I am not anti bio fuel. Ethanol has a part to play. It is useful to meet requirements for oxygenated fuels for instance. It is useful as a boutique fuel for special applications. Here is the problem:
Earth has a surface area of 196,940,400 square miles, slightly less than a perfect ball with a diameter of 7913.5 miles (which is the mean diameter of the Earth).
The surface area of the seven continents and all the islands of the world is about 57 million miles, while the total area of the six habitable continents (Antarctica excluded) is around 52 million square miles.
Including Antarctica , over one fifth of the globe's land mass is under water (oceans, lakes, rivers, etc.) or ice. This leaves about 45 million square miles of exposed land.
The human population on earth has crossed six billion. If we distribute all the exposed land evenly among all mankind, 133 people would have to share one square mile. What that means is that every single person on Earth, man woman and child would have close to five acres of land for his or her use. More precisely, each person would get 209,000 square feet of land, or a square plot of land 457 feet on each side.
Not all this land can be used beneficially however. A significant portion of the Earth's exposed land is unhabitable or cannot be used for any agricultural purpose. Large portions lie in the far north. Large portions are extremely arid. Large portions are very mountainous. In sum, only about one fourth of all the land on earth, or somewhat more than 12 million square miles, is arable.
Today, over half of the arable land in the world is in fact not under cultivation. Bringing the unused land into service in many cases would require huge investments of money and effort, and would do considerable damage to the environment. For example, only about 28% of the arable land on the African continent is used for growing crops. Immense tracts of forests or jungles would have to be cleared to bring the rest of the arable land on that continent to productive use.
Thus, only about one eighth of each imaginary plot of land distributed to each person is land which is under cultivation. In effect, each person has a piece of land about 26,000 square feet (a square 161 feet on each side or just a bit more than ½ an acre) at his or her disposal on which to grow all that he or she needs. Now unless the world population starts to decrease, which is a trend I have failed to perceive yet, that half acre is going to keep getting smaller and smaller. Even if we start trying to put more land in production we will have to fight the earth muffins hammer and tongs, it will be expensive and will still, ultimately, not be enough to sustain the world population at some point.
I can remember the apocoylaptic screeds of the 60's and 70's such as The Population Bomb by Paul Erlich. We were supposed to be suffering worldwide famines by the 80s. We managed to forestall the gloomy outcomes predicted in these books through production agriculture but the issues raised in them are still valid.
Now ethanol can be produced at a rate of about 2.8 gallons per bushel. In the part of the world that I work in we are getting about 200 bushels of corn per acre so you can use your personal half acre to produce about 280 gallons of ethanol. Hey that doesn't sound bad...but wait...we had inputs which we have to subtract to figure out how much energy we are producing. We had to fertilize, run the machinery and, in some cases, irrigate. Then we had to transport the corn to the ethanol plant and process the ethanol. So what do we gain? Well a Berkeley study of three years ago says we are actually losing energy. Of course they were Berkeley professors and took the position that you really had to add the energy it took to mine the ore and smelt the metal that made the tractor. That doesn't seem fair to me so we can look at the Corn Grower's Association estimates of a net energy gain of around 20%. Using this more optimistic number we have a net energy gain of a mere 56 gallons of ethanol for your half acre. Since ethanol has about 2/3 the energy of gasoline that equates to about 37 gallons of gas.
Now you need to use your half acre to produce everything you are going to eat for the year as well as much of what you wear. So you can use your half acre to produce about 19 ounces of ethanol a day. That's not terrible news and equates to about 47 ounces of 80 proof. You can stay good and drunk but eventually you are going to want a bowl of corn flakes and a new pair of socks.
If ethanol is going to be produced on cropland, there is not enough in the world to make ethanol a viable energy alternative in any meaningful way, two or three percentage points of energy consumption maybe.
The inevitable corollary to this is that the more land that is diverted to energy production the more expensive commodities produced on the remaining land become. We are already seeing this in the case of corn which is now trading at around 5 dollars a bushel after hovering around 2 dollars a bushel from 1973 until about two years ago. Of course the market is being distorted by the massive ethanol subsidies and some people are already wondering if we are seeing a commodities "bubble". A commodities bubble preceeded the Great Depression by the way. Just sayin.
