We’re hearing more and more about biofuels because they’re an alternative fuel (i.e. “good”), because they don’t increase carbon dioxide in the air (“good”), because they can be produced any time any where (“good”), they can be used in current cars (best of all), and are generally the solution to a zillion looming problems.
If it sounds too good to be true, that’s because it is.
The first problem with biofuels is figuring out what people are talking about. Ethanol from corn? Crop waste used in power plant cogeneration? Methane gas from landfills? Or composting toilets? Alcohol from cellulose? Fryer oil biodiesel?
The second problem is that “bio” doesn’t equal “good,” no matter how green it sounds. Some of these technologies are shaping up to be worse than our current oil-based one. The worst problems are at the production end, not during consumption, which makes it much easier to bamboozle rich-country consumers into thinking they’re helping the planet. We need to be aware of what different biofuels really mean before rushing into alternative energy “solutions” that are anything but.
All biofuels have some similarities. They can fit into the existing fuel infrastructure for liquid or gas delivery. This is a big deal, since any short term application of alternative energy is easier if it uses existing facilties. So that really is good. However, they all have to be burned to release energy, so they pollute the air, and they lock us into the same oily, greasy, smelly crud as petroleum (for lubricant, if nothing else). Sure, the details are different, but these are not eat-your-dinner-off-them technologies like electric cars (at the point of use). Chalk one up in the “ugly” and “bad” columns.
One big selling point for biofuels is that they don’t contribute to global warming. It’s true that the carbon they release is what they took from the atmosphere not long before. They’re not releasing new carbon which was buried under ground and doing nobody any harm down there. In other words, they’re “carbon neutral.” They don’t hurt the situation, but they don’t help it either. They may or may not, depending on the fuel, contribute less than petroleum products, but that’s not the point I’m making. The carbon they fix is the same carbon they release when burned.
There are also plenty of differences among biofuels. Alcohols, like ethanol or methanol, are quite clean-burning, as are gases, like methane. (Natural gas is mostly methane, but it’s fossil methane, so it releases carbon into the air instead of keeping it underground.) Even though alcohol doesn’t pollute as much as gas (i. e. petrol), if every car on the road used it, a place like Los Angeles would still have plenty of photochemical smog just from the inevitable incomplete combustion products.
Biodiesel is not as bad as “real” diesel in some ways, but it tends to have higher nitrous oxide emissions. So much so that it can have trouble passing California smog checks, for instance. (People are trying to find fixes for the NO issue.)
Then there’s the really smoky stuff, like burning crop wastes in a power plant for co-generation. That sounds grim, but it’s a point source, and an industrial one at that. That means all those emissions can be scrubbed down to almost nothing. They may not be, but they can be.
The entire energy cycle has to be considered, right down to what happens to any waste generated in production or residue left after burning. A dirty point source that can be controlled may be a better choice than a rather clean but diffuse source that can’t be. That has direct implications for the whole electric versus biofuels argument. All that nice clean electricity has to come from a dirty old power plant. But if the dirty plant has excellent scrubbers, that may be a cleaner solution than even the best methane-burning cars.
All that, though, is looking at it from the point of view of the consumer. The production end turns out to have a huge impact of its own. We need to pay way more attention to that. The situation can be so bad that some of the supposedly green technology turns out to be blacker than coal.
The first point is whether the raw material is already lying around, or whether it has to be produced. Is it waste? Or is grown, processed, and shipped? There’s a huge difference.
When biofuels first started, it was all about using waste: burning garbage for cogeneration, capturing methane from landfills or composting toilets, and that kind of thing. This is where biofuels got their environmental street cred. The raw material was already there. Money was going to be spent getting rid of it. It caused pollution. However, using it as a fuel reduced the pollution (usually!), and produced value instead of spending it.
All that is wonderful, and all that is definitely the way to go. Needless to say, that’s not the way people are going.
Producing biofuel from anything that isn’t waste is where the really bad and ugly parts come in. Alternative energy use has barely begun to take off, and already, the powers-that-be are turning this into another tale of sick-making exploitation and destruction. There are some horrifying trends taking shape. We have to do everything we can to stop them before they go any further. (The points below come from: UN Energy, Sustainable Bioenergy Report (pdf) , BBC report of the charity Grain , and e. g. other  BBC reports )
Now, if there was a way to make ethanol from waste, the production-side problems could go away. God knows there’s enough crop waste polluting the planet. The problem (there’s always a problem) is that crop waste is basically cellulose. Wood, straw, paper, cloth, are all mainly cellulose, and none of them rot easily. That’s because there’s almost nothing that can break cellulose down (which is why plants use it for their cell walls, of course).
Using yeasts to ferment grain and produce ethanol has been thoroughly worked out over the millenia. But we don’t have anything equivalent for the digestion of cellulose. The bacteria and fungi that can do it are tricky to grow in vats, unlike yeast. This is a problem that can be solved with enough bioengineering, but we’re not there yet in terms of mass production and cheapness. (See, eg here  for a bit more on cellulases, the enzymes that digest cellulose.)
Currently, the largest producers of cellulosic ethanol  use chemical or heat treatment to break down the cellulose into its component sugars which can then be fermented the usual way. Needless to say, all that pre-treatment uses a good bit of energy, as well as being quite polluting in some cases, and turns this whole potentially green technology rather turd-colored.
There are three take home messages. One is that if people want to run their cars on ethanol, the best choice is to pour resources into bioengineering a good cellulose digesting microorganism. If we can’t get some fungus to do it for us, it’s not worth doing. Two is that biofuels from waste are okay in industry, such as power plants with excellent scrubbers, but they’re not all that ready for prime time as a transportation fuel. Even if they do use existing infrastructure. And three is that biofuel made notfrom waste is blacker than the Darth Cheney’s heart.
The push for biofuels in rich countries is largely based on the desire to use existing infrastructure. (In poor countries, it may simply be the only option.) But what we’re trying to achieve is sustainable energy, not infrastructure. If the infrastructure actually interferes with the real goal, maybe it’s time to rethink the infrastructure. If it’s part of the problem, maybe it’s time to give up on dead-ends and spend what it takes to go electric. Or maybe there’s some other, more elegant solution.
What’s your take on it?