Biodiesel Featured Articles
Biofuels and Agriculture
Second generation biofuels produced from lignocellulosic feedstocks have major implications for agriculture and food security, writes TheBioenergySite Senior Editor, Chris Harris.
At present for first generation biofuels feedstocks include crops such as corn, sugar cane, rapeseed and soybean as well as traditional biomass including wood, charcoal and animal dung.
However, the UN Food and Agriculture Organisation report The State of Food and Agriculture 2008, questions the overall value of using the traditional food crops for the production of liquid biofuels and the sustainability of the current feedstocks used in the production of bioenergy.
The report says that bioenergy, through the use of biomass largely for cooking and heating is already the most dominant energy source for most of the world's population, who live in extreme poverty.
Source - IEA, 2007.
But it says that the goal has moved as more sophisticated technologies allow the conversion of feedstocks into other solid, liquid and gaseous biofuels.
The strongest growth in the new biofuels has been in liquid biofuels for transport, which are produced from agricultural and food commodities.
"There are many supply sources of biomass for energy purposes, scattered across large and diverse geographical areas," the FAO report says.
"Even today most energy derived from biomass used as fuel originates from by-products or co-products of food, fodder and fibre production."
It adds: "In terms of bioenergy, however, the big growth area in recent years has been in the production of liquid biofuels for transport using agricultural crops as feedstocks.
"The bulk of this has taken the form of ethanol, based on either sugar crops or starchy crops or biodiesel based on oil crops."
Most global ethanol production is derived from sugar cane or maize; in Brazil, the bulk of ethanol is produced from sugar cane and in the United States of America from maize. Other significant crops include cassava, rice, sugar beet and wheat.
For biodiesel, the most popular feedstocks are rapeseed in the EU, soybean in the United States of America and Brazil, and palm, coconut and castor oils in tropical and subtropical countries, with a growing interest in jatropha.
The FAO says that energy policies in most developed and some developing countries are changing the shape of agriculture around the world.
It says that while bioenergy offers a new source of demand for farmers' products creating new income and employment it also creates increased competition for natural resources such as land and water.
"Competition for land becomes an issue especially when some of the crops (e.g. maize, oil palm and soybean) that are currently cultivated for food and feed are redirected towards the production of biofuels, or when food-oriented agricultural land is converted to biofuel production," the report says.
At present ethanol represents 85 per cent of the world's production of liquid biofuel, with Brazil and the USA being the main producers. These two countries alone account for 90 per cent of global production. Other countries such as Canada, China, France and Germany in the EU and India produce most of the remainder.
Biodiesel production is based largely in the EU, which makes about 60 per cent of the total world production.
While energy security has been one of the main drivers for production of biofuels and the concern over access to fossil fuels, the reduction in greenhouse gases has also been cited as a major reason for their production.
"Just as different crops have different yields in terms of biofuel per hectare, wide variations also occur in terms of energy balance and greenhouse gas emission reductions across feedstocks, locations and technologies," the FAO says.
The FAO has also measured the amount of energy it takes to produce new biofuels, giving each feedstock a "fossil energy balance".
The report says that a fossil energy balance of one means that an equal amount of energy has been used to make the fuel as it gives. The higher the balance number, the more energy is received from the fuel and the less it takes to produce.
The FAO shows that there is a wide variation in the estimated fossil energy balances across the different feedstocks and fuels. For example, biodiesel from rapes seed or soybean has a balance of one to four, while the estimated balance for biodiesel from palm oil is around nine.
For ethanol the balances ranged from less than two for maize to between two and eight for sugar cane.
The range for cellulosic feedstocks is even wider than that for sugar cane, which the FAO says represents the variety of raw material feedstock, the different production methods and uncertainty surrounding the technology at present.
Cellulosic biomass is the most abundant biological material on earth, and the FAO says that the successful development of commercially viable second-generation cellulose-based biofuels could significantly expand the amount and variety of feedstocks that can be used.
Cellulosic wastes, including agricultural waste products such as straw, stalks, leaves and forestry, wastes generated from processing such as nut shells, sugarcane bagasse, sawdust and organic parts of municipal waste, could all be potential sources.
"Dedicated cellulosic energy crops hold promise as a source of feedstock for second generation technologies" says the FAO report, which adds that second generation biofuels could also have an impact on greenhouse gas emissions.
The FAO says that second generation biofuels could present a completely different picture in terms of their impact on agriculture and food security, because a much wider range of feedstocks can be used than those crops used in first generation fuels.
They will also have an effect on land use and the environment and through new technology can give higher yields than traditional crops.
The FAO warns that if the total crop production area in the world was devoted to ethanol production, it would only account for 57 per cent of total petrol consumption. IT adds that is just 25 per cent of the crop area is devoted to ethanol production, this would account for 14 per cent of the petrol consumed.
It adds that second generation biofuels from cellulosic feedstocks such as wood, tall grasses and forestry and crop residues, would increase the amount of biofuel potentially produced per acre and at the same time it would increase the greenhouse gas and fossil fuel balance.
However the FAO also warns that it is not yet known when the technology will be in place to make this a viable proposition.
