Fact is that not all biofuels are created equal. They can be produced from a wide range of crops and thus vary significantly in terms of characteristics and environmental impacts. This built-in ambiguity means that biofuels must be analyzed and judged independently. Just as there are different types of biofuels, there are different species of underlying feedstock for them. While Bio-ethanol is generally derived through fermentation from crops such as sugar cane, corn or wheat, Bio-diesel is generally derived through trans-esterification of vegetable oils from crops such as soybean, rapeseed, palm or jatropha.
Biofuels may make a difference in terms of achieving the different policy objectives pursued. However, not all biofuels perform equally well in terms of their impact on climate, energy security, and on ecosystems. Environmental and social impacts need to be assessed throughout the entire life-cycle. On one hand, most biofuels are attractive in that they may serve to replace imported oil and help diversify energy resources. However, some current (“first generation”) biofuels, such as ethanol from grains and biodiesel from oil seeds, may compete with food, fibre and feed production.
Measuring the environmental, economic and energetic performance of biofuels requires the consideration of the full life cycle of these products, i.e. from agricultural production and its use of various inputs (e.g. fertilizer and water) to the conversion of agricultural feedstock to liquid fuels and to the use of the biofuel in combustion engines.
In response to a call for considering all stages of biofuel production, the Life Cycle Assessment (LCA) methodology has been increasingly used to assess the potential benefits and/ or undesired side effects of biofuels. It studies and evaluates the environmental flows related to a product or a service during all life cycle stages, from the extraction of raw materials to the end of life.
The green house gas balances of biofuels
Quantifying how biofuels reduce GHG emissions and how energy efficient they are requires a life-cycle analyses (LCA). This holistic approach ideally takes full account of all stages of the production and use of a biofuel, including the GHG emissions and energy efficiencies associated with the resources required for its production.
As a rule of thumb, the life-cycle energy balance improves and global warming potential decreases when cultivation is less intensive, particularly with less fertilizer and less irrigation, and if the end product is straight vegetable oil rather than biodiesel. The energy-efficient use of the by-products also significantly improves the sustainability and environmental impact of biofuels.
Life-cycle-assessments (LCA) of biofuels show a wide range of net greenhouse gas balances compared to fossil fuels, depending on the feedstock and conversion technology, but also on other factors, including methodological assumptions. For ethanol, the highest GHG savings are recorded for sugar cane (70% to more than 100%), whereas corn can save up to 60% but may also cause 5% more GHG emissions. The highest variations are observed for biodiesel from palm oil and soya. High savings of the former depend on high yields, those of the latter on credits of by-products.
Life-cycle-assessments (LCA) of biofuels show a wide range of net greenhouse gas balances compared to fossil fuels, depending on the feedstock and conversion technology, but also on other factors, including methodological assumptions. For ethanol, the highest GHG savings are recorded for sugar cane (70% to more than 100%), whereas corn can save up to 60% but may also cause 5% more GHG emissions. The highest variations are observed for biodiesel from palm oil and soya. High savings of the former depend on high yields, those of the latter on credits of by-products. Negative GHG savings, i.e. increased emissions, may result in particular when production takes place on converted natural land and the associated mobilisation of carbon stocks is accounted for. Land conversion for biofuel crops can lead to negative environmental impacts including implications such as reduced biodiversity and increased GHG emissions.
Efforts to find sustainable, renewable sources of energy are growing and at the center of that trend is the switch from fossil fuels to crop-based biofuels. However, there are big differences. While corn-derived ethanol is among the least efficient, most environmentally damaging, and overall least sustainable biofuel feedstock, jatropha in comparison earns green credentials and can be grown on marginal land without replacing food crops.
Not all biofuels are created equal
The main findings for soybean biodiesel show wide variation, ranging from significant improvements to considerable net worsening. The main reasons which explain such huge differences are the agricultural yields and the assumptions made on allocation of impacts and the fate of glycerine.
Comparative figures for rapeseed range from a minimum benefit of approximately 20% to a maximum of about 80% compared to conventional diesel, with most studies converging around the 40-60% interval.
Ethanol from sugar cane produced in the tropical/sub-tropical regions such as Brazil, southern Africa and India, has excellent characteristics in terms of economics, CO2 reductions and low land use requirements. Ethanol from sugar cane can allow GHG emission reduction of over 70% compared to conventional gasoline. Higher values (also beyond 100%) are due to credits for co-products in the sugar cane industry. This reflects the recent trend in Brazilian industry towards more integrated concepts combining the production of ethanol with other non-energy products and selling surplus electricity to the grid.
Palm oil based diesel compares favorably to conventional diesel, in terms of GHG emissions. However, if previously non-cultivated areas are converted for palm oil production, the net resulting balance can be dramatically negative. Results change from 80% improvement for palm oil from cropland to over -800 and even -2000% with palm oil from cleared rainforest and cleared peat forest respectively.
In direct comparison, Jatropha planted on barren land in South East Asia scores significantly better than all biofuels referenced above. Growing jatropha on degraded wastelands with minimal fertilizers and irrigation will have the most positive environmental impact among all known biofuel crops.
In terms of land use, energy input, production costs and by-products, Jatropha is the most efficient and sustainable non-food biodiesel crop. Given its specific characteristics, we believe that Jatropha is one of the best candidates for future biodiesel production and will become the plant of choice for renewable energy generation from biomass.
The type of land used for biofuel production naturally affects the environmental performance of these fuels. JATRO favors the use of tropical and subtropical areas not currently used for crop production, i.e. either degraded land or land with low nurture values. Jatro only targets marginal, idle lands which are unsuitable for food production and poor in biodiversity.
JATRO believes that the land availability and food needs will limit the growth in conventional European and US based biofuels production based on sugar, cereals (wheat, corn), soybeans, and seed crops (rape, sunflower).
European biodiesel production based on rapeseed and sunflower seeds cultivated on arable land is not economically viable. The expansion of biodiesel production in wheat exporting countries has already diverted land from wheat and slowed the increase in wheat production. Indeed, biodiesel from rape and sunflower seeds in Europe and ethanol based biofuels in America are produced on land that alternatively could be used for food or feed production, and hence have the potential to negatively impact the supply of those products. In comparison, Jatropha crude oil produced in tropical regions has a considerable comparative advantage over those biofuels derived from agricultural crops in temperate zones.