Disadvantages of Biofuels

Biofuels were once touted as the saviors of the economy and the answers to our ever growing energy needs. As it turns out, they aren't quite the silver bullet they were claimed to be. Though biofuels have a number of advantages over fossil fuels, their integration into the fuel supply chain has to be done with great care to ensure that their potential disadvantages are, if not eliminated, at least minimized.

At the current time, more "radical" alternative fuel technologies such as solar and wind have one major problem - portability. It is very difficult to transport large quantities of electricity without using heavy, relatively inefficient batteries. Biofuels, on the other hand, are fairly easy to transport, have decent energy densities, and can be used with only minor modifications to existing technology and infrastructure. With that in mind, it seems that biofuels will likely act as a stop gap or filler that helps us as we transition from fossil fuels to other technologies that aren't quite ready. We attempt to outline the disadvantages that should be considered when a biofuel is being implemented, not to discourage their use, but rather to encourage responsible use of this technology, which is likely to become our predominant source of energy as we transition over to cleaner alternatives in the more distant future. With that in mind, here are the disadvantages to be aware of.

Regional Suitability

Despite pushes for Jatropha, Camelina, and algae, it is more likely that biofuel feedstock will be grown on a regional basis. This is important for a number of reasons, chief among them being the fact that some crops just grow better in some locations and not so well in other. Things that will need to be taken into consideration are:

  • Water use - The less water a crop uses, the better as water is a very limited resource. This is particularly important in places that are more arid.
  • Invasiveness - A crop that kills native plants and which is difficult to control is not a good choice as it may threaten biodiversity and severely damage the surrounding ecosystem.
  • Fertilizer - Nutrients are needed for plants to grow. Some plants are more frugal with scarce resources than others.
  • Limitations - Some places just aren't going to be able to grow biofuel crops. Alaska, for instance, really isn't suited to the rapid growth needed to produce crops year after year for fuel supplies. Regions like this will have to import fuels, so energy independence still will not be possible for every location.

Food Security

Biofuel feedstock has to be grown and there is only so much suitable land in the world for growing plants. Very little, for instance, is going to grow in the Sahara Desert. The problem with growing crops for fuel is that they take up land that could be used for growing food. In a world with a population of around 7 billion and that is already short on food, there will necessarily be a tradeoff between food crop and biofuel feedstock. Every effort is made to grow feedstock that uses "none agricultural land." This means crops like corn and soybeans are out of the running.

Now, the impact on the food supply may not be quite as great as initially estimated for the simple reason that land classified as "agricultural," isn't necessarily being actively planted. This has occurred as advances in crop technology have led to the production of larger harvests on less land. Estimates in 2008 suggested that the following regions could grow biofuel on abandoned agricultural land.


Biofuel Production

(millions of tonnes/yr)


88 - 245


139 - 293


95 - 321


144 - 364

North America

211 - 697

South America

154 - 480

The problem is as difficult to ascertain as it is to solve. Some estimates suggest that if biofuel production doubles from its 2006 production, then by the year 2020 there will be an additional 90 million people at risk of hunger on top of those already at risk. This should indicate that even though farmland sits unused, that does not mean that there is abundant food across the planet. The truth may be closer to the fact that unused farmland is not profitable for food production, even though tens of millions of people are at risk of hunger right now. The vast majority of the increase in "at risk for hunger" individuals, if biofuel production increases, will occur in Eastern Asia, but there will still be 20 million people in "developed" countries who will be additionally put at risk. The major driver of this increase in hunger risk comes from increases in food prices that will result from the fact that agricultural land can "earn more" if it is planted with biofuels. That means farmers will demand higher prices for food to offset what they lose by not planting biofuel feedstock.

Land Use Changes

This one is little more difficult to understand, but you can think of it as akin to deforestation. If the land used to grow a biofuel feedstock has to be cleared of native vegetation, then ecological damage is done in three ways.

The first way damage is caused is by destroying local habitat. This necessarily destroys animal dwellings, microcosms (micro ecosystems), and reduces the overall health of a region's natural resources. The loss of plant life also means that the world loses valuable CO2 scrubbers. Even though the land is being replanted, a native forest is almost always better at removing CO2 from the atmosphere than a biofuel feedstock, in part because the CO2 remains trapped and is never released by burning as with fuel stock.

The second way that damage is done is in the carbon debt created. Energy is needed to deforest an area and prepare it for farming as well as to plant the crop. All of this leads to the production of greenhouse gases and puts the region at a net positive GHG production before a single biofuel is even produced. Then, energy must be invested into harvesting the replanting the crop the next time around. Estimates have shown that deforesting native land can actually produce a carbon debt that can take up to 500 years to repay. So, using native land for biofuels, even if no food is grown on it, puts us in the hole ecologically.

Finally, as if the two problems above where not enough, changing land to agricultural status almost always means fertilizers are going to be used. It only makes sense to use fertilizer if we want to get the most yield per area. The problem is runoff and other agricultural pollution, which rivals that of urban pollution in its impact on the local environment. Thus, creating more farmland is likely to damage waterways and require us to invest energy into treatment plants and other mitigation strategies. The net result is an even larger carbon debt.

As one can see, land use changes for biofuel production are a very, very bad way to go and should be avoided at all costs. The best solution is to use existing land, but that puts food supplies at risk. So the problem is very difficult to solve. Some people have proposed using algae, which grows in very inhospitable regions and has limited impact on land use. The problem with algae, however, is water use.

Monoculture, Genetic Engineering, and Biodiversity

It is easier to grow a large quantity of a single crop if it is all very uniform. This is referred to as monoculture and examples can be seen in the corn, soybean, and potato farming sectors. Potatoes in the U.S., for instance, are almost always Russet potatoes because that is what is in demand by large consumers like fast food chains. The problems with growing a single crop over large tracts of land are several-fold.

First, growing only one crop changes the environment in terms of the food available to pests. This is an evolutionary pressure that can lead to a number of problems. For instance, if a crop of potatoes is eaten by a certain pest that can only migrate a few hundred feet and the potato fields are separated by corn fields, then an outbreak in one potato field is not a problem because it won't spread. Without the corn fields, however, the pest is free to destroy an entire crop.

Now, for the second problem, we could treat the pests mentioned above with pesticide, but it is inevitable that a few of those pests will be resistant. After all, out of the hundreds of thousands or even millions of insects, bacteria, and fungi that can inhabit a single field of crops, at least a few are likely (by chance alone) to be resistant to the chemicals we use to kill them. After all, we can't spray too much as it would be damaging to human health. So the result is a pest that is resistant to pesticide. Now it is free to eat all the crop it wants and we are powerless to stop it.

The next problem comes when we turn to genetic engineering. We decide to modify the crop so that it is resistant to the pest without the need for pesticides. Great! The problem is, the same things happens because it is likely at least a few pests aren't affected by the modification or a new pest comes along and we are left, after a few years, with the same problem as when we began.

The point is, there are limits to how much of a single crop can be grown and there is little that technology can do about that. The key to healthy crops worldwide is biodiversity, which simply means having lots of different types of plants and animals around. That way, if the Russet potatoes suffer blight, we still have Yukon Gold or Red Thumb potatoes to turn to. This is especially important when dealing with food crops. Just ask the Irish and they'll tell you how much havoc a pest can wreak in a food supply built on a monoculture.

Global Warming

This probably goes without saying and won't be belabored here, but burning biofuels, which are most hydrogen and carbon, produce carbon dioxide, which contributes to global warming. So, even though biofuels may be able to help ease our energy needs, they won't solve all of our problems.

Now, it may be true that biofuels produce LESS GHG emissions than fossil fuels, but that can only serve to slow global warming and not to stop or reverse it. Thus, biofuels can only be substitutes for the short term as we invest in other technologies. The key to implementing them is to mitigate environmental impact by being mindful of the disadvantages we have discussed.