Food crops vs. Fuel crops: perspectives and policy options

PIETRO LANZINI*

Abstract

The paper investigates if and to what extent a shift towards “fuel crops” production would have beneficial impacts on the environment, focusing on the “competition for land” issue. The question is whether an increase of biodiesel and bioethanol production would hinder the “food crops” production, as a consequence of land scarcity, with detrimental backlashes such as deforestation, harshening of undernourishment emergency in developing countries, and so on.
Given the absence of an universally accepted answer to such a broad question, the paper proposes the points of view and scientific instances of both “doomsayers” and optimists, highlighting common ground where possible, such as in the call for an increase of productivity of crops (to be achieved by traditional or innovative methods).
After an analysis of the specific Brazilian case, where both benefits and backlashes of the booming biofuel industry are investigated, the report ends with an overview of current policy options that are being implemented in developed as well as developing countries, and with a hint to an issue that is beginning to gain great public attention: perspectives on biofuel certification.

Keywords: biofuel, competition for land, Jatropha.

 

Introduction: biofuels trends and drivers

To date, fuels from crude oil supply most of the worldwide demand for primary energy. Such dependence is clearly not ideal; not only because crude oil reserves are limited and unevenly distributed in the world, with the most important reserves in politically unstable regions, but also because of environmental issues. On the wave of such concerns, there is a momentum for throughout discussing the pros and cons of alternative energy sources, and the present paper specifically focuses on one of them: biofuels. Biofuels are a renewable energy that encompass a broad range of products, varying significantly in terms of characteristics and environmental impacts. The following table illustrates a list of biofuels, as in the EC Directive 2003/30:

 

We will especially focus our attention on liquid fuels from biomass, namely bioethanol and biodiesel, being respectively ethanol produced from biomass and/or the biodegradable fraction of waste, and a methyl-ester produced from vegetable or animal oil (such as soybeans and oil seeds).

Biofuels production of 33 billion litres in 2004 is still small compared to 1,200 billion litres of gasoline produced annually worldwide, but it is on the rise. Brazil has been the world’s leader (and primary user) of fuel ethanol for more than 25 years, producing slightly less than half the world’s total in 2004. Total world production of bio-diesel in 2004 was more than 2 billion litres, of which more than 90% was produced in the EU25 (Eurobserver 2005). The size and continuous growth of biodiesel and fuel ethanol productions are well represented by the following figures:

The increasing trend is not typical of recent years only, as we note taking a look at the biofuel production over the past 30 years (Worldwatch institute 2006)¹:

As far as biofuel producing countries are concerned, Brazil and the United States play a crucial role in the bioethanol industry, while biodiesel industry is greatly developed in Europe, as previously anticipated, and especially in Germany (Worldwatch Institute 2006):

There are many drivers supporting such international development of biodiesel production. While the list is not exhaustive, we summarize some of those drivers below:
 

o The adoption of national-level targets in a number of countries for blending biofuels with petroleum fuels in response to concerns about energy security and GHG emissions. Both ethanol and biodiesel can be easily incorporated into blends and they can be used in existing motor fuel distribution networks without having to modify vehicles to any great extent.

o The potential for achieving reduction in GHG emissions and improving vehicle performance is regarded as a significant factor influencing biofuel use particularly in industrialized countries with reduction commitments under the Kyoto protocol.

o Enhancing rural economy in terms of added agro products and new markets as well as employment generation particularly in developing countries.

o New opportunities for trade with possibilities of exports from developing countries which are expected to produce biofuels at a relatively cheaper cost because of their lower labor costs.

o Soil protection and land reclamation can be enhanced, as growth of biomass feedstock can help restore degraded land, such as agricultural lands withdrawn from food production

o Great potential of turning a problem into a resource, as far as waste management is concerned: as millions of tons of waste and residues are produced every year, such stock of materials ranging from municipal solid wastes to animal wastes, from straw to rice husk and so on can be used to produce energy.

Biofuel production: feedstock and pathways


Biofuel can be produced from a wide range of crops and materials, as feedstock varies significantly worldwide in relation to the climatic and geographical features of a given region and to the technological and economic background of such areas.

Biodiesel can be produced, for instance, from rapeseed, soybeans, sunflowers and coconuts, while bioethanol comes from grains or seeds (like corn, wheat or potato), sugar crops (sugar beets and sugarcane) or even from lignocellulose biomass. Corn and soybeans are primarily grown in the United States, while rapeseed is grown primarily in Europe, sugar cane in Brazil and palm oil in South-East Asia. Moreover, biodegradable outputs from industry, agriculture, forestry and households can be used to produce bioenergy, as well (e.g.: straw, timber, sewage, biodegradable waste etc), representing a paramount opportunity for future developments of a “sustainable” biofuel industry..

There is no unique production process to transform feedstock and raw materials into biofuels, as to date there are different pathways: some of them are well established, while others are still in early stages of their development, needing further time and investments in R&D in order to achieve economic and commercial readiness. A brief overview of some of current and potential pathways is hereby presented (source: UK DfT)²:

o Biodiesel can be produced from a variety of vegetable oil feedstock such as rapeseed oil, soybean oil and sunflower oil. Rapeseed currently accounts for over 80% of global biodiesel production, while sunflower oil accounts for 13%. The process starts with oilseeds being crushed to produce oil, which after filtering is mixed with ethanol or methanol. The resultant esterification reaction produces fatty acid methyl esters, which are the basis for biodiesel. The technology for extracting oil from oilseeds has remained the same for the last 10-15 years and is not likely to change significantly. Similarly, biodiesel production from the oil is a relatively simple process and so there is little potential for efficiency improvement. Research is underway as to improving the utilization of co-products.

o Bioethanol can be produced by wood and straw, using acid hydrolysis and enzyme fermentation. This process is technically feasible but is complex and expensive and there are few industrial examples. Ongoing research and development in the US aims to address cost issues and develop a more efficient process. This is thought by many to be a step on the way to the eventual goal of an enzyme hydrolysis process.

o Bioethanol from wheat from malting and fermentation provides for a similar process to that for other methods producing bioethanol by fermentation, but an initial milling and malting (hydrolysis) process is necessary. The wheat is first crushed or milled. In its passive form, malting is a process by which under controlled conditions of temperature and humidity, enzymes present in the wheat break down starches into sugars.

o Bioethanol from corn using fermentation is similar to the process for wheat, but with small differences in the initial processing of the corn. Firstly, the corn must be milled, either by wet milling or dry milling. The milling produces co-products of residues which can be sold as animal feed. Enzymes are used to break down the starches in the corn into sugars which are then fermented and distilled using the same process as for wheat.

o Bioethanol from sugar cane or sugar beet using fermentation is probably the simplest of all the processes for producing bioethanol by fermentation. The harvested sugar cane or sugar beet is crushed and then soluble sugars are extracted by washing through with water.

o In perspective, biodiesel from wood or straw might be produced by using gasification and Fischer- Tropsch process. First pioneered for the purpose of converting solid fuels, mainly coal to liquid fuels, in countries where there was a very limited indigenous supply of oil, it starts up with the gasification of the feedstock to a "synthesis gas", which is primarily a mixture of hydrogen and carbon monoxide. This gas can, in turn, be converted to liquid fuel in the Fischer-Tropsch reactor, which makes use of a catalyst (usually iron-based). The reactor also produces significant heat which can be used to generate electricity as a significant co-product of the process. There is little information in the literature about Fischer-Tropsch processing of biofuels, although the process should be very similar to the fossil fuel process. The key challenge for biofuels is to adapt and optimize the whole system to a scale that is appropriate to the availability of the biomass feedstock.

o Bioethanol from wood or straw could be produced by enzyme hydrolysis and fermentation. Even if this process is not yet developed enough to be put into practice, it is expected to be commercially viable by 2020. It is essentially similar to the process in which ethanol is produced from wood and straw through acid hydrolysis and fermentation, except that enzymes instead of acids are used for the hydrolysis process.

Environmental benefits of biofuels

The use of biomass energy has many unique qualities that provide environmental benefits. It can help mitigate climate change, reduce acid rain, soil erosion, water pollution and pressure on landfills, provide wildlife habitat, and help maintain forest health through better management.

> Biofuels have a number of advantages over conventional fuels. First and foremost, they come from a renewable resource; moreover, GHG emissions will be reduced as the fuel crops absorb the CO2 they emit through growing.
> The use of ethanol-blended fuels as E-85 (85% ethanol and 15% unleaded gasoline) can reduce the net emissions of GHG up to 25%, thanks to carbon sequestration during corn farming, which more than offsets GHG emissions during corn farming and ethanol production. Ethanol-blended fuel as E-10 can reduce GHG up to 3.9%³.
> B20 bio-diesel reduced total hydrocarbons by up to 30%, Carbon Monoxide up to 20%, and total particulate matter up to 15%⁴.
> Biodiesel reduces emissions of carbon monoxide (CO) by approximately 50 % and carbon dioxide by 78 % on a net lifecycle basis because the carbon in biodiesel emissions is recycled from carbon that was already in the atmosphere, rather than being new carbon from petroleum that was sequestered in the earth's crust. (Sheehan, 1998)⁵
> Farrell et al. (2006) estimate that the fuel cycle for energy from grain ethanol requires up to 95% less petroleum than the fuel cycle for an equivalent amount of energy from gasoline⁶
> A study by the US Department of Energy has found that bio-diesel production and use, in comparison to petroleum diesel, produces 78.5% less CO2 emissions⁷
> The following figure from EPA studies shows how biodiesels are less harmful on the environment from the point of view of emissions⁸

> Biodiesel helps to preserve and protect natural resources. For every one unit of energy needed to produce biodiesel, 3.24 units of energy are gained. This is the highest energy balance of any fuel.
> Biodiesel is nontoxic and biodegradable. Tests sponsored by the United States Department of Agriculture confirm that biodiesel is ten times less toxic than table salt and biodegrades as fast as dextrose (a test sugar)
> Some studies, scuh as the WRI’s⁹, highlight a sort of trade/off between different environmental effects: an increase in the production of biofuels, namely ethanol, will have different impacts according to the environmental issue we take into account (for further information and details on the study, please visit http://pdf.wri.org/beyondrfs.pdf ):

However, there is no general agreement whether bio-fuels are actually less “polluting” than petro-fuels, if we take a broader perspective. For example, global warming pollution savings from biofuels can vary substantially depending on crop growth techniques and pathways, and that is the reason why there are many ongoing activities in such direction, like Environmental Defense Fund working with farmers and commodities groups to develop a low-carbon certification program for biofuels. Moreover, there are many complex interactions and overlapping so that an improvement in a given indicator might imply a worsening of another, with a trade off whose overall balance is difficult to assess.
If we look at the following figure, we note how while there are considerable advantages in terms of reduced greenhouse gas emissions, there are also disadvantages due to the contribution to acidification and eutrophication (SRU 2005).

Last but not least, we have to keep in mind that it is not only the fuel itself that has to be taken into account, but all the production and consumption process as a whole.
We have seen how an argument used to support ethanol as a "green" fuel is actually that it is renewable, and that by burning it as transportation fuel the carbon dioxide thus released is absorbed by the plants from which the alternative fuel is produced. From such perspective, fuel ethanol consumption could be considered CO2 neutral. However, GHG debits arise during the whole process of crop production to consumption, due to the use of agricultural chemicals, fuelling of farm machinery, transportation activities, crop processing and so on. All this obviously involves the use of fossil fuels (and hence GHG emissions), and the same goes for the net energy value of ethanol, where results are very much dependant on the nature of the feedstock and the source of power used for the production process.

This skepticism will be better addresses in the next section, taking into account all the pillars of sustainable development and hence focusing also on other dimensions such as the social one.



Can biofuel development lead to “competition for land” and other backlashes?


There is indeed an ongoing discussion on whether an increase in biofuel production might impact upon land-use patterns and deforestation, undermining availability of food and leading to a harsh competition for land. By diverting agricultural production away from food crops, energy crop programmes are feared to “compete” with food crops in a number of ways, ranging from the land use itself to rural and infrastructure investments, from water and fertilizers use to skilled labor, and so on. To date, there is actually no general agreement upon the consequences of an intensive development of bio-fuel oriented crops. We will briefly describe the rationale of “optimists” and “pessimists”, trying to find some common ground and to stress some policy options that might be useful to achieve broadly agreed-upon solutions that address environmental, social and economic needs at once.

Pessimists:

First of all, we should stress that the problem linked to biofuels sector development is multi-faceted, as there is the need to address many issues that are deeply interrelated. Concerns range from the scarcity of available land that might hinder food production to the possible exploitation of forest areas, with subsequent damages for wildlife and bio-diversity at large; from an unprecedented pressure on soil and water resources to the social consequences that agro-energy giants development might bring to small farmers and agricultural communities, and so on.

And such concerns are made even greater by the awareness that current demographic trends will put an increased pressure on agriculture, as to adequately feed a population that according to FAO figures is supposed to increase by more than 3 billion by 2050. Given such framework, will it be viable, from both a practical and ethical point of view, to set aside part of arable lands for biofuels?

Human society is already farming about 37 % of the global land area, and using almost all of the good-quality land. Additional farmland will have to come at the expense of forest and wild species, and is likely to incur heavy penalties in terms of soil erosion, drought risks, and endangered wild species (Avery 2006). As a matter of fact, if present arable land won’t be sufficient to address the need of land for biofuel oriented agriculture, producers will inevitably turn to areas that are nowadays unexploited due to their poor quality from an agricultural perspective.

However, many studies stress that land too poor to farm has contained virtually all of the world’s wildlife species from time immemorial, while on the other hand best croplands never had many wild species. For instance, a national park in the Peruvian Amazon contains more than 1,300 plant species, 332 bird species, 131 species of amphibians and reptiles, 70 different species of non-flying mammals, plus thousands of species of insects, and a few square miles of tropical forests may contain more above-ground species than all of North America. Expanding fuel crops onto poorer-quality land might therefore take a devastating toll on wild species displaced or lost (Avery 2006).

Indeed, this is consistent with the concerns emerging from a recent research carried out by the Worldwatch Institute. Not only it raised the concern that if fuel crops are grown on ecologically fragile lands, this might accelerate soil erosion and the depletion of aquifers; but also, biofuel crops could have negative impacts on local ecosystems and biodiversity, as “ecologists point with alarm to the massive Brazilian soybean crop that is encroaching on the outer fringes of the Amazon Basin”.

Worldwide, during the last decade per capita available cropland decreased 20% and irrigation 12% (Brown 1997)¹⁰. Indeed, Agricultural water use is a serious concern not only in developing countries, but also throughout Europe and especially in southern parts of the continent; according to the EEA, in such areas water availability is low and varies from year to year, and increases in irrigated land have contributed to water scarcity, with the lowering of water tables and water levels in rivers and lakes. To use EEA words, “the substantial rise in the use of biomass from agriculture, forestry and waste for producing energy might put additional pressure on farmland and forest biodiversity as well as on soil and water resources”.

As suggested before, the booming of biofuels might have negative repercussions not only for the natural environment and for the stock of food available, but also as far as economic and social dimensions are concerned. Warnings in such direction are being given by many organizations, such as Planet Ark: its analysis on the issue stresses how the mushrooming of mono-crops for bio-fuels around the globe, through raising the risk of greater competition for land and feedstock, is actually threatening to lift prices of both bio-fuels and food. The large-scale promotion of bio-energy relying on intensive cash crop monocultures could lead for instance to a sector dominated by a few agro-energy giants, without any significant gains for small farmers. There is hence little doubt that good planning will be needed to prevent the competition for land between energy and food crops.

Here is some other data highlighting how competition for land might be on the horizon, if biofuel production is to be increased, at current efficiency patterns:

• The grain that could feed a person for one year is required just to fill the petrol tank of a Range Rover (McNeely)¹¹

• Given current road transport consumption in the UK (around 37.6m tonnes of petroleum products a year), a shift towards biofuels in the modest target of 20% by 2020 would not be sustainable in the near future. A production of biofuel based on rapeseed, the most productive oil crop to be grown in the UK, would consume almost all available 5.7m hectares cropland (Monbiot, 2004)¹². If the same thing is to happen all over Europe, the impact on global food supply will be catastrophic so that the net balance would tip from net surplus to net deficit. If, as some environmentalists demand, it is to happen worldwide, then most of the arable surface of the planet will be deployed to produce food for cars, not people.

• Many believe that there is a sort of trade off between nature conservation and biofuels. The following figure, for instance, represents the crop coverage needed to meet the EU 2010 target of 5,75% biofuel¹³ :

In the “Basic” Scenario the minimum requirements of nature conservation law are meant to be taken into account, while in the Nature Conservation Plus Scenario nature conservation requirements receive greater consideration.
If we are to manage land according to current sustainability standards such as in the Nature Conservation Plus Scenario, the EU target would be missed by a wide margin. Instead of the 5.75% fuel share, this variant would produce 0.78% sugar beet and ethanol, 0.35% wheat and ethanol and 0.31% biodiesel, being this represented by the line in the figure.

• It is feared that meeting a relevant increase in biofuels demand in areas such as the EU and the USA using conventional crops such as grain, sugar or oil seed crops might require a vast allocation of cropland, as shown by the following table (IEA 2004):

• Contrarily to what generally agreed upon, some believe that biofuels have a very poor energy balance. Moreover, in some cases such as corn ethanol, the fuel would be actually produced at an actual net energy loss. Another case is that of soybeans:¹⁴ an acre of U.S. soybeans is worth only 52 gallons of biodiesel per year. Each soybean acre produces only 40 bushels of soybeans, or one-third the grain yield of corn. Each bushel of soybeans produces 1.4 gallons of biodiesel, with 93% of diesel’s energy.

• As regards for instance corn grown in the US, we can note from the following figures that while the yield itself is very abundant, the overall energy balance is pretty poor, if compared to other crops such as sugar cane¹⁵

• Pimentel¹⁶ affirms that producing ethanol from US corn actually displays a negative energy balance, as “about 29% more energy is required to produce a gallon of ethanol than the energy that actually is in the gallon of ethanol produced”:

• The point is that when all of the elements required to produce biomass-based liquid fuels such as ethanol and biodiesel are added together, the energy requirements for production far exceed the energy produced.
...corn requires 29% more fossil energy than the fuel produced; [...] soybean plants requires 27% more fossil energy than the fuel produced [...]¹⁷
In assessing inputs, the researchers considered such factors as the energy used in producing the crop (including production of pesticides and fertilizer, running farm machinery and irrigating, grinding and transporting the crop) and in fermenting/distilling the ethanol from the water mix.
• This is consistent with the conclusions drawn by McNeely: due to the use of fossil fuels at every stage of the production process (from cultivating to processing and transporting), growing maize appears to use 30% more energy than the finished fuel produces. Moreover, McNeely states that using ethanol rather than petrol reduces total CO2 emissions by only 13%, because of the pollution caused by the production process.
• Projected world power requirements in 2052 will rise to a total of 22 to 42 trillion watt-hours (Avery 2006). Producing this from crops could require as much as 80% of the Earth’s total land area, so that we would need to be energy-cropping areas such as the Gobi Desert, the Amazon River basin or even northern Siberia.
• Credit Suisse says that a rise in global bio-diesel share to two percent of the total amount of diesel used in transportation would completely deplete current vegetable oil stocks, and arable land that would otherwise have been used to grow food would instead be used to grow fuel (Exchange Magazine, 2006).

Optimists

On the other hand, there are other voices that are skeptical about the possible detrimental consequences of bio-fuels for arable land and food stocks, and for sustainable development at large. This large party believes that biofuel is the solution and not the problem.

First of all, there is evidence that world population is of course growing, but at a decreasing rate, and such trend will continue in the next decades so that global population should stabilize somewhere around the middle of the 21^st century.
The following figures, taken from UN “The World at six billion”, clearly show how, even if global population is still in the increase, the trend has changed as growth rates are rapidly declining:

Moreover, it appears that the world is not “running out of food”. Even in the scenario of an increased population, there would still be room to divert some of the production towards biofuels.

This so-called 'food versus fuel' controversy appears to have been exaggerated in many cases, as the world's real food situation displays an ever-increasing food surplus in most industrialized and a number of developing countries.

We can consider for instance food shortages experienced by Brazil a few years ago. The blame had been put on the ProAlcool programme (fuel ethanol), but a closer examination does not support the view that bioethanol production adversely affected food production. Brazilian agricultural production has always kept ahead of population growth: in 1976 the production of cereals was 416 kg per capita, and in 1987 -- 418 kg per capita. Of the 55 million ha of land area devoted to primary food crops, only 4.1 million ha (7.5 per cent) was used for sugarcane, which represents only 0.6 per cent of the total area registered for economic use (or 0.3 per cent of Brazil's total area). Of this, only 1.7 million ha was used for ethanol production, so competition between food and crops is not significant.
The world already grows more than enough food to feed everyone. Yet about a billion people still don't have enough food to meet basic daily needs. There is more food per capita now than there's ever been before. It is the inequitable economic system, and not overall food scarcity, that should be held accountable.
The following table is taken from 12 Myths about hunger¹⁸:

As far as the energy balance is concerned, many believe that advances in technology have improved production efficiency, giving all current biofuels a positive fossil energy balance. Not only is the efficiency of the conversion process advancing steadily, but bioenergy is increasingly being used for feedstock processing as well. Both approaches reduce the amount of fossil fuels used to convert crops into biofuels. (Wordlwatch Institute 2006):

We can take a closer look of the energy balance of biofuel by focusing on a specific case, such as that of sugarcane ethanol in brazil: the following figure shows as, even taking into account all the energy used during the process, the output/input ratio is overwhelmingly positive, being around 8,3 or more depending on the assumptions that are beneath the calculations (Coelho 2005).

The question that most researchers ask themselves is “how much fuel can we grow? How much land will it take?”. There is widespread fascination with high yielding oil crops, particularly oil-bearing algae, with oil palms running second. It seems obvious that the highest-yielding crops will produce the most energy from the least amount of land. But high yield is not the only factor in farming, and it may not always be the most important factor. It can make more sense for a farmer to grow a lower-yielding crop if it has more useful by-products or requires fewer inputs or less labor or it fixes more soil nitrogen for fertilizer or it fits a crop rotation better.

The challenge would therefore be that of increasing substantially the production of bio-fuels by using innovative feedstock, processes and technologies, which are both competitive and sustainable. Also, we have to keep in mind that agricultural and forestry systems currently exploit only part of their production, i.e. “primary” products, while they leave unexploited significant “residual” quantities. Hence, the use of both the primary and the residual resources through integrated and sustainable pathways should be promoted.
 

Bridging the gap

In seeking to bridge the large gap between the optimists and pessimists, there may be some common ground on high-yielding oil crops, particularly oil-bearing algae, with oil palms running second. It seems obvious that the highest-yielding crops will produce the most energy from the least amount of land. Indeed, we have to note that the yields of a given crop can vary extremely significantly, due to a number of reasons ranging from the quality and the geographical position of the land, to the type of pesticides and fertilizers used (if any), from the irrigation system to the eventual genetic modification, and so on.

If we consider for example the fertilizer issue, it should be stressed that strategies differ significantly around the globe. There are areas where a little amount is more than enough to secure high crop yields, while elsewhere (such in Brazil) most arable lands must be intensively fertilized, as this is vital for key crops like sugarcane and soybeans¹⁹. Planning efforts should therefore focus on choosing the best available cropping solutions for each region and land type. The following table summarizes the yield ranges from some Italian crops suitable for biofuel production²⁰.

And the same goes for crops grown in developing countries, where the yields vary significantly as different factors (rainfall, soil acidity etc) play a relevant role. The following picture shows the stem yields of sweet sorghum in different Zambia sites:
 

Given the broadness of such ranges, it becomes of paramount importance to achieve a high efficiency in cropping techniques, so that a relatively small area of arable land will provide a fair amount of biofuels.

Not only traditional crops should be taken into account, as the future of biofuel might be linked to the exploitation of “new” plants such as the jatropha, very common in India and expanding in some African areas. Jatropha is particularly interesting as it establishes itself easily even in arid and waste land (areas with rainfall as low as 200mm per year ), where other crops would perish (and such land is often abundant in the poorest areas of the developing world). Jatropha plants produce seeds with an oil content of 37%, but there are also reports of getting oil yield as high as 50% from the seed (PCRA data). The oil can be combusted as fuel without being refined. It burns with clear smoke-free flame, and has been tested successfully as fuel for simple diesel engine. Moreover, the oil also contains insecticide which can be used as a rewarding byproduct²¹. However, jatropha yields vary significantly, as seed production ranges from about 2 to over 12.5 t/ha/year, depending on many factors such as low and high rainfall areas. If we consider average yields, we note that Jatropha has better yields than all other biodiesel feedstock, with exception of palm oil (Worldwatch Institute 2006).
 

Other studies evidence an even better performance of Jatropha Curcas:

Some further advantages of this plant are listed below:²²
 

> Jatropha is a drought resistant perennial living up to 50 years. The tree grows up to a height of 3 meters, which means harvesting is an easy task.
> It takes two years for a 'Jatropha' sapling to begin producing seeds, and they can produce seeds for up to 40 years.
> The plant is not exploited or damaged by animals and birds.
> Jatropha holds promise for rural prosperity to the farmers, farm-labourers and women in terms of employment and income generation.
> Jatropha adds richness to the environment by abating carbon, alleviating pollution, conserving oil and preventing soil erosion and desertification.
> The residue obtained after removing oil from seed is used as a fertilizer for erosion soil.

If we focus on India, we notice how the country has 60 million hectares of waste land, of which it is estimated that half might be used for Jatropha cultivation (IFPRI 2006).
The cost of producing biodiesel from Jatropha is between US$0.43 and US$0.54 per liter (IFPRI 2006). In order to exploit such great potential, in February 2006 the Energy and Resources Institute (TERI) of India announced to be about to undertake a 10-year project, in conjunction with BP, to cultivate 8,000 hectares of wasteland with Jatropha and install the equipment necessary to produce 9 million liters of biodiesel a year. Also, the project pledges to include a thorough analysis of the social and environmental impacts of the approach.

However, Jatropha has also some disadvantages, which can be briefly outlined as follows:²³

1. The energy ratio (output/input) of 1.5 is low compared to other energy sources, but is still higher than other biodiesel sources.
2. This shrub is not frost-resistant.
3. Outputs from crops can widely vary, from less than 1 ton per hectare to 6 tons.

Moreover, due to several different toxic principles including a lectin (curcin), phorbol esters, saponins, protease inhibitors and phytates, neither the seeds nor the press cake nor the oil of Jatropha curcas can be used for human or animal nutrition; even if the plant is not intended for human consumption, its toxicity might represent a problem, especially if grown in areas close to food crops plantations²⁴

While many biofuel critics point the finger at the extensive agricultural resources needed to produce a gallon of fuel, we should remember that the technology is still in its infancy. The petrochemical industry had about a half-century head start, so it is not surprising that gasoline is more efficient now. However, there are ongoing efforts to increase crop yields, this being the winning strategy to achieve a synergic between environmental and economic efficiency (for example, companies such as DuPont and Monsanto are learning how to optimize crop yields for ethanol and biodiesel production).

The following figures illustrate the steady improvements in US crop yields over the past 50 years²⁵:

Increasing the amount of food grown per acre has allowed U.S. agriculture to produce more food and fiber without corresponding increases in farm acreage. The total acreage used for agricultural production has declined slightly over the past half-century.

This increasing trend is typical of most regions, and not only the US. We note from the following figure that even Brazil has experienced an increase in crop yields over the past decades.
 

Next we present some data showing how both crop yields and conversion yields are improving, and are expected to maintain these trends in decades to come²⁶:

■ The average yield for corn in the US has increased from 5.7 to 7.9 metric tonnes per hectare over the last 15 years (about 2% per year).
■ The USDA projects that corn yields per hectare will improve by another 10% over the next ten years, and that soy yields will improve by about 5%.
■ Between 1975 and 2000, sugarcane yields in the Brazilian São Paulo region rose by 33%, ethanol production per unit of sucrose rose by 14%, and the productivity of the fermentation process rose by 130% (IFPRI 2006)²⁷.
■ Conversion yields are also assumed to improve, at about 1% per year for ethanol (litres per tonne of feedstock), and at a slower rate (0.3%) for biodiesel, since the process of crushing oil-seeds and converting to methyl ester (biodiesel) is not likely to benefit as much from technological improvements or scale increases (USDA, 2002; IEA, 2000a).

Efficiency in crop yields, besides traditional expedients such as tailoring the crop rotation to the specificities of the arable area or optimizing irrigation/fertilization procedures, will be gained through seed hybridization as well as through genetic modification, obviously scrutinized for all of the potential health ramifications.

Once again, we have to point out as there is no general agreement over the real desirability of such efforts, as many fear that the outcome of twisting natural laws might be unpredictable. For instance, the Swiss biotech firm Syngenta is developing a genetically engineered maize that can help convert itself into ethanol by growing a particular enzyme. Other companies are designing trees that have less lignin, the strength-giving substance that enables them to stand upright, but makes it more difficult to convert the tree's cellulose into ethanol. Some environmentalists are worried that these altered trees will cross-breed with wild trees, resulting in a drooping forest rather than one that stands tall and produces useful timber and wildlife habitat²⁸. Moreover, there is some concern that genetically modified products are not suitable for human consumption. It would be therefore very difficult to avoid and control eventual cross breeding, which might occur not only by tampering attempts, but also by simple natural phenomenon such as wind transferring seeds for hundreds of miles.

The Brazilian case: among successes and challenges

The Brazilian case is a success story which is often used to characterize the biofuel industry; however, we will point out some flaws that are still hindering the achievement of a truly sustainable scenario.

The use of ethanol to fuel automobiles was initiated partially in response to the oil shock of 1973, and as an alternative to oil to promote self-sufficiency. In 1975, the government created the Brazilian National Alcohol Program to regulate the ethanol market and encourage the production and use of fuel ethanol. The program guaranteed that all gasoline sold in the country would be blended with 22% anhydrous ethanol and that the pump price would remain competitive with gasoline. Past sugarcane crop problems have slightly altered the percentage of ethanol in Brazilian gasoline, however, mandated levels have usually remained at around 20%. The program successfully reduced by 10 million the number of cars running on gasoline in Brazil, thereby reducing the country's dependence on oil imports.

The following table summarizes the ethanol production process from sugarcane:
 

The alcohol industry, entirely private, has invested heavily in crop improvement and agricultural techniques over the past decades. As a result, average yearly ethanol yield increased steadily from 300 to 550 m³/km² between 1978 and 2000, or about 3.5% per year.

The following data apply to the 2003/2004 season²⁹.

Ethanol-only cars were sold in Brazil in significant numbers between 1980 and 1995; between 1983 and 1988, they accounted for over 90% of the sales. 80% of the cars produced in Brazil in 2005 were dual-fuel, compared to only 17% in 2004.
Domestic demand for alcohol grew between 1982 and 1998 from 11,000 to 33,000 cubic metres per day, and has remained roughly constant since then. In 1989 more than 90% of the production was used by ethanol-only cars; today that has reduced to about 40%, the remaining 60% being used with gasoline in gasohol-only cars. Both the total consumption of ethanol and the ethanol/gasohol ratio are expected to increase again with deployment of dual-fuel cars.
The improvement in air quality in big cities in the 1980s, following the widespread use of ethanol as car fuel, was widely evident; as was the degradation that followed the partial return to gasoline in the 1990s.
If we were to point out the most relevant policies that spurred Brazil’s success in the biofuel industry, we should mention a broad set of factors ranging from requirements for the industry to produce cars using neat or blended biofuels to the subsidies for biofuels during initial market development; from the opening of the electricity market to renewable energy–based independent power producers in competition with traditional utilities to the support for private ownership of sugar mills, helping guarantee efficient operations, and so on (stimulation of rural activities based on biomass energy to increase employment in rural areas, etc).

There is evidence (IFPRI 2006) that in 1997 the ethanol sector employed about 1 million people in Brazil. While 35% of these jobs were temporary harvesting jobs employing many poor migrant laborers from the Northeast, 65% were permanent. Moreover, 300,000 people found an occupation thanks to jobs created indirectly by the ethanol industry.
Being most of these jobs simple and unskilled, the new situation created an opportunity for many poor rural people, and rural farmers took advantage of the situation, as well, since some 60,000 small farmers produce about 30% of the sugarcane in Brazil (even if, as pointed out later, there is no general agreement upon the actual benefits of the ethanol program for rural communities)

However, the ethanol program also brought a host of environmental and social problems of its own. Sugarcane fields were traditionally burned just before harvest and thus, the air pollution which was removed from big cities was merely transferred to the rural areas.

There is also widespread concern that the so-called soybean frontier is approaching the rainforests, meaning this that the Amazon and other green areas of Brazil are threatened by the rise in the cultivation of soybean for fuel purposes, which might lead to deforestation in order to obtain more arable land.
And the same goes for sugarcane cultures, even if many point out how these cultures are developing in areas that are far away from the Amazon region, thus not representing a threat to rainforest habitat³⁰:

A peculiar solution suggested by some³¹ is that “the rest of the world to pay them to leave their trees intact”. In other words, “avoided deforestation” should be included in a list of emissions-reducing activities that rich countries can sponsor to help meet obligations under the Kyoto protocol.
The International Institute for Environment and Development, has estimated that logging, and the subsequent use of the land cleared each year, in eight forested countries, would bring in $5 billion over a 30-year period. That translates into a benefit of $3.50 for every tonne of carbon dioxide released. So far rich countries have paid an average of $7 per tonne to reduce emissions in the developing world, under the Kyoto protocol. At that rate they could pay deforesters twice as much to leave trees alone as the latter get now for cutting them down.

It should be noted that some other nations are better addressing the issue, producing alcohol fuel with little harm on the environment thanks to advancements in fertilizers and natural pesticides that is eliminating the need to burn fields. And, thanks to condensed agriculture like hydroponics and greenhouses, less land is used to grow more crops.

As far as social implications are concerned, many detractors of the biofuel oriented policy affirm that the ethanol program led to widespread replacement of small farms and varied agriculture by vast seas of sugarcane monoculture. The consequence was a decrease in biodiversity and further shrinkage of the residual native forests (not only from deforestation but also through fires caused by the burning of adjoining fields). Moreover, the replacement of food crops by the more lucrative sugarcane caused a sharp increase in food prices over the last decade.
From the occupational point of view, since sugarcane only requires hand labor at harvest time, this shift also created a large population of destitute migrant workers who can only find temporary employment as cane cutters.

However, we should not overestimate the relevance of problems connected to biofuel production in Brazil. While some doomsayers believe that sugarcane cultivation will displace other crops, thus causing food shortages, we have to stress how these concerns seem to be groundless. Despite having the world's largest sugarcane crop, the 45,000 km² Brazil currently devotes to sugarcane production amount to only about 0,5% of its total land area of some 8.5 million km². In addition, the country has more unused potential cropland than any other nation³².

Spurring biofuels: an overview on current policy options

To date, many organizations and bodies are addressing the issue of biofuels development, both at national and international level. The United Nations Development Programme (UNDP) and the Food and Agriculture Organization (FAO), the World Bank and the International Energy Agency (IEA) are all active in supporting biofuels worldwide.

International cooperation is obviously to play a crucial role, if relevant results are to be achieved. We can mention for instance the Horizontal Technical Cooperation Program in agro-energy and bio-fuels, involving Brazil and other countries of the Americas, whose aims are assisting countries in Latin America and the Caribbean in developing agro-energy, generating employment and income, complying with environmental policy and bringing such countries to the forefront of the world’s biofuel industry.

Aware of the disputes over the effective eco-friendliness of such products, and conscious of the eventual backlashes that they might imply, we hereby highlight the directions on which the efforts are underway.

There are different sets of policy options that might spur the production on biofuels, overcoming the diffused skepticism on high production costs. Such options can be either fiscal/monetary or normative, and can be categorized into two types:

> Application incentives, supporting the sale, distribution and use of biofuels
> Production incentives, such as tax credits, grants and loans for biofuel producers

The following table summarizes some of current government support measures for Biofuels in selected countries³³:

In a recent paper, Gururaja³⁴ lists some policy options that are included in both the application and the production incentives sets:

Particular attention should be given to the efforts aimed at eliminating trade barriers, thus facilitating international trade in biofuels. There is a great potential for exports
from developing countries (such as Brazil, where ethanol costs are $0.1 to $ 0.2 cheaper than IEA countries) to developed ones, which might bring benefits to both sides. Governments may hence consider building trade regimes applicable to biofuels especially targeting the removal of trade barriers. Reforming the tariff structure is the first step to adopt, in such direction, and international cooperation will be needed to foster such process, and biofuel trade at large.

The European Commission itself is devoted to bolstering the production and uptake of biofuels The commitment is multi faceted, and efforts are to be made in different directions³⁵:
 

- Support biofuel demand (reference values are 2% of market share in 2005 and 5,75% in 2010). Some Member States adopted imposing measures, so that fuel supply companies must market a certain percentage of biofuels.

- Exploit environmental advantages. For instance, there is an ongoing discussion viable paths of accounting biofuels in terms of CO2 emissions reduction

- Enhancing commercial opportunities. Namely, assessing the implications of a possible distinctive trade code for biofuels. Besides, there is already an ongoing liberalization process, given the Doha Round on one hand, where bioethanol will undergo a tariff reduction, and the EU/Mercosur deal on free trade on the other.

- Supporting developing countries. For instance, the EC is willing to support developing economies in overcoming the hindrances they are facing after the European sugar reform. On the basis of a case-by-case analysis of each country specificities, this might encompass also directly supporting the production of bioethanol.

- Supporting R&D, as the goal is that of abating costs by 30% by 2010, in the wake of the success of past projects such as EUROBIODIESEL, and the promising kickoff of new ones such as RENEW and NILE.

Also developing countries are addressing the issue of supporting biofuel industry, and Tanzania is a case in point.³⁶ The development of a strong biofuels sector in Tanzania will initially require supportive policy pressure. We hereby list some of the measures suggested by the study, encompassing both traditional and non-traditional policy approaches:

> Fuel Tax Incentives could bolster the use of biofuels, making them more price-competitive with petroleum fuels. Fuel excise taxes represent a significant percentage of the price Tanzanians pay for fuels, so that exempting alternative fuels from part of such burden would be a powerful tool for ‘leveling the playing field’. Reduced government revenues could be avoided by adjusting the taxes on all fuels, so that overall revenues remain constant.

> Carbon-based Fuel Taxes might support biofuels, as they tax the externality (carbon) directly

> A CO2 emission trading system would cap the quantity of emissions allowed by various emitters, and the right to emit becomes a tradable commodity.

> Clean Development Mechanism (CDM) consist of one country engaging in projects through which an entity partially meets its domestic commitment to reduce GHG levels by financing and supporting the development of a project in another country.

> Governments can also implement fuel standards as a mechanism for altering the transport sector fuel mix, setting a minimum fuel content of non-petroleum (or renewable) fuel and hence using regulation to drive the market.

> Incentives for Investment into Biofuels Production Facilities are needed, as required investment in commercial scale production facilities represents an important barrier to the development of a biofuels market.

> Also, the focus is to be put on trade policies to remove barriers to international biofuels trade. Biofuel production costs worldwide vary significantly, and so does the production potential of different regions. It therefore appears to be substantial potential benefits from international trade in biofuels, but lacking specific rules, biofuels are generally subject to customs, duties and taxes without any particular limits. The ethanol market in several developed countries is strongly protected by high tariffs. However, we should keep in mind that ethanol itself is part of a list of environmental products for which accelerated dismantling of trade barriers is sought, so there are some prospects for the eventual elimination of such tariffs. For Tanzania and other developing countries, an initial protection of local manufacturers (e.g. through import duties) against cheaper imports is necessary if the build-up of a strong national biofuels industry is to be achieved.

We can conclude by mentioning the so called “Green OPEC”, an African organization of biofuels producing and exporting countries where some of the continent poorest nations are clubbing together to try to position themselves as global suppliers of biofuel itself.
13 nations met in Senegal to form the Pan-African Non-Petroleum Producers Association (PANPP), aimed at developing alternative energy sources, especially biofuels.
As a matter of fact, Africa produces a range of crops that could be used to make biofuel: these include sugar cane, sugar beet, maize, sorghum and cassava (suitable for ethanol production) and peanuts, jatropha and palm oil (for the production of biodiesel). Thus, turning to biofuels is considered by many as the only way out of the threat of a permanent economic regression that might hit those areas of the continent that lack crude reserves (especially in a period of soaring oil prices), achieving at once national energy supply diversification, energy security and on balance of payments thanks to the avoided costly outlays for fuel imports.


 

Towards biofuels certification

There is a growing concern regarding the need for biofuels to receive third party, independent environmental certification, as current practice of automatically classifying all biofuels as ‘renewable’ (regardless of how they are produced) is counter-productive
That is, the industry needs a proof that not only biofuels are less harmful on the environment than other traditional fuels, but also that the production process itself is environment friendly from cradle to grave, and complying with corporate environmental regulations.

Indeed, to date biofuels are facing many sustainability challenges, stemming from structural agricultural components as employment and farm income issues to chemical, fertilizer and fuel inputs impacting the overall energy balance of different biofuel products. Various dematerializations and substitutions throughout the life cycle of biofuel production and processing have been progressing, however did not always go far enough. At the regional and local level site selection and its effects on biodiversity, and local water quality, are often of significant concern.

Biofuel certification could also be of vital importance for those organizations (both private and public) willing to promote their “green” image with other stakeholders and the public at large. Indeed, consumers turn to biofuels trusting that by their choice they make a difference, contributing to the reduction of their environmental footprint related to energy use. A certification providing an assessment of biofuels value chain can be the key to ensuring that this trust is well placed.

Not only environmental concerns are related to the setting up of biofuel certification, as some fear, for instance, that this might be against WTO rules; however, most analyses on the issue (such as that of law firm DLA Piper) advise that, as long as the system is carefully designed so that it treats all market players equally and is based on thorough consultation with all concerned, it should be compatible³⁷.

Today, there are no green labels specifically tailored to biofuels and assessing their whole value chain, as the only type of certificate that exists is a guarantee for a certain percentage of biofuel content in gasoline or diesel (Sustainable biofuels program; White Paper 2006). However, there are plenty of activities going on in the context of grey energy assessment and Life Cycle Assessment (LCA) of biofuel. We can mention, for instance, the completed EU-study by the Joint Research Center (http://ies.jrc.cec.eu.int/wtw.html) as well as the ongoing SOFE project (http://www.esu-services.ch/bioenergy.htm).

Biofuels can be produced in many different ways, from a large variety of crops and feedstock. Depending on the technologies and processes used, biofuels can have a positive or negative ecological and social impact, and a labeling/certification process could provide some guidance and incentive for the increasingly growing markets to develop in a “sustainable” way.

If we broaden the perspective, we note how to date there is a wide range of initiatives and standards which, even if focusing on more “generic” issues as the sustainability of “agriculture” and “forestry”, indirectly deal with the eco-friendliness of biofuels.
As far as agriculture is concerned, we can mention for instance the Sustainable Agriculture Network (SAN), a coalition of organizations promoting the sustainability (both environmental and social) of agricultural activities by developing a standard and certifying farms complying with it.
In 2005, SAN approved the final version of the standard, whose list of principles is hereby presented as they apply to all crops, including of course those providing biofuels feedstock³⁸:

■ EMS
■ Ecosystem conservation
■ Wildlife protection
■ Water conservation
■ Fair treatment and good working conditions for workers
■ Occupational H&S
■ Community relations
■ Integrated crop management
■ Soil management and conservation
■ Integrated waste management

Also forestry management is relevant for the sustainability of biofuels, as it both provides feedstock for their production and “vital space” for fuel crops to be grown.
With forest certification an independent organization develops standards of good forest management, and then independent auditors issue certificates stating that forests are well-managed—as defined by a particular standard—and ensures that certain products like biofuel feedstock come from responsibly managed forests.
To date there are several different systems throughout the world, as no single forest management standard is universally accepted, each taking a somewhat different approach in defining standards for sustainable forest management.
Just as to provide some examples, we hereby list some common certification standards:

> Forest Stewardship Council (FSC)³⁹
> Sustainable Forestry Initiative (SFI)⁴⁰
> Programme for the Endorsement of Forest Certification schemes (PEFC)⁴¹

Some criteria for the award of the certificate to biofuel linked operations might regard, for instance, the necessity to re-forest areas whose trees have been cut down to provide biofuel industry with fresh timber.
The area of forest certified worldwide is growing rapidly. As of May 2006, there were over 270 mil ha of forest certified under the CSA, FSC, SFI and other main standards, representing around 7% of global forest area:⁴²

Unfortunately, to date most certified forestry operations are located in Europe and North America but not in other vital areas for biofuels, such as Brazil. Future policies and efforts should hence focus on these strategic regions, where the development of such certifications is hindered by the lack of capacity to undergo a certification audit and maintain operations to a certification standard suffered by most organizations.



References

> Biofuels for transportation. Global potential and implications for sustainable agriculture and energy in the 21st century
> International resource costs of biodiesel and bioethanol (UK Government, Department for Transport)
> Parlak, Biofuels: Environmental and Economical Impact of Using Renewable Energy Sources in Fossil Fuel Importing Countries
> EPA Tier I and Tier II health effects testing
> Life Cycle Inventory of Biodiesel and Petroleum Diesel for Use in an Urban Bus, 1998, Sheehan, et. al.
> Farrell et al 2006. “Ethanol Can Contribute to Energy and Environmental Goals.” Science 311: 506-508.
> National Biodiesel Board (NBB), Fact Sheets
> EPA "A Comprehensive Analysis of Biodiesel Impacts on Exhaust Emissions"
> World Resource Institute Policy note1, September 2006
> Brown, L. R., 1997, The Agricultural Link: How Environmental Deterioration Could
> Disrupt Economic Progress:Worldwatch Institute,Washington, DC
> McNeely (IUCN):Biofuels: green energy or grim reaper? 2006
> George Monbiot, “Fuel for Naught,” The Guardian (London), November 23, 2004
> SRU, Reducing CO2 emisions from cars, 2005
> Vern Hofman, Biodiesel Fuel, AE-1240, North Dakota State University, February, 2003
> Gururaja, Biofuels and sustainable development: issue, challenges and options (UNDESA/DSD)
> Pimentel and Tad W. Patzek; report available at Natural Resources Research (Vol. 14:1, 65-76)
> 12 Myths About Hunger based on World Hunger: 12 Myths, 2nd Edition, by Lappé, et al, 1998
> Food for Thought by Elliott H. Gue - The Energy Letter February 22, 2006
> Potenziali areali italiani per colture dedicate da energia, P. Venturi, G. Venturi, Rivista di ingegneria Agraria (2005)
> http://www.jatrophaworld.org/9.html
> www.heinzctr.org/ecosystems
> IEA: biofuels for transport, an international perspective, 2004
> http://en.wikipedia.org/wiki/Ethanol_fuel_in_Brazil
> EC Communication 8.2.2006, COM(2006) 34 Bruxelles
> Liquid biofuels for transportation in Tanzania, GTZ 2005
> World Energy Outlook 2006, IEA
> Potenziali areali italiani per colture dedicate da energia, P. Venturi, G. Venturi, Rivista di ingegneria Agraria (2005)
> Von Braun, Pachauri, The promises and challenges of Biofuels for the poor in developing countries. IFPRI 2006
> SAN: Sustainable Agriculture Standard, 2005
> Craxner: Forest Certification and certified forest products. 2006
> www.fsc.org
> http://www.aboutsfi.org/core.asp
> www.pefc.org
> http://www.transportenvironment.org/docs/presentations/2006/2006-06_biofuels/Lancaster_Presentation_pdf.pdf


(*)  pietro.lanzini@yahoo.com.

1 Biofuels for transportation. Global potential and implications for sustainable agriculture and energy in the 21st century.
2 International resource costs of biodiesel and bioethanol (UK Government, Department for Transport).
3 Parlak, Biofuels: Environmental and Economical Impact of Using Renewable Energy Sources in Fossil Fuel Importing Countries.
4 EPA Tier I and Tier II health effects testing.
5 Life Cycle Inventory of Biodiesel and Petroleum Diesel for Use in an Urban Bus, 1998, Sheehan, et. al.
6 Farrell, Alexander E., Richard Plevin, Brian Turner, Andrew Jones, Michael O’Hare, and Daniel Kammen. 2006. “Ethanol Can Contribute to Energy and Environmental Goals.” Science 311: 506-508.
7 National Biodiesel Board (NBB), Fact Sheets.
8 EPA "A Comprehensive Analysis of Biodiesel Impacts on Exhaust Emissions".
9 World Resource Institute Policy note1, September 2006.
10 Brown, L. R., 1997, The Agricultural Link: How Environmental Deterioration Could Disrupt Economic Progress:Worldwatch Institute,Washington, DC.
11 McNeely (IUCN):Biofuels: green energy or grim reaper? 2006.
12 George Monbiot, “Fuel for Naught,” The Guardian (London), November 23, 2004.
13 SRU, Reducing CO2 emisions from cars, 2005.
14 Vern Hofman, Biodiesel Fuel, AE-1240, North Dakota State University, February, 2003.
15 Gururaja, Biofuels and sustainable development: issue, challenges and options (UNDESA/DSD).
16 Pimentel, Ethanol Fuels: Energy Balance, Economics, and Environmental Impacts are Negative. Natural Resources Research, Vol. 12, No. 2, June 2003.
17 Pimentel and Tad W. Patzek; report available at Natural Resources Research (Vol. 14:1, 65-76).
18 12 Myths About Hunger based on World Hunger: 12 Myths, 2nd Edition, by Lappé, et al, 1998.
19 Food for Thought by Elliott H. Gue - The Energy Letter February 22, 2006.
20 Potenziali areali italiani per colture dedicate da energia, P. Venturi, G. Venturi, Rivista di ingegneria Agraria (2005).
21 http://www.jatrophaworld.org/9.html.
22 http://64.233.161.104/search?q=cache:F0C6VA4C9bAJ:www.indiamart.com/aryanmushroom/+%22ad vantages+of+Jatropha%22+biofuel&hl=it&gl=it&ct=clnk&cd=8 and www.dayafterindia.com.
23 http://64.233.161.104/search?q=cache:D5QbRT4p2hsJ:www.socialtext.net/brightgreen/index.cgi%3Fjatropha+Jatropha+disadvantages&hl=it&gl=it&ct=clnk&cd=4.
24 Trabi, G.M. Gübitz, W. Steiner, N. Foidl: Toxicity of Jatropha curcas seeds. Developed from the Symposium "Jatropha 97" Managua, Nicaragua February 23 – 27, 1997.
25 Visit www.heinzctr.org/ecosystems.
26 Data taken from the IEA: biofuels for transport, an international perspective, 2004.
27 Von Braun, Pachauri, The promises and challenges of Biofuels for the poor in developing countries. IFPRI 2006.
28 Biofuels: Green energy or grim reaper? Jeff McNeely.
29 http://en.wikipedia.org/wiki/Ethanol_fuel_in_Brazil.
30 Coelho: Brazilian sugarcane ethanol: lessons learned. 2005.
31 Economist.com “A ransom worth paying”, November 27th 2006.
32 http://en.wikipedia.org/wiki/Ethanol_fuel_in_Brazil.
33 World Energy Outlook 2006, IEA.
34 Gururaja, Biofuels and sustainable development: issue, challenges and options (UNDESA/DSD).
35 EC Communication 8.2.2006, COM(2006) 34 Bruxelles.
36 Liquid biofuels for transportation in Tanzania, GTZ 2005.
37 http://www.transportenvironment.org/docs/presentations/2006/2006-06_biofuels/Lancaster_Presentation_pdf.pdf.
38 SAN: Sustainable Agriculture Standard, 2005.
39 www.fsc.org.
40 http://www.aboutsfi.org/core.asp.
41 www.pefc.org.
42 Craxner: Forest Certification and certified forest products. 2006.

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