Environmental sustainability and improvement options for agribiomass chains: Straw and turnip rape

Biofuels are seen as an effective means to reduce greenhouse gas (GHG) emissions of energy production. However, the cultivation phase of agribiomass-based biofuel production in particular can cause significant GHG emissions and additional environmental problems, such as water pollution and biodiversity loss. In this study, the aim was to develop a comprehensive environmental sustainability framework for agribiomass chains. The chosen environmental impact categories (climate change, eutrophication, soil erosion, soil organic matter decline, ecotoxicity, biodiversity, use of non-renewable resources, water use, and production efficiency) were selected based on literature and the views of energy companies and interest groups. The framework was tested with two Finnish agribiomass chains: barley (Hordeum vulgare L.) straw (for combustion) and turnip rape (Brassica rapa ssp. oleifera DC.) (for biodiesel). Relevant improvement options were identified and their impact reduction potential was assessed.The GHG emissions of both selected bioenergy sources were less than those of their fossil fuel references. Critical challenges for both studied agribiomass chains currently include eutrophication, soil organic matter decline and the use of non-renewable natural resources. The indicator values could be markedly improved by the selected improvement options, of which the most important is optimal yield. Better distributions of manure and soil fertility improvement (carbon stock and pH) were identified as the most important long-term goals for improving sustainability.     

Climate consequences of low-carbon fuels: The United States Renewable Fuel Standard

A common strategy for reducing greenhouse gas (GHG) emissions from energy use is to increase the supply of low-carbon alternatives. However, increasing supply tends to lower energy prices, which encourages additional fuel consumption. This “fuel market rebound effect” can undermine climate change mitigation strategies, even to the point where efforts to reduce GHG emissions by increasing the supply of low-carbon fuels may actually result in increased GHG emissions. Here, we explore how policies that encourage the production of low-carbon fuels may result in increased GHG emissions because the resulting increase in energy use overwhelms the benefits of reduced carbon intensity. We describe how climate change mitigation strategies should follow a simple rule: a low-carbon fuel with a carbon intensity of X% that of a fossil fuel must displace at least X% of that fossil fuel to reduce overall GHG emissions. We apply this rule to the United States Renewable Fuel Standard (RFS2). We show that absent consideration of the fuel market rebound effect, RFS2 appears to reduce GHG emissions, but once the fuel market rebound effect is factored in, RFS2 actually increases GHG emissions when all fuel GHG intensity targets are met.     

Environmental life cycle assessment of lignocellulosic conversion to ethanol: A review

Bioenergy from lignocellulosic biomass offers the potential to provide a significant source of clean, low carbon and secure energy. In recent years, a number of studies have been carried out to assess the environmental performance of lignocellulosic ethanol fuel. However, the complexity of biofuel systems generates significantly different results due to the differences in input data, methodologies applied, and local geographical conditions. Moreover, much attention has been placed on assessing climate change potential and energy consumption. This study draws on 53 published life cycle assessment of the lignocellulosic ethanol. More than half of the articles reviewed focus on assessing greenhouse gas (GHG) emission or fossil energy consumption or combination of both. All studies but two reviewed conclude that there is a reduction of GHG emission when using lignocellulosic ethanol in comparison to fossil fuel reference system. However, different studies have reported different sources contributing to GHG emission: some reports majority of GHG emissions come from biomass cultivation stage; others argue significant GHG emissions from ethanol conversion process. All articles suggest a reduction of fossil consumption in all cases of ethanol fuel. Contrary results for the impact of acidification and eutrophication potential from lignocellulosic ethanol are also observed—some reports less impact in comparison to conventional gasoline whiles others report significant increase of acidification and eutrophication potential by ethanol production. Studies also show water consumption varies significantly depending on biomass types, irrigation requirement, and regional irrigation practices; with different findings on whether agricultural practices or ethanol conversion being the main sources for water consumption. Contrary findings on emissions contributing to ecotocixity and human health have also been reported with some being favourable while others not. Results from the literature also suggest strong dependency of LCA results on system boundary, functional unit, data quality and allocation methods chosen.     

Cropping bioenergy and biomaterials in marginal land: The added value of the biorefinery concept

A biorefinery is an integrated pattern of farming and conversion activities capable to provide bioenergy and biomaterials as alternative to fossil-based refineries, increasing jobs and income in rural areas. Considering the need to avoid competition with food production in arable land, non-food cropping on marginal land is being explored worldwide focusing on lignocellulosic crops (“second-generation” substrates). The viability of bioenergy and biochemicals from non-food crops in marginal land of Southern Italy was explored, using Brassica carinata as a test crop. An LCA-consistent, integrated evaluation method, named SUMMA (Sustainability multi-scale multi-method Approach) was applied for joint assessment of material, embodied energy, environmental support (emergy) and economic flows and performance. Two hypotheses were tested: (a) cropping for bioenergy (biodiesel + heat); (b) bioenergy and biomaterials within a biorefinery framework. In addition to biodiesel production from seeds, the first hypothesis assumes the conversion of residues (cake meal and straw) into heat for local industrial use, while the second one is based on a lignocellulose-to-chemicals biorefinery. Cropping for bioenergy provides a small net energy yield with no economic return. Instead, converting lignocellulosic residues to high added value biochemicals definitely improves the process performance from both energetic and economic points of view.     

Life cycle assessment of flax shives derived second generation ethanol fueled automobiles in Spain

Biofuel use seems to have certain environmental, energy and socioeconomic advantages versus fossil fuel consumption. The substitution of fossil fuels with biofuels can be a useful tool to fulfil the Spanish and European policy in relation to mitigation of greenhouse gas (GHG) emissions and increase the security in energy supply. The continuous increase in energy consumption, dependence on energy and high petroleum prices has motivated increasing support for renewable energy promotion. In Spain (the third ethanol producer in Europe in 2007), ethanol from lignocellulosic feedstocks could be one of the most valuable and interesting possibilities for renewable transportation fuels due to the limited competition with food production and high net reduction of GHG emissions. This study is focused on flax shives, obtained as an agricultural co-product from flax crops dedicated to fibre production for specialty paper pulp manufacture as lignocellulosic biomass to produce second generation ethanol involving the use of cellulosic technology. The life cycle assessment (LCA) methodology was used to evaluate the environmental impacts of the production and use in a flexi fuel vehicle (FFV) of ethanol blends (10 and 85% in volume of ethanol with gasoline) versus conventional gasoline, throughout their whole life cycle in order to highlight the main sources of these impacts. The system boundaries include cultivation, extraction, processing and final use of fuels. Mass and economic allocation were considered to determine the effect on the results of different allocation approaches.The results of the study show that the allocation methods are essential for outcomes and decision-making. Using ethanol as transportation fuel could present better environmental performance than conventional gasoline in terms of global warming and fossil fuel consumption according to mass allocation. However, environmental credits could be achieved in terms of acidification, fossil fuel consumption and human toxicity according to economic allocation. Contributions to other impact categories such as eutrophication and photochemical oxidants formation were lower for conventional gasoline regardless of the allocation procedure selected. Agricultural activities related to feedstock production are notable contributors to the environmental performance. Thus, high yielding varieties, reduction of tillage activities and reduction in fertilization should help to reduce these impacts.     

Potential of agrifood wastes in mitigation of climate change and eutrophication - Two case regions

The aim of the study was to explore the currently unexploited potential of agrifood waste and by-product biomasses for energy recovery and nutrient recycling, to mitigate climate change and eutrophication. The technical potential was assessed in two different case regions in Finland using two contrasting processing technologies, one oriented to recycle carbon and the other one to maximise replacement of fossil energy. The reduction in nutrient surplus through efficient recycling of biomass and consequent decline in fertiliser use was calculated. The reduction in GHG emissions was estimated based on the replacement of fossil energy and the diminished fertiliser manufacture. It was established that the full potential of use of the biomass to reduce GHG emissions can only be exploited in biorefineries that both produce energy and efficiently recycle nutrients. Such biorefineries have the potential to significantly mitigate climate change and prevent eutrophication. The potential reduction in GHG emissions corresponded to a third of agricultural emissions, and the reduction in fertiliser manufacture contributed with an additional fifth of that. The energy recovery corresponded to 5-10% of the fossil energy used in the regions, and the reduction in energy use for manufacture of fertilisers represented an additional 14-20% in comparison with that. The potential for nutrient recycling corresponded to 99-120% of P and 45-72% of N in the yields harvested in the regions. The choice of technology had a more pronounced impact on energy recovery, GHG emissions and C budget than on nutrient recycling.     

Climate mitigation comparison of woody biomass systems with the inclusion of land-use in the reference fossil system

While issues of land-use have been considered in many direct analyses of biomass systems, little attention has heretofore been paid to land-use in reference fossil systems. Here we address this limitation by comparing forest biomass systems to reference fossil systems with explicit consideration of land-use in both systems. We estimate and compare the time profiles of greenhouse gas (GHG) emission and cumulative radiative forcing (CRF) of woody biomass systems and reference fossil systems. A life cycle perspective is used that includes all significant elements of both systems, including GHG emissions along the full material and energy chains. We consider the growth dynamics of forests under different management regimes, as well as energy and material substitution effects of harvested biomass. We determine the annual net emissions of CO₂, N₂O and CH₄ for each system over a 240-year period, and then calculate time profiles of CRF as a proxy measurement of climate change impact. The results show greatest potential for climate change mitigation when intensive forest management is applied in the woody biomass system. This methodological framework provides a tool to help determine optimal strategies for managing forests so as to minimize climate change impacts. The inclusion of land-use in the reference system improves the accuracy of quantitative projections of climate benefits of biomass-based systems.     

Viability of CCS: A broad-based assessment for Malaysia

Climate change is fast becoming the major environmental and energy concern worldwide. There is a major dilemma between the continued reliance on fossil fuel for our energy supply and the pressing need to address the problem of greenhouse gas (GHG) emissions from combustion process. This paper reviews the potential for carbon capture and storage (CCS) as a part of the climate change mitigation strategy for the Malaysian electricity sector using a technology assessment framework. The nation's historical trend of high reliance on fossil fuel for its electricity sector makes it a prime candidate for CCS adoption. The suitability and practicality of the technology was reviewed from a broad perspective with consideration of Malaysia-specific conditions. It is apparent from this assessment that CCS has the potential to play an important role in Malaysia's climate change mitigation strategy provided that key criteria are fulfilled.     

On sustainability of bioenergy production: Integrating co-emissions from agricultural intensification

Biomass from cellulosic bioenergy crops is seen as a substantial part of future energy systems, especially if climate policy aims at stabilizing CO₂ concentration at low levels. However, among other concerns of sustainability, the large-scale use of bioenergy is controversial because it is hypothesized to increase the competition for land and therefore raise N₂O emissions from agricultural soils due to intensification. We apply a global land-use model that is suited to assess agricultural non-CO₂ GHG emissions. First, we describe how fertilization of cellulosic bioenergy crops and associated N₂O emissions are implemented in the land-use model and how future bioenergy demand is derived by an energy-economy-climate model. We then assess regional N₂O emissions from the soil due to large-scale bioenergy application, the expansion of cropland and the importance of technological change for dedicated bioenergy crops. Finally, we compare simulated N₂O emissions from the agricultural sector with CO₂ emissions from the energy sector to investigate the real contribution of bioenergy for low stabilization scenarios.As a result, we find that N₂O emissions due to energy crop production are a minor factor. Nevertheless, these co-emissions can be significant for the option of removing CO₂ from the atmosphere (by combining bioenergy use with carbon capture and storage (CCS) options) possibly needed at the end of the century for climate mitigation. Furthermore, our assessment shows that bioenergy crops will occupy large shares of available cropland and will require high rates of technological change at additional costs.     

Identifying potential environmental impacts of large-scale deployment of dedicated bioenergy crops in the UK

There is momentum, globally, to increase the use of plant biomass for the production of heat, power and liquid transport fuels. This review assesses the evidence base for potential impacts of large-scale bioenergy crop deployment principally within the UK context, but with wider implications for Europe, the USA and elsewhere. We focus on second generation, dedicated lignocellulosic crops, but where appropriate draw comparison with current first-generation oil and starch crops, often primarily grown for food.For lignocellulosic crops, positive effects on soil properties, biodiversity, energy balance, greenhouse gas (GHG) mitigation, carbon footprint and visual impact are likely, when growth is compared to arable crops. Compared to replacement of set-aside and permanent unimproved grassland, benefits are less apparent. For hydrology, strict guidelines on catchment management must be enforced to ensure detrimental effects do not occur to hydrological resources. The threat of climate change suggests that action will be required to ensure new genotypes are available with high water use efficiency and that catchment-scale management is in place to secure these resources in future. In general, for environmental impacts, less is known about the consequences of large-scale deployment of the C4 grass Miscanthus, compared to short rotation coppice (SRC) willow and poplar, including effects on biodiversity and hydrology and this requires further research.Detailed consideration of GHG mitigation and energy balance for both crop growth and utilization suggest that perennial crops are favoured over annual crops, where energy balances may be poor. Similarly, crops for heat and power generation, especially combined heat and power (CHP), are favoured over the production of liquid biofuels. However, it is recognized that in contrast to heat and power, few alternatives exist for liquid transportation fuels at present and research to improve the efficiency and energy balance of liquid transport fuel production from lignocellulosic sources is a high current priority.Although SRC, and to a lesser extent energy grasses such as Miscanthus, may offer significant benefits for the environment, this potential will only be realized if landscape-scale issues are effectively managed and the whole chain of crop growth and utilization is placed within a regulatory framework where sustainability is a central driver. Land resource in the UK and throughout Europe will limit the contribution that crops can make to biofuel and other renewable targets, providing a strong driver to consider sustainability in a global context.     

Life cycle assessment of electricity generation using fast pyrolysis bio-oil

Biomass is expected to become an important energy source in U.S. electricity generation under state-lead renewable portfolio standards. This paper investigated the greenhouse gas (GHG) emissions for energy generated from forest resources through pyrolysis-based processing. The GHG emissions of producing pyrolysis bio-oil (pyrolysis oil) from different forest resources were first investigated; logging residues collected from natural regeneration mixed hardwood stands, hybrid poplar cultivated and harvested from abandoned agricultural lands, short rotation forestry (SRF) willow plantations and waste wood available at the site of the pyrolysis plant. Effects of biomass transportation were investigated through a range of distances to a central pyrolysis facility through road transport by semi-truck. Pyrolysis oil is assumed to be converted to electrical power through co-combustion in conventional fossil fuels power plants, gas turbine combined cycle (GTCC) and diesel generators. Life cycle GHG emissions were compared with power generated using fossil fuels and power generated using biomass direct combustion in a conventional Rankine power plant. Life cycle GHG savings of 77%–99% were estimated for power generation from pyrolysis oil combustion relative to fossil fuels combustion, depending on the biomass feedstock and combustion technologies used. Several scenario analyses were conducted to determine effects of pyrolysis oil transportation distance, N-fertilizer inputs to energy crop plantations, and assumed electricity mixes for pyrolysis oil production.     

Crop residues: applications of lignocellulosic biomass in the context of a biorefinery

Interest in lignocellulosic biomass conversion technologies has increased recently because of their potential to reduce the dependency on non-renewable feedstocks. Residues from a variety of crops are the major source of lignocellulose, which is being produced in increasingly large quantities worldwide. The commercial exploitation of crop residues as feedstocks for biorefineries which could be used to produce a variety of goods such as biofuels, biochemicals, bioplastics, and enzymes is an attractive approach not only for adding value to residues but also for providing renewable products required by the expanding bioeconomy market. Moreover, the implementation of biorefineries in different regions has the potential to add value to the specific crop residues produced in the region. In this review, several aspects of crop residue application in biorefineries are discussed, including the role of crop residues in the bioeconomy and circular economy concepts, the main technical aspects of crop residue conversion in biorefineries, the main crop residues generated in different regions of the world and their availability, the potential value-added bioproducts that can be extracted or produced from each crop residue, and the major advantages and challenges associated with crop residue utilization in biorefineries. Despite their potential, most biomass refining technologies are not sufficiently advanced or financially viable. Several technical obstacles, especially with regard to crop residue collection, handling, and pre-treatment, prevent the implementation of biorefineries on a commercial scale. Further research is needed to resolve these scale-up-related challenges. Increased governmental incentives and bioeconomic strategies are expected to boost the biorefinery market and the cost competitiveness of biorefinery products.     

A review of agricultural crop residue supply in Canada for cellulosic ethanol production

This paper estimates the availability of agricultural crop residue feedstocks in Canada for cellulosic ethanol production. Canada's major field crops generate 100.6 million dry mega grams (Mg) of crops per year while non-forage crops produce 67 million dry Mg, leaving abundant agricultural residues for use as second generation feedstock for cellulosic ethanol production. This study used crop production and livestock data from Statistics Canada for a 10-year period (2001–2010), as well as tillage data from Statistics Canada census years 2001 and 2006, to estimate crop residue availability by province and soil zone. Total residue yield from crops is calculated by incorporating straw to grain ratios. Total agricultural residues available for ethanol production are computed by deducting soil conservation and livestock uses. An average of 48 million dry Mg of agricultural residues is available per year, with a minimum of 24.5 million dry Mg in drought year 2002. This implies an average yearly potential ethanol production of 13 billion litres from crop residues over the 2001–2010 period, with a minimum of 6.6 billion litres in 2002. Ontario, Manitoba, Saskatchewan, and Quebec have enough agricultural residue supply to set up ethanol plants using agricultural crop residues as primary lignocellulosic feedstocks. There is great variability in agricultural residue production between the provinces and by soil zone. Understanding variability in feedstock supply is important for the economics and operational planning of a cellulosic ethanol biorefinery. Factors such as residue yield per hectare and soil zone will influence cellulosic ethanol plant establishment in order to exploit the abundance of lignocellulosic biomass for an ethanol plant.     

Field trial results of straw yield with different harvesting methods,and modelled effects on soil organic carbon. A case study from Southern Finland

We estimated the effects of different cutting heights and harvesting strategies on the amounts of harvestable residue biomasses and allocation of residue biomasses in the soil. A case study on regional straw biomass resources was performed with the different crops cultivated in Varsinais-Suomi (Southern Finland) at present (averages of 2003–2012) and in the predicted future warmer climate (scenario RCP 4.5, year 2055). We also estimated, with the help of the Yasso07 model, the effects of different residue incorporation intensities on soil organic carbon (SOC) at present and in the future warmer climate. The results suggested that cutting height has a significant impact on the amount of straw biomass incorporated in the soil and subsequent change in SOC. The impact depended on crop species and variety. When straw is collected and used e.g. in energy production, harvesting practices leaving greater stubble heights could help to maintain soil fertility. The Yasso07 model suggests that in the predicted future warmer conditions, more straw could be collected without decreasing SOC, as mineralization of SOC in the warmer climate is expected to increase less than organic carbon amendments caused by higher crop and root biomasses. Collection and usage of straw as a renewable energy source always decreases greenhouse gas (GHG) emissions in comparison to fossil fuels. However, collecting straw every second year instead of every year, even with higher stubble, would decrease field traffic and spare the soil from compaction and the farmer from extra work, while still significantly decreasing GHG emissions.     

Biofuels from microalgae—A review of technologies for production,processing, and extractions of biofuels and co-products

Sustainability is a key principle in natural resource management, and it involves operational efficiency, minimisation of environmental impact and socio-economic considerations; all of which are interdependent. It has become increasingly obvious that continued reliance on fossil fuel energy resources is unsustainable, owing to both depleting world reserves and the green house gas emissions associated with their use. Therefore, there are vigorous research initiatives aimed at developing alternative renewable and potentially carbon neutral solid, liquid and gaseous biofuels as alternative energy resources. However, alternate energy resources akin to first generation biofuels derived from terrestrial crops such as sugarcane, sugar beet, maize and rapeseed place an enormous strain on world food markets, contribute to water shortages and precipitate the destruction of the world's forests. Second generation biofuels derived from lignocellulosic agriculture and forest residues and from non-food crop feedstocks address some of the above problems; however there is concern over competing land use or required land use changes. Therefore, based on current knowledge and technology projections, third generation biofuels specifically derived from microalgae are considered to be a technically viable alternative energy resource that is devoid of the major drawbacks associated with first and second generation biofuels. Microalgae are photosynthetic microorganisms with simple growing requirements (light, sugars, CO₂, N, P, and K) that can produce lipids, proteins and carbohydrates in large amounts over short periods of time. These products can be processed into both biofuels and valuable co-products.This study reviewed the technologies underpinning microalgae-to-biofuels systems, focusing on the biomass production, harvesting, conversion technologies, and the extraction of useful co-products. It also reviewed the synergistic coupling of microalgae propagation with carbon sequestration and wastewater treatment potential for mitigation of environmental impacts associated with energy conversion and utilisation. It was found that, whereas there are outstanding issues related to photosynthetic efficiencies and biomass output, microalgae-derived biofuels could progressively substitute a significant proportion of the fossil fuels required to meet the growing energy demand.     

Comparative analysis of environmental impacts of maize-biogas and photovoltaics on a land use basis

This study aims to stimulate the discussion on how to optimize a sustainable energy mix from an environmental perspective and how to apply existing renewable energy sources in the most efficient way. Ground-mounted photovoltaics (PV) and the maize-biogas-electricity route are compared with regard to their potential to mitigate environmental pressure, assuming that a given agricultural area is available for energy production. Existing life cycle assessment (LCA) studies are taken as a basis to analyse environmental impacts of those technologies in relation to conventional technology for power and heat generation. The life-cycle-wide mitigation potential per area used is calculated for the impact categories non-renewable energy input, green house gas (GHG) emissions, acidification and eutrophication. The environmental performance of each system depends on the scenario that is assumed for end energy use (electricity and heat supply have been contemplated). In all scenarios under consideration, PV turns out to be superior to biogas in almost all studied impact categories. Even when maize is used for electricity production in connection with very efficient heat usage, and reduced PV performance is assumed to account for intermittence, PV can still mitigate about four times the amount of green house gas emissions and non-renewable energy input compared to maize-biogas. Soil erosion, which can be entirely avoided with PV, exceeds soil renewal rates roughly 20-fold on maize fields. Regarding the overall Eco-indicator 99 (H) score under most favourable assumptions for the maize-biogas route, PV has still a more than 100% higher potential to mitigate environmental burden. At present, the key advantages of biogas are its price and its availability without intermittence. In the long run, and with respect to more efficient land use, biogas might preferably be produced from organic waste or manure, whereas PV should be integrated into buildings and infrastructures.     

Current scenario of biodiesel development in India: prospects and challenges

For a developing nation like India, the current energy portfolio is dominated by fossil fuels such as oil, coal, and petroleum products. Due to the rapid depletion and limited available resources, the price of fossil fuel increases. Also, fossil fuel induces climate change, environmental pollution, and rising global temperature. There is urgent need to shift from conventional energy to renewable energy source for sustainable and economic growth and to enhance a country’s energy security. Biofuel offers an attractive source of energy for the substitution of fossil fuels, and looking at the huge demand for diesel in all sectors of the economy, the biodiesel is being viewed as the best substitute for diesel. The other advantage for biofuel promotion in India is climate change mitigation through reduced greenhouse gas (GHG) emission. This article provides the current status of biodiesel development in India and discusses the role played by the centre and state government in promoting second-generation feedstock (nonedible seeds) and third-generation feedstock (algae) for biodiesel production.     

Well-to-Wheels analysis of hydrogen production from bio-oil reforming for use in internal combustion engines

The environmental profile of hydrogen depends greatly on the nature of the feedstock and the production process. In this Well-to-Wheels (WTW) study, the environmental impacts of hydrogen production from lignocellulosic biomass via pyrolysis and subsequent steam reforming of bio-oil were evaluated and compared to the conventional production of hydrogen from natural gas steam reforming. Hydrogen was assumed to be used as transportation fuel in an internal combustion engine vehicle. Two scenarios for the provision of lignocellulosic biomass were considered: wood waste and dedicated willow cultivation. The WTW analysis showed that the production of bio-hydrogen consumes less fossil energy in the total lifecycle, mainly due to the renewable nature of the fuel that results in zero energy consumption in the combustion step. The total (fossil and renewable) energy demand is however higher compared to fossil hydrogen, due to the higher process energy demands and methanol used to stabilize bio-oil. Improvements could occur if these are sourced from renewable energy sources. The overall benefit of using a CO₂ neutral renewable feedstock for the production of hydrogen is unquestionable. In terms of global warming, production of hydrogen from biomass through pyrolysis and reforming results in major GHG emissions, ranging from 40% to 50%, depending on the biomass source. The use of cultivated biomass aggravates the GHG emissions balance, mainly due to the N₂O emissions at the cultivation step.     

Fossil energy and GHG saving potentials of pig farming in the EU

In Europe, the highly developed livestock industry places a high burden on resource use and environmental quality. This paper examines pig meat production in North-West Europe as a base case and runs different scenarios to investigate how improvements in terms of energy and greenhouse gas (GHG) savings can be feasibly achieved. As shown in the results of the analysis, pig farming in the EU has a high potential to reduce fossil energy use and GHG emissions by taking improvement measures in three aspects: (i) feed use; (ii) manure management; and (iii) manure utilization. In particular, a combination of improvements in all mentioned aspects offers the highest savings potential of up to 61% fossil energy and 49% GHG emissions. In weighing these three aspects, manure utilization for energy production is found to be the most important factor in reducing fossil energy use and GHG emissions. However, when GHG implications of land use change and land opportunity cost associated with the production of feed crops (e.g. soy meal, cereals) are considered, reducing feed use becomes the main factor in improving GHG performance of EU pork.