 billion gallons of ethanol, which would provide us, just us here in the US, with about 20% of our gasoline use, assuming a 1:1 substitution of ethanol for gasoline.

In case you're curious, that 30 billion gallons of ethanol would have provided ~120 days food for
the entire world.

dent corn, aka field corn

5 comments:

Anonymous said...: Hi Hipparchia,

Curiously, I was just reading up on Ethanol production because of a report that the new Rudd Gov will reverse a stupid ban put in place by the Bushloving troll Howard on sugar cane growers here to produce ethanol (which only benefits the USA since using corn is more costly and far less efficient than using sugar cane). Brazil has been producing ethanol from sugar cane since the 30's, and have proven how efficient it can be. To quote:

In 2004, Isaias de Carvalho Macedo at the University of Campinas did a study for the state of São Paulo that considered energy inputs such as fertilizer manufacture and agricultural machinery in the sugar-cane industry1. He and his colleagues estimate that the whole shebang costs about 250,000 kilojoules per tonne of cane. That tonne of cane in turn yields about 2 million kilojoules in ethanol and surplus electricity made by burning bagasse. That's an eight-fold return.

This is a lot better than ethanol-makers in the United States manage, and the reason is clear to anyone who's ever strolled through a cane field chewing on a bit of the stuff; cane is a far more prolific plant than corn (maize), from which the United States makes almost all its ethanol, and it puts a great deal of its — or rather the Sun's — energy into making sugar.

What's more, sugar cane needs less by way of inputs, and in the parts of Brazil where most of it is grown at the moment it needs no irrigation. It needs only to be ploughed up and replanted every five years; between times it can be cropped repeatedly and will simply grow back, although the yields drop a bit with each harvest. For all these reasons, sugar-cane ethanol is also currently the cheapest ethanol to produce in the world. A litre costs about 25 cents to make. The commodity price for anhydrous ethanol (the kind mixed into gasohol) is about 27 cents.

Because of this a lot of money is pouring into the centre-south region of Brazil, where the sugar cane grows best.

Report is here:
http://www.nature.com/nature/journal/v444/n7120/full/444670a.html
Now, for some very strange reason, a 2006 US Economics report on using Sugar cane instead of corn said that it would cost more than twice as much! The report (which I am copying this from, I only have a PDF copy of it) states:

Cost of converting corn using a dry milling process into ethanol: $1.05 / gal

Cost of converting sugar cane into ethanol: $2.40 / gal

However, a Brazilian report from 2006 shows that converting sugar cane to ethanol in Brazil costs $0.81 / gal!

Ether the USA is woefully inefficient at it, or someone is lying. Probably both. :); Thursday, April 24, 2008 2:45:00 AM
hipparchia said...: liar, liar, rain forest on fire! or so they say... that by growing all those beets in the south of brazil, they're now cutting down the rain forests in the north to grow soybeans, primarily for export to rich countries for cattle feed.

sugar cane is a bit of a problem here in florida. it grows where we're trying to restore the everglades, and the growers use [and abuse egregiously] illegal immigrant labor, keeping them as actual slaves in some cases.

is this the pdf you mentioned?

thanks for the references. we clearly need to start coming up with alternatives to oil for a lot of things we use, not just fuel.; Thursday, April 24, 2008 10:05:00 PM
Anonymous said...: The quickest way out is conservation while a new source of energy is developed. Truckers are already backing off on speed to save fuel, and the Belgium national airline is about to follow suit, as it has found that back off on the throttles can save it a lot of money in reduced costs.

Even at this stage of development, solar can generate a lot of energy, and there are better arrays coming on line every year.

Ethanol is not an answer, it is an excuse.; Friday, April 25, 2008 10:26:00 AM
Anonymous said...: Ethanol is not an answer, it is an excuse.

Yes, and... no, Bryan. :) I understand what you are saying though. Ethanol is simply short-term means to ease the energy crisis. It's not a long-term solution by any means, that's true. Sadly however, in the USA it became simple a political tool. It's intended more to prop up ailing corn growers (and allied industries) than really providing any short-term energy relief. Even here, it's more about helping out the sugar cane growers in Qld. than any real energy gains, though at least they are being kinda honest about that! ;) LOL

I have an installer/plumber at my house right now installing a Solar hot water system. It has a gas hot water booster, but talking to people in our area that have had this system installed for a few years (or longer in one case), they say the gas is only used for up to approximately 20% of the year. Eventually, we plan to have a solar energy system installed also. The hot water system is costing us about $1,100 because of State and Feg gov rebates. Considering the gas hot water system was costing us about $25/Mth, and was about 12yo and needed replacing (leaky & inefficient), it's a good investment. The solar energy system we are considering is more expensive, but again we have good Gov rebates, and in Vic, we can sell the excess back to the primary grid on a 1:1 cost basis, and it looks like (considering our current usage) we should be able to sell 20% or more per year. Again, a good investment. The energy companies are publicly all for it of course, but I know they are lobbying hard in the background to have that 1:1 reduced in their favor so they can make a bigger profit off us. Thankfully, the new Labor Gov is having none of that and in fact may force them to reduce prices to households that convert to Solar when they need power from the grid. :) The energy companies are NOT pleased at all! So we are all for it! Anything that makes those greedy bastards upset is a good thing IMHO! LOL

Here in Victoria, especially rural areas, we are building some big wind farms. One was recently finished with 16 huge towers, and will provide power to several large towns and farms in the area for 80% or more of the year. It took almost 2 years to do a complete survey and model of the entire area to find the best place to erect the towers. It's a very complex system.

So, true, ethanol is not a good solution, and is not a viable long-term solution, but it can help in the short-medium term, especially in those parts of the World where cane can easily be grown and the land is currently being wasted. There is no need to destroy rain forests to do it! But Brazil wants to increase their GDP and lower their debts, and they see ethanol as the way to do it. Until someone comes up with a much better way for them to do it, nothing will change.

Same old, same old...; Friday, April 25, 2008 6:07:00 PM
Anonymous said...: One of my clients in the 1980s was involved in a proposal for wind power for Tasmania. They owned wind farms in California and were making money. I was crunching the raw data from some test towers, and they looked good for production. Don't know if the deal was ever closed because my client was bought out, and I didn't work with the new owners.

Ethanol from sugar cane might make sense, but not from corn. Making alcohol from corn has a long history in the American South, and it just isn't an efficient process.

We already waste corn producing High Fructose Corn Syrup as an industrial sweetener, so we don't need to waste any more on ethanol. It's a welfare program.

We were on the right track with the Carter policy, but Reagan trashed the entire effort.

[Insert bad joke about Republican Presidents all being Pharaohs because they are "kings of denial".]; Friday, April 25, 2008 6:30:00 PM