2008.11.07 - Life cycle energy assessment of biofuels in Portugal
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Life cycle energy assessment of biofuels Daniel Borrego Faculty of Sciences, University of Lisbon Campo Grande, 1749-016, Lisbon, Portugal [email protected] Keywords: energy demand, energy balance, land use, GHG emissions ABSTRACT Portugal has specific environmental and farming characteristics, such as an arid climate, risk of soil erosion, high climatic variability over the year as well as a high share of extensive farmland with a high nature value. Other Mediterranean countries also face a similar situation having areas that need to be protected either from intensification and abandonment. Traditionally cultures areas, unused lands, and set-aside areas are being considered to suppress the demand of biofuels. There is a growing awareness that the impacts of the increasing demand of biofuels go beyond their emissions balance. Life cycle assessment should address the energy consumption of biofuels production but also other impacts such the impacts on biodiversity and in land use and land use change should also be considered, when evaluating the sustainability of biofuels production. Land allocation should be made in order to minimize land-use conflicts, considering the use of degraded land whenever it is possible. Irrigated land should be considered for new energy crops especially as an alternative to intensive food production. Assessment of biomass production should analyse how feedstocks grow, how they are processed into biofuels and what’s the structure ownership of refining capacity. WORLD ENERGY OVERVIEW World is facing a double challenge regarding energy usage. In the future we may not have enough energy sources at affordable prices and the environmental impacts of producing the total amount of final energy required could be dangerous. The economic and social consequences of the instable pattern of fossil fuel prices have been increasing the belief that it is no longer possible to built sustainable societies using the same energy mix used so far. However this is not only a matter of the type of energy mix but also a question of the total amount of energy demand. World energy consumption has been rising and it is not likely that it decrease. Primary energy demand increases 58% between 1984 and 2006 (IEA, 2006; IEA 2008). According the reference scenario of the International Energy Agency (EIA) it is expectable that world energy consumption, in 2030, stays 53% above 2004 values (IEAb, 2006). OCDE real gross domestic product (GDP) growth has been less than half of the developing countries (since 1990) and should stay like that until 2030. At the same time the population growth rates of developing countries has been twice as much the OCDE. These factors justify why developing countries should be the main world energy user in 2030 (IEAb, 2006), representing more than 70% of this expected increase. Fossil fuels are expected to still being the main energy source during the period 2004-2030 (Figure 1) and should slightly increase their share from 80% in 2004 to 81% in 2030. Oil nonetheless remains the single largest fuel in the primary fuel mix in 2030, though its share drops from 35% to 33% in the same period. Negative environmental consequences of fossil fuels and concerns about petroleum supplies have spurred the search for renewable transportation biofuels.
Figure 1 – World primary energy demand by fuel Source: IEAb, 2006 BIOFUEL TARGETS AND POTENCIAL CONFLICTS European targets for biofuels In 2003 the European Union (EU) adopted the biofuels directive with the goal of reduce their dependence on fossil fuels. Member States should ensure that biofuels and other renewable fuels are placed in the transport sector. These fuels should be at least 2% of the total energy content of the petrol and diesel used in transportation sector by 31 December 2005 and 5.75% by 31 December 2010. The starting point was 0.5% by 2003 (EC, 2006). By 2005 the EU share of biofuels was around 1%. Only Germany (3.8%) and Sweden (2.2%) achieved the 2% target. Germany’s success was mostly based on biodiesel while Sweden has concentrated on bioethanol. Sweden is also the European leader for biogas use in transport (EC2, 2006).
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Land use, biodiversity and deforestation One of the central conflict issues in cultivating bioenergy crops is land use, which varies depending on crop species, cultivation methods and soil and climatic condition (WWF, 2006). Species differ in biomass production and soil C storage is primarily controlled by two fundamental processes: net primary productivity (NPP) and decomposition. Increase in NPP results in an increased C storage, whereas increased decomposition has an opposite effect (Yang and Hsieh, 2002). Depending on its spatial distribution and cultivation practices, increased bioenergy cropping could result in the loss of habitats and the endangerment or extinction of rare species, obstruction of migration patterns and corridors, and degradation of soils and water bodies. On the other hand, appropriately selected and managed bioenergy cultivation could also enhance soil quality, habitats and the biodiversity of current arable land (WWF, 2006). Management of degraded areas with more perennial crops (grasses) can enhance soil quality and improve soil organic carbon sink capacity by improving plant productivity (Lemus and Lal, 2005). Maintaining plant species with good vegetation cover and deep root systems such as perennial grasses are important to increase soil organic carbon pool in deeper soil layers (Lal, 2004). However, the land-use effects of bioenergy-cropping systems must be considered with reference to current landuse (if any) to allow a complete life cycle assessment. At the production level good practices should be implemented through management plans so that farming operations ensure the protection of “high nature value” farming systems. In order to preserve genetic diversity, a minimum number of crop species and varieties, as well as structural diversity within the bioenergy cropping area must be demonstrated in management plans. ENERGY AND CARBON BALANCE While biofuels potentially offer environmental and energy security benefits, one cannot take for granted that they will. While most biofuels generally have low toxicity, meaning spills are not as problematic as conventional fuel spills (Childs and Bradley, 2007) the different feedstocks and processes involved in producing these fuels determine if their life cycle environmental impacts are less than those of petroleum-based fuels. As the leading drivers of interest in biofuels is energy security and reduced GHG emissions it is important to evaluate biofuels based on their ability to reduce fossil fuel demand. This approach cannot replace the analysis of other environmental externalities that could exist such as impacts on water, food price, and biodiversity. To be a viable substitute for a fossil fuel, an alternative fuel should provide a net energy gain over the energy sources used to produce it (Hill et al., 2006). To perform an energy balance of a biofuel it’s necessary to quantify the energy inputs verified in farm and processing. The processes included should be those identified in Table 1. Table 1 – Processes to include in the energy balance Farm Household energy use
Processing Facility energy use
Machinery production Fertilizers and pesticides Fossil fuel use Hybrid or varietal seed
Facility labourer energy use Facility construction Transportation
DISCUSSION Biofuels seek to displace oil consumption with homegrown alternative fuels, and in the process achieve several aims including mitigating climate change, improving energy security, and supporting rural incomes. To decide on the success of overall displacement the impacts of biofuels on rural incomes, land rights, deforestation including land-use impacts, distributional equity, water use, destruction of wildlife habitats, and other issues must be addressed for each specific situation. The degree of benefit or harm may depend critically on the local characteristics of production. In the case of Mediterranean countries as Portugal, their specific environmental and farming characteristics, such as an arid climate, risk of soil erosion, high climatic variability over the year as well as a high share of extensive farmland with a high nature value must be evaluated. Biofuels are not intrinsically “green”, nor are they necessarily energy-saving, pro-poor, or development oriented. There are many ways to grow feedstocks, process them into biofuels, structure ownership of refining capacity, and distribute benefits among stakeholders; these aspects of production, and not the only product’s chemical composition should determine whether biofuels will be broadly beneficial or not. REFERENCES [1] IEA, 2006, Key World Energy Statistics 2006 [2] IEAb, 2006, World Energy Outlook 2006, Paris [3] IEA, 2008, Key World Energy Statistics 2008 [4] EC (2006); An EU strategy for biofuels; European Commission, COM(2006)34 final, February [5] EC2 (2006); Biofuels Progress Report: report on the progress made in the use of biofuels and other renewable fuels in the Member States of the European Union; COM(2006) 845 final; January 2007 [6] World Wild Foundation (WWF), 2006, Sustainable standards for bioenergy [7] Yang W. and Hsieh YP. 2002. Uncertainties and novel prospects in the study of soil carbon dynamics. Chemosphere 49: 791–804. [8] Lemus R and Lal R. Bioenergy Crops and Carbon Sequestration', Critical Reviews in Plant Sciences. 2005; 24:1, 1 – 21 [9] Lal, R. 2004. Soil carbon sequestration to mitigate climate change. Geoderma. 2004; 123: 151–184. [10] Childs B. and Bradley R. 2007, Plants at the pump – biofuels, climate change and sustainability, World Resources Institute [11] Hill, J., Nelson, E., Tilman, D., Polasky, S., and Tiffany, D.: Environmental, economic, and energetic costs and benefits of biodiesel and ethanol biofuels, Proc. Nat. Acad. Sci., 103, 11 206–11 210, 2006.
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Life cycle energy assessment of biofuels Daniel Borrego Faculty of Sciences, University of Lisbon Campo Grande, 1749-016, Lisbon, Portugal [email protected] Keywords: energy demand, energy balance, land use, GHG emissions ABSTRACT Portugal has specific environmental and farming characteristics, such as an arid climate, risk of soil erosion, high climatic variability over the year as well as a high share of extensive farmland with a high nature value. Other Mediterranean countries also face a similar situation having areas that need to be protected either from intensification and abandonment. Traditionally cultures areas, unused lands, and set-aside areas are being considered to suppress the demand of biofuels. There is a growing awareness that the impacts of the increasing demand of biofuels go beyond their emissions balance. Life cycle assessment should address the energy consumption of biofuels production but also other impacts such the impacts on biodiversity and in land use and land use change should also be considered, when evaluating the sustainability of biofuels production. Land allocation should be made in order to minimize land-use conflicts, considering the use of degraded land whenever it is possible. Irrigated land should be considered for new energy crops especially as an alternative to intensive food production. Assessment of biomass production should analyse how feedstocks grow, how they are processed into biofuels and what’s the structure ownership of refining capacity. WORLD ENERGY OVERVIEW World is facing a double challenge regarding energy usage. In the future we may not have enough energy sources at affordable prices and the environmental impacts of producing the total amount of final energy required could be dangerous. The economic and social consequences of the instable pattern of fossil fuel prices have been increasing the belief that it is no longer possible to built sustainable societies using the same energy mix used so far. However this is not only a matter of the type of energy mix but also a question of the total amount of energy demand. World energy consumption has been rising and it is not likely that it decrease. Primary energy demand increases 58% between 1984 and 2006 (IEA, 2006; IEA 2008). According the reference scenario of the International Energy Agency (EIA) it is expectable that world energy consumption, in 2030, stays 53% above 2004 values (IEAb, 2006). OCDE real gross domestic product (GDP) growth has been less than half of the developing countries (since 1990) and should stay like that until 2030. At the same time the population growth rates of developing countries has been twice as much the OCDE. These factors justify why developing countries should be the main world energy user in 2030 (IEAb, 2006), representing more than 70% of this expected increase. Fossil fuels are expected to still being the main energy source during the period 2004-2030 (Figure 1) and should slightly increase their share from 80% in 2004 to 81% in 2030. Oil nonetheless remains the single largest fuel in the primary fuel mix in 2030, though its share drops from 35% to 33% in the same period. Negative environmental consequences of fossil fuels and concerns about petroleum supplies have spurred the search for renewable transportation biofuels.
Figure 1 – World primary energy demand by fuel Source: IEAb, 2006 BIOFUEL TARGETS AND POTENCIAL CONFLICTS European targets for biofuels In 2003 the European Union (EU) adopted the biofuels directive with the goal of reduce their dependence on fossil fuels. Member States should ensure that biofuels and other renewable fuels are placed in the transport sector. These fuels should be at least 2% of the total energy content of the petrol and diesel used in transportation sector by 31 December 2005 and 5.75% by 31 December 2010. The starting point was 0.5% by 2003 (EC, 2006). By 2005 the EU share of biofuels was around 1%. Only Germany (3.8%) and Sweden (2.2%) achieved the 2% target. Germany’s success was mostly based on biodiesel while Sweden has concentrated on bioethanol. Sweden is also the European leader for biogas use in transport (EC2, 2006).
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Land use, biodiversity and deforestation One of the central conflict issues in cultivating bioenergy crops is land use, which varies depending on crop species, cultivation methods and soil and climatic condition (WWF, 2006). Species differ in biomass production and soil C storage is primarily controlled by two fundamental processes: net primary productivity (NPP) and decomposition. Increase in NPP results in an increased C storage, whereas increased decomposition has an opposite effect (Yang and Hsieh, 2002). Depending on its spatial distribution and cultivation practices, increased bioenergy cropping could result in the loss of habitats and the endangerment or extinction of rare species, obstruction of migration patterns and corridors, and degradation of soils and water bodies. On the other hand, appropriately selected and managed bioenergy cultivation could also enhance soil quality, habitats and the biodiversity of current arable land (WWF, 2006). Management of degraded areas with more perennial crops (grasses) can enhance soil quality and improve soil organic carbon sink capacity by improving plant productivity (Lemus and Lal, 2005). Maintaining plant species with good vegetation cover and deep root systems such as perennial grasses are important to increase soil organic carbon pool in deeper soil layers (Lal, 2004). However, the land-use effects of bioenergy-cropping systems must be considered with reference to current landuse (if any) to allow a complete life cycle assessment. At the production level good practices should be implemented through management plans so that farming operations ensure the protection of “high nature value” farming systems. In order to preserve genetic diversity, a minimum number of crop species and varieties, as well as structural diversity within the bioenergy cropping area must be demonstrated in management plans. ENERGY AND CARBON BALANCE While biofuels potentially offer environmental and energy security benefits, one cannot take for granted that they will. While most biofuels generally have low toxicity, meaning spills are not as problematic as conventional fuel spills (Childs and Bradley, 2007) the different feedstocks and processes involved in producing these fuels determine if their life cycle environmental impacts are less than those of petroleum-based fuels. As the leading drivers of interest in biofuels is energy security and reduced GHG emissions it is important to evaluate biofuels based on their ability to reduce fossil fuel demand. This approach cannot replace the analysis of other environmental externalities that could exist such as impacts on water, food price, and biodiversity. To be a viable substitute for a fossil fuel, an alternative fuel should provide a net energy gain over the energy sources used to produce it (Hill et al., 2006). To perform an energy balance of a biofuel it’s necessary to quantify the energy inputs verified in farm and processing. The processes included should be those identified in Table 1. Table 1 – Processes to include in the energy balance Farm Household energy use
Processing Facility energy use
Machinery production Fertilizers and pesticides Fossil fuel use Hybrid or varietal seed
Facility labourer energy use Facility construction Transportation
DISCUSSION Biofuels seek to displace oil consumption with homegrown alternative fuels, and in the process achieve several aims including mitigating climate change, improving energy security, and supporting rural incomes. To decide on the success of overall displacement the impacts of biofuels on rural incomes, land rights, deforestation including land-use impacts, distributional equity, water use, destruction of wildlife habitats, and other issues must be addressed for each specific situation. The degree of benefit or harm may depend critically on the local characteristics of production. In the case of Mediterranean countries as Portugal, their specific environmental and farming characteristics, such as an arid climate, risk of soil erosion, high climatic variability over the year as well as a high share of extensive farmland with a high nature value must be evaluated. Biofuels are not intrinsically “green”, nor are they necessarily energy-saving, pro-poor, or development oriented. There are many ways to grow feedstocks, process them into biofuels, structure ownership of refining capacity, and distribute benefits among stakeholders; these aspects of production, and not the only product’s chemical composition should determine whether biofuels will be broadly beneficial or not. REFERENCES [1] IEA, 2006, Key World Energy Statistics 2006 [2] IEAb, 2006, World Energy Outlook 2006, Paris [3] IEA, 2008, Key World Energy Statistics 2008 [4] EC (2006); An EU strategy for biofuels; European Commission, COM(2006)34 final, February [5] EC2 (2006); Biofuels Progress Report: report on the progress made in the use of biofuels and other renewable fuels in the Member States of the European Union; COM(2006) 845 final; January 2007 [6] World Wild Foundation (WWF), 2006, Sustainable standards for bioenergy [7] Yang W. and Hsieh YP. 2002. Uncertainties and novel prospects in the study of soil carbon dynamics. Chemosphere 49: 791–804. [8] Lemus R and Lal R. Bioenergy Crops and Carbon Sequestration', Critical Reviews in Plant Sciences. 2005; 24:1, 1 – 21 [9] Lal, R. 2004. Soil carbon sequestration to mitigate climate change. Geoderma. 2004; 123: 151–184. [10] Childs B. and Bradley R. 2007, Plants at the pump – biofuels, climate change and sustainability, World Resources Institute [11] Hill, J., Nelson, E., Tilman, D., Polasky, S., and Tiffany, D.: Environmental, economic, and energetic costs and benefits of biodiesel and ethanol biofuels, Proc. Nat. Acad. Sci., 103, 11 206–11 210, 2006.
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