Earlier this month, in our post “Biofuel’s Potential,” we compared the best case biofuel yields today - about 10,000 barrels per square mile per year - to the best case biofuel yields in the future according to many biofuel experts - about 50,000 barrels per square mile per year. To summarize, the difference between 10,000 barrels per square mile per year and 50,000 barrels per square mile per year is the difference between a supplemental fuel of some economic value, and a scaleable, viable fuel alternative that could literally replace petroleum.
For some time we’ve been looking for a way to present quantitative cases using interactive spreadsheets, and a new company in Sweden, SpreadsheetConverter, has finally delivered something that we can work with. Unfortunately, their software won’t function in the WordPress environment, at least not yet. But if you click on “LAND FOR BIOFUEL CALCULATOR” you can do your own math. The cells highlighted in yellow are input cells - if you don’t like our assumptions, enter your own.
The interactive table we’ve constructed, “Land for Biofuel,” calculates how much land and water a typical American suburb requires, then calculates how much land and water would be required to supply that city with biofuel for 100% of the automobiles in the city. The default case is for a city with 100,000 people, using corn ethanol that requires irrigation. All of the values in the yellow highlighted cells are based on yield and consumption data we’ve checked, but the beauty of this table is you can enter your own assumptions if you don’t like ours.
To view the results, you need to click the curser on a highlighted cell, then move it away and click again. This is a workaround, but again, this is the best interactive online spreadsheet we’ve ever found.
And the results are interesting. In a city of 100,000 people, at a population density of 5,000 people per square mile (what used to be a high density suburb, but what the smart growth people now call eggregious sprawl - read “California Land Use Choices,” or “Critique of New Urbanism“), the city itself would consume 20 square miles. The land necessary to provide the inhabitants with 100% of their automotive fuel would consume an additional 190 square miles, a ratio of 9.5 to 1.0.
We have used 2,500 barrels per acre per square mile per year as our yield assumption, based on data we’ve compiled on current yields from corn ethanol (read “Is Biofuel Water Positive“). But if we were able to get the kinds of ethanol yields from corn in California that we get from sugar cane in Brazil, 10,000 barrels per square mile per year, then our sample city with a housing footprint of 20 miles would only require 48 square miles of biofuel cropland - a ratio of 2.4 to 1.0. And if the most optimistic claims of biofuel proponents are to be believed, eventually we will extract 50,000 barrels of ethanol per square mile per year from advanced biofuel crops, in which case our sample city with a housing footprint of 20 miles would only require 10 square miles of biofuel cropland - a ratio of 0.5 to 1.0. The water requirements of biofuel crops are also an issue, of course, and in semi-arid places like California this is not an afterthought - our calculator indicates it would take 5 times as much water to irrigate corn ethanol crops than to supply the households who would be consuming that ethanol.
Clearly if biofuel yields reach their claimed potential, biofuel can replace petroleum. But will they? And no discussion of biofuel from here should end without this cautionary refrain - carbon offset funds from Europe have subsidized biodiesel, creating a land rush to grow oil palms and other biodiesel crops, unleashing what is well on the way to being the most devastating rounds of tropical deforestation in the history of the world. Anyone who cares about wildlife, wilderness, or climate health, should be paying attention. Read “Reforesting vs. Biofuel.”
December 29th, 2007 at 10:42 am
Does corn fuel ethanol policy increase oil profit and increase oil use?
* Some folks think so
* Clean Air Performance Professionals
December 29th, 2007 at 12:44 pm
You need to look into the “Energy Return on Investment” (EROI) for biofuels - that is the ratio of total energy available for use divided by the total energy input. A ratio of less than 1.0 means the process consumes more energy than it provides. Corn ethanol has a EROI of 0.8 to 1.2, making it a non-viable business without government subsidies. The only thing that keeps it going is government subsidies and cheap petroleum based fuel. By contrast the EROI for oil, gas, and coal extraction is in the range of 20 to 100.
EROI is well documented. For more info, see theoildrum.com or energybulletin.net
December 29th, 2007 at 2:44 pm
Eroei is negative for all biofuels. You will not have a biofuel powered autotopia. Not going to happen. Why don’t the pseudo-greens quit being apologists and auto/tech worshippers and advocate the complete cessation of automobile use?
Technology is not the the solution. It is the problem.
For information about eroei for biofuel, go to:http://www.ce.berkeley.edu/faculty/faculty_pubs.php?name=Patzek
Because humans are incapable of holistic thinking except in the briefest of spontaneous moments or after years of training, I seriously doubt that we will start backing down the technological cul-de-sac we have so blindly driven into.
For a really eye-opening moment go to:
http://globalpublicmedia.com/dr_albert_bartlett_in_depth
After watching the films, you may have a better understanding of why the drive to tech our way out of our situation is fraught with perils.
December 29th, 2007 at 6:37 pm
[...] EcoWorld - The Global Environmental Community - Nature and Technology in Harmony In a city of 100,000 people, at a population density of 5,000 people per square mile (what used to be a high density suburb, but what the smart growth people now call eggregious sprawl - read “California Land Use Choices,” or “Critique of New Urbani (tags: biofuel) [...]
January 1st, 2008 at 7:17 am
EROI for sugarcane ethanol is between 8 and 10 to 1. That for cassava ethanol around 5 to 1. That for cellulosic biofuels is about 20 to 1. That for synthetic biofuels around 10 to 1. That for biogas based on sugarcane or sorghum is between 12 and 15 to 1.
Most advanced biofuels now have an EROI superior to most newly pumped up oil (e.g. in deep-sea fields, highly energy intensive).
With advances in microbiology, synthetic biology, biotechnology and bioconversion, the EROI will go up much further.
According to the IEA’s Bioenergy Task 40, the planet can sustain around 1400 Exajoules of bioenergy for exports (international trade) by 2050 under a high input, high tech scenario, WITHOUT deforestation, and WITH ensuring the food, fiber, fodder, and forest product needs of growing populations.
1400 EJ is around 7 times as much than all the oil consumed by the entire world.
In short, there is no debate about carrying capacity or about potential. The planet can produce more sustainable bioenergy than mankind will ever need.
January 16th, 2008 at 11:17 am
Jonas - first of all, thank you. Until I read your comment I had been confusing exajoules with petajoules. In any case, since 1.0 exajoules is roughly equivalent to .95 quadrillion BTUs, and since humanity currently requires about 500 “quad” BTUs per year (all energy sources, not just petroleum), then these 1,400 exajoules you reference indeed would constitute 3x total energy currently consumed worldwide, and probably 3x total petroleum currently consumed worldwide.
But where did you get your figures? To get to 1,400 exajoules, you would need 50,000 BBL per square mile, with 5 million square miles committed to biofuel crops. I agree the math works, but I’d like to see more evidence regarding yields of this magnitude.
July 21st, 2008 at 2:15 pm
pls send
September 28th, 2008 at 4:49 pm
Very cool, I build biodiesel processors which turn waste vegetable oil into biodiesel. It is really amazing how simple the process is, as well as saving the customer $2-3 per gallon at the pumps. Algae biodiesel looks even more promising. As the other poster said, we just need to keep moving in the right direction.