24 Oct 2009

Biofuel Awareness: How Green is It?

Biofuels are good, as people say. But why? Being an undergrad, I felt an urge to understand. And in the end, I found biofuels are not necessarily good. First, we have to understand the reason of biofuel production. It seems that fossil fuel is the main factor. Not only that we're running out of fossil fuels, they also release greenhouse gases (GHG; in this short essay, CO2 will be the primary GHG discussed. ) that is claimed to be the main contributors of global warming. Therefore, we need something to substitute fossil fuels in order to fill our hunger for energy and mitigate the negative impact of our fuel production. Here comes the suggestion, why don't we use plants or animal waste as fuel feedstock? Biofuel feedstock, which is the material for production, can be anything that is derived from the biosphere and can be oxidized to produce energy. However, if its net energy per biomass (GJ/t) produced is not able to compete with the net energy produced by fossil fuel, we discard this feedstock and find another one. In addition, if carbon output is more than carbon input during production, we also discard the feedstock.These two main considerations, net energy value and net CO2 emission, generally judge the "green" quality of a biofuel. For example, the popular corn-based and soybean-based biofuels are currently hot in USA. However, these biofuel that are derived from food crops (I am sure you eat a lot of corns and soybeans annually) have various negative impacts to the environment, such as (1) high GHG emission due to excessive use of nitrogenous fertilizers and use of fossil fuel during production (transportation and power generation for biorefinaries), (2) pollutions caused by pesticides, and (3) competition with food market. In short, these kind of biofuels will not be "green" enough before their negative impacts are outweighed by advantanges. In conclusion, all you have to know (as part of the public) is:
  1. We must bear in mind that biofuels also have negative impacts on Earth;
  2. We need to find solutions for these negative consequences to enhance the "green" value of biofuels;
  3. We are not eliminating all negative impacts of biofuels, instead we are mitigating them and trying to outweigh them with the benifits of biofuels;
  4. Biofuels cannot stand alone to sustain our energy needs, i.e. a cocktail of alternative renewable energy sources (e.g. solar+nulear+wind+biomass) is more feasible.
"Alright lads, tuck this tube into your backsides when you wanna fart. I need some methane for biofuel."
p/s: Thank you Prof. Gasparon for the idea of methanol from sheep.


  1. Oh, I love the picture, especially the expression of the lambs, nice drawing.

    But how nitrogenous fertilizers generates more GHG? Industrial method of creating nitrogenous fertilizers doesn't seem to do much...

    Also,It does generate extra pressure for the food demand, but it lessen the demand for energy. It does balance out in some way.

    In the case of South America Country, the bloom of biofuels pushed their economics. So, can't they feed themselves with the extra money? If biofuels is successful, the money will flows towards agriculture country, which consist of mostly poor country.

    It all comes down to priorities and
    scarceness of the products, and they balanced out in some way. (water vs diamond : economics). If food is scarce, biofuels will probably be put off. No one want extra money if they can't feed themselves.

  2. Thanks guy.

    Fertilizers usually contribute to increase in GHG by increasing the amount of NxO products. Other than CO2 and CH4, NxO is also part of the greenhouse gases. Other than greenhouse effect, Nitrogenous fertilizers also induce eutrophication in lakes and oceans, e.g. the algae bloom in Mexico Gulf.

    Indeed, in some places biofuels do benefit social and people. Brazil, where sugarcane is widely used as biofuel feedstock, is an example for South America. However, other countries that are less advance in biofuel industry than Brazil is suffering from food vs. fuel dilemma, such as Egypt. As more and more food crops are turned into fuel production, food prize increases.

    Even though people can cope with the two-way application of food crops, I still suggest us to search for a better feedstock. I am interested in lignocellulosic biomass and waste oil (e.g. cooking oil and animal fats), but I won't discuss about them here because they're complicated. Try some online articles, these feedstock are getting our attention and are being focused now. It's good to hear some comments from you. Cheers.

  3. The issue of biofuels competing with the food market keeps popping up in my Economics classes. It's been blamed for causing food price hikes.

    I think the ideal biofuel would be biological waste. It's not like you need it for anything else, so economically speaking it doesn't affect the food market.

    While we're on these Green topics... incidentally, I read a recent Newsweek article that argues that Carbon Trading is useless.