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.”