Developments in Biofuels; Implications for Livestock Production

As the manufacture of biofuels grows, questions are being asked as to whether such a strategy can be supported without putting unacceptable pressure on the food supply chain, writes John Pinkeye, Ensus Biofuels, in the proceedings from the 42nd University of Nottingham Feed Conference.

This paper critically assesses the arguments and looks in particular at the impact of biorefining wheat in Europe to both provide a new source of protein concentrate for the animal feed sector, and support the growth of Bioethanol as a substitute for gasoline/petrol.

In order to respond to the challenge of global warming, transport fuels are a priority for action; they are the source of over 18per cent of Greenhouse Gas (GHG) emissions in the EU and are notable as the only significant source of GHG which are increasing. Whilst more efficient cars and new technologies will inevitably contribute to meeting this challenge, the use of biofuels is an essential element of the strategy to decarbonise transport fuels. Biofuels vary in their contribution to saving carbon. Manufactured in the right way and using the right feedstock, biofuels can reduce GHG by at least 50per cent compared to fossil fuels Refs 2 and 3.

Conventionally, land has been used to meet the world's food requirements, while other sources such as oil, coal and gas have been used to meet energy and transport fuel requirements. In other words, today's sun has been used to feed the world and yesterday's sun (over millions of years) has been used to meet the world's energy and fuel needs. The challenge now is to use land and today's sun to meet not only the world's food needs but also its requirements for energy and transport fuel requirements. The critical question is whether this can be done without putting undue pressure on the planet's food supply chain and land use.

Bioethanol is manufactured through the fermentation of sugars. Today this is done by accessing sugars directly (sugar cane and beet) or by breaking down the starch in grains such as wheat to sugar. Biorefineries for the manufacture of bioethanol from cereals also produce a co-product of protein rich animal feed (DDGS) as well as carbon dioxide. Previous studies that have compared the biofuel yields from alternative crops have almost entirely ignored the credit for high protein co-products, such as DDGS from grain crops.

In meeting our food requirements, growing protein in sufficient quantities and concentrations is critical. Although cereal crops such as wheat and maize are very efficient at converting the sun's energy, the concentration of protein is too low for animal feed. Soy meal is widely used as a supplement to raise protein levels and Europe today imports about 35 million tonnes of soy meal to use as an animal feed supplement.

However soy makes inefficient use of land and of the sun's energy producing only 2.5 tes/ha, compared to a yield of 7.7 tes/ha for wheat in NW Europe. When cereals are biorefined to make bioethanol, the protein in the co-product DDGS is at a much higher concentration than in the original cereal and can replace soy meal. This means that cereals produce high protein feedstocks as well as low carbon biofuel, thus creating the opportunity for much more effective use of land.

Thus at current yields, the use of cereals to produce bioethanol could enable more effective use of the land by growing a greater proportion of crops which are more efficient at converting the sun's energy to food and biofuel products. The use of bioethanol DDGS to replace soy meal could therefore enable large scale EU production of biofuel from wheat and maize of 35mt/yr with only a small net increase in the global arable land area. With continued increases in cereal yields, the bioethanol can be obtained with no increase or even a decrease in global cropland area.

For example with sustainable higher cereals yields and an increased land use of 4 million ha, the supply of biofuel cereals in the EU could be increased by about 110 million tonnes per year (mtes/yr) by 2020. This would enable production of about 44 mtes/yr of bioethanol in the EU, which could replace more than 8per cent of the EU road transport fuels consumption. The increased protein production from the DDGS would reduce EU import of soy meal by 18 mtes/yr and would reduce the area required for growing soy in South America by 6 million ha. There would result in a net decrease in land area of 1.5 million ha. This is not the whole story. The above analysis only considers wheat grain.

When growing wheat a similar amount of straw and stalks are also produced, ca 8 tonnes/hectare, of which half is harvested and is available for use to generate energy, either for power generation, or biofuel. In fact when this is taken into account wheat has the potential to be a very effective way of meeting the world's food, fuel and energy requirements and is more effective than ligno-cellulosic energy crops on arable land.

In summary therefore, this paper shows that biorefining wheat to biofuels is a much more efficient process than has been generally recognised, which uses little if any net new land, and which, far from competing with food, actually makes a very valuable contribution to the food industry by virtue of providing an alternative source of feed protein concentrate.

Not only does this substantially help the food industry cope with future growth, it also makes a massive environmental contribution by reducing the pressure on tropical land, some of which is heavily associated with continued deforestation. The paper also shows that Europe's capacity to source biofuels from its indigenous cereal production is substantial, with the ability to meet the targets currently being proposed in the European Renewable Energy Directive draft legislation, with minimal if any need for imports or development of costly so called second generation ligno-cellulosic technology.

September 2008