Agriculture as provider of both food and fuel

Posted on May 19, 2010


(Swedish in another blog)

The road from project idea to scientific publication is normally a process that takes at least one year and often longer. In the spring of 2008 food prices rose markedly around the world. Production of ethanol for vehicle fuel was pointed out as one of the causes. My colleague Simon Snowden from Liverpool Management School had just shown that 60% of the price of milk in the UK was directly coupled to the price of oil. We had begun to discuss if it really was ethanol production that had caused the food price rises or whether it could simply be the price of oil instead.

Here are some articles that show just how inflamed the issue was in the spring of 2008. First CNN and ”Riots, instability spread as food prices skyrocket”, and here is another article on the subject: Why Are Global Food Prices Soaring? Let me conclude with this article from BBC’s home page: Bioenergy: Fuelling the food crisis?

We looked for someone who wanted to do a Master thesis on the subject at the same time as we made sure we had access to expert advice in the person of Professor Lars Ohlander at SLU [Swedish University of Agricultural Sciences]. In June 2008 Kersti Johansson and Karin Liljequist began their thesis work “Agriculture as provider of both food and fuel” and it became a “mammoth” project.

Our starting point was that food is energy and that it requires energy to produce food. The energy unit that one normally uses when discussing food is the calorie. According to Swedish authorities we should consume an average of 2500 kilocalories per person per day. If you are engaged in physical work then you need more calories than if you are sitting in an office in front of a computer. The standard unit for energy is the joule (J) but other units that are used are the calorie (cal), voltamperesecond (VAs), watthour (Wh) and electronvolt (eV). In the oil industry they use the unit “oil equivalents” that is the amount of energy in a barrel of oil. The Energy Authority gives Sweden’s energy use in units of TWh, terrawatthours.

We collected the data in this way: “Statistics on agricultural production were taken from the database of the Food and Agriculture Organization of the United Nations (FAO). The data used refer to the world production in year 2006 and includes 129 different crops”.

What we calculated: “The constructed database includes data on agricultural production for every individual country, making it is possible to calculate the energy content of crops and residues for any region. We chose to present results for both the world and the 27 member states of the European Union, hereafter referred to as EU27, since it plans to significantly increase the amount of biofuel in the transport sector within the union”.

In May 2009 Kersti and Karin had finished their thesis work (read the master thesis) and we decided to take it further and to write a paper for publication. It was necessary to condense a very detailed piece of work down to the right length for a publication. In October 2009 we were able to submit the paper to the journal Ambio. Then followed the peer review process and a few small changes had to be made before it was accepted for publication and, finally, published online on 16 April 2010.

In the past two years we have had 15 articles that have gone through a similar process and we have a number that are in various phases of the process described above.

When the study was conducted there were 6.7 billion people on Earth and that means that we then needed to eat food with a total energy content of 7100 TWh per year – or, if we express it in oil-based units it is 12 milliion barrels oil equivalents per day. Let’s read the abstract for the article:

Abstract: A database of global agricultural primary production has been constructed and used to estimate its energy content. The portion of crops available for food and biofuel after postharvest losses was evaluated. The basic conditions for agriculture and plant growth were studied, to ensure sustainable scenarios. The net energy contents for the world and EU27 was found to be 7200-9300 and 430 TWh respectively, to be compared with food requirements of 7100 and 530 TWh. Clearly, very little, or nothing, remains for biofuel from agricultural primary crops. However, by using residues and bioorganic waste, it was found that biofuel production could theoretically replace one fourth of the global consumption of fossil fuels for transport. The expansion potential for global agriculture is limited by availability of land, water and energy. A future decrease in supply of fossil energy and ongoing land degradation will thus cause difficulties for increased biofuel production from agriculture.

Ambio is the journal of the Royal Swedish Academy of Sciences. It is published by Springer. Here is the link to the journal and here you can read our copy of the article.

At the moment the world produces sufficient food for its human population but we know that much food is wasted. How much is difficult to calculate. As well, the distribution of food in the world is not just.

We have also tried to estimate the volume of byproducts from food production and it is, not completely unexpectedly, nearly as much as primary food production itself. From the study I think that it can be seen quite clearly that we should not make biofuel from food. Further, we show that there is a great potential for biogas production from agricultural byproducts and those byproducts already exist. There must be a global effort to institute this and, purely theoretically, we can replace 25% of today’s transport fuel with biogas.

In contrast, there is nothing that indicates that it was ethanol production that caused the food price rises. Rather, it was the price of oil that drove up the price of food. Ethanol from maize in the USA can have had local significance, but ethanol from sugar cane is, instead, a byproduct of the production of sugar.

Detailed studies in the USA show that 1 calorie of prepared food on the table requires, commercially, the equivalent of 7.4 calories to put it there. A global average is 5 calories per calorie of food on the table. Most of this is energy is from fossil fuels. If we take our food requirement of 12 million barrels of oil per day and multiply it by a factor of 5 we get 60 million barrels of oil equivalents per day which is 30% of all fossil fuel use. Those that call for zero carbon dioxide emissions by 2050 must first explain how an estimated 9 billion people will be fed.

You who blog and become instant experts and dismiss what we researchers say without regard to our research results should understand that a research report takes time to write. Finally, I would like to thank above all others Kersti and Karin. I am enormously proud that we have such fantastic students at Uppsala University.

Posted in: Dagsaktuellt