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The enhanced use of biomass for the production of energy, fuels, and materials is one of the key strategies towards sustainable production and consumption. Various life cycle assessment (LCA) studies demonstrate the great potential of bio-based products to reduce both the consumption of non-renewable energy resources and greenhouse gas emissions. However, the production of biomass requires agricultural land and is often associated with adverse environmental effects such as eutrophication of surface and ground water. Decision making in favor of or against bio-based and conventional fossil product alternatives therefore often requires weighing of environmental impacts. In this article, we apply distance-to-target weighing methodology to aggregate LCA results obtained in four different environmental impact categories (i.e., non-renewable energy consumption, global warming potential, eutrophication potential, and acidification potential) to one environmental index. We include 45 bio- and fossil-based product pairs in our analysis, which we conduct for Germany. The resulting environmental indices for all product pairs analyzed range from -19.7 to +0.2 with negative values indicating overall environmental benefits of bio-based products. Except for three options of packaging materials made from wheat and cornstarch, all bio-based products (including energy, fuels, and materials) score better than their fossil counterparts. Comparing the median values for the three options of biomass utilization reveals that bio-energy (-1.2) and bio-materials (-1.0) offer significantly higher environmental benefits than bio-fuels (-0.3). The results of this study reflect, however, subjective value judgments due to the weighing methodology applied. Given the uncertainties and controversies associated not only with distance-to-target methodologies in particular but also with weighing approaches in general, the authors strongly recommend using weighing for decision finding only as a supplementary tool separately from standardized LCA methodology.
Der vorliegende Artikel vergleicht die Nutzung nachwachsender Rohstoffe zur Erzeugung von Energie (Wärme und Elektrizität), Kraftstoffen und Gebrauchsprodukten anhand von vier ausgewählten Umweltbelastungskategorien. Dazu wurden Ökobilanzdaten aus 11 verschiedenen Publikationen für insgesamt 45 Produktpaare auf Basis nachwachsender und fossiler Rohstoffe analysiert und bezogen auf Einwohneräquivalente pro Hektar landwirtschaftliche Fläche miteinander verglichen. Die Ergebnisse zeigen im Allgemeinen Vorteile für die nachwachsenden Produktalternativen in den Kategorien Nichterneuerbarer Energieverbrauch und Treibhauspotenzial, während Produkte aus fossilen Ausgangsstoffen beim Eutrophierungspotenzial günstiger abschneiden und sich in der Kategorie Versauerungspotenzial uneinheitliche Resultate ergeben. Durch die Nutzung nachwachsender Rohstoffe zur Erzeugung von Gebrauchsgütern und Energie lassen sich durch Substitution der fossilen Produktalternativen größere ökologische Entlastungen realisieren als durch die Herstellung von Biokraftstoffen, die als Vollsubstitute für Diesel eingesetzt werden. Wesentliche Nachteile der Biomassenutzung sind mit dem Pflanzenanbau im Rahmen der konventionellen Landwirtschaft verbunden. Durch andere Bewirtschaftungsformen (z. B. Extensivierung) und eine besser an die jeweiligen Verwendungszwecke angepasste Auswahl bzw. Verarbeitung der nachwachsenden Rohstoffe könnten die Umweltbelastungen durch Energie, Kraftstoffe und Gebrauchsprodukte aus nachwachsenden Rohstoffen deutlich verringert werden.
World primary copper production is expected to increase due to growing demand. Reflecting the geographical divergence of copper deposits and demanding industries, copper is produced by various production paths, differing in regional and technological aspects and related environmental pressures. For the mitigation of environmental pressures related to global material flows and a more sustainable resource management, policy makers, producers and buyers require information on regional resource efficiencies and effects of the key processes within the global production chain. This study quantifies material flows of refined copper production and environmental pressures along the pyro‐ and hydrometallurgical paths for Chile and Germany. Inventories for involved unit processes are distinguished by region and most commonly applied technologies, including electric power supply. Different production paths are compared by environmental pressure indicators (primary energy requirements, total material requirements, water consumption, GHG emissions, solid waste disposal, sulphur dioxide and arsenic emissions). Alternative options for improvement of technologies and supply patterns in Chile and Germany are compared.
Overviewing the European carbon (C), greenhouse gas (GHG), and non-GHG fluxes, gross primary productivity (GPP) is about 9.3 Pg yr-1, and fossil fuel imports are 1.6 Pg yr-1. GPP is about 1.25% of solar radiation, containing about 360 × 1018 J energy - five times the energy content of annual fossil fuel use. Net primary production (NPP) is 50%, terrestrial net biome productivity, NBP, 3%, and the net GHG balance, NGB, 0.3% of GPP. Human harvest uses 20% of NPP or 10% of GPP, or alternatively 1‰ of solar radiation after accounting for the inherent cost of agriculture and forestry, for production of pesticides and fertilizer, the return of organic fertilizer, and for the C equivalent cost of GHG emissions. C equivalents are defined on a global warming potential with a 100-year time horizon. The equivalent of about 2.4% of the mineral fertilizer input is emitted as N2O. Agricultural emissions to the atmosphere are about 40% of total methane, 60% of total NO-N, 70% of total N2O-N, and 95% of total NH3-N emissions of Europe. European soils are a net C sink (114 Tg yr−1), but considering the emissions of GHGs, soils are a source of about 26 Tg CO2 C-equivalent yr-1. Forest, grassland and sediment C sinks are offset by GHG emissions from croplands, peatlands and inland waters. Non-GHGs (NH3, NOx) interact significantly with the GHG and the C cycle through ammonium nitrate aerosols and dry deposition. Wet deposition of nitrogen (N) supports about 50% of forest timber growth. Land use change is regionally important. The absolute flux values total about 50 Tg C yr-1. Nevertheless, for the European trace-gas balance, land-use intensity is more important than land-use change. This study shows that emissions of GHGs and non-GHGs significantly distort the C cycle and eliminate apparent C sinks.
In this article, we analyze flows of the platinum group metals (PGMs) platinum, palladium, and rhodium and the environmental impacts associated with their supply in Europe. A model of the use of PGMs in Europe has been developed, and this is combined with a model of environmental pressures related to PGM production. Seven industrial sectors and product groups form the main users of PGMs in Europe, comprising the chemical, petroleum, and glass industries; jewelry, dentistry, electronic equipment, and car catalysts. Most relevant environmental impacts of secondary production in Europe and primary PGM production in South Africa, Russia, and Canada are taken into account, including emissions of sulphur dioxide and carbon dioxide and total material requirement. The article quantifies the PGM flows to, from, and within Europe in 2004. The automotive industry is the single largest user of primary PGMs, and catalytic converters represent the major PGM end use. The chemical and glass industries also require large amounts of PGM but rely mostly on secondary metals. The environmental impacts of primary production exceed those of secondary production by far. An analysis of the use of car catalytic converters shows that as a result of efforts to reduce air pollutant emissions in Europe, other negative environmental impacts, such as point-source pollution and mining waste, are occurring elsewhere - for example, at extraction and refining sites in Siberia and South Africa.
A model of the use of the platinum group metals (PGMs) platinum, palladium, and rhodium in Europe has been developed and combined with a model of the environmental pressures related to PGM production. Compared to the base case presented in Part I of this pair of articles, potential changes in PGM production and use are quantified with regard to cumulative and yearly environmental impacts and PGM resource use, for the period 2005–2020. Reducing sulfur dioxide (SO2) emissions of PGM producer Norilsk Nickel could cut the cumulative SO2 emissions associated with the use of PGMs in Europe by 35%. Cleaner electricity generation in South Africa could reduce cumulative SO2 emissions by another 9%. Increasing the recycling rate of end-of-life catalytic converters to 70% in 2020 could save 15% of the cumulative primary PGM input into car catalysts and 10% of the SO2 emissions associated with PGM production. In 2020, PGM requirements and SO2 emissions would be, respectively, 40% and 22% lower than the base case. Substituting palladium for part of the platinum in diesel catalysts, coupled with a probable palladium price increase, could imply 15% more cumulative SO2 emissions if recycling rates do not increase. A future large-scale introduction of fuel cell vehicles would require technological improvements to significantly reduce the PGM content of the fuel cell stack. The basic design of such vehicles greatly influences the vehicle power, a key parameter in determining the total PGM requirement.
The contribution of the EU bioeconomy to sustainable development depends on how it is implemented. A high innovation potential is accompanied by considerable risks, in particular regarding the exacerbation of global land use conflicts. This article argues that a systemic monitoring system capable of connecting human-environment interactions and multiple scales of analysis in a dynamic way is needed to ensure that the EU bioeconomy transition meets overarching goals, like the Sustainable Development Goals. The monitoring should be centered around a dashboard of key indicators and targets covering environmental, economic, and social aspects of the bioeconomy. With a focus on the land dimension, this article examines the strengths and weakness of different economic, environmental and integrated models and methods for monitoring and forecasting the development of the EU bioeconomy. The state of research on key indicators and targets, as well as research needs to integrate these aspects into existing modeling approaches, are assessed. The article concludes with key criteria for a systemic bioeconomy monitoring system.
The growing demand for timber, in particular for renewable energy, increases pressures on global forests and requires a robust monitoring system to ensure sustainability. This article takes a first step toward more systemic monitoring by asking how the global use of forests by EU consumers can be accounted for. Specifically, this article builds on and develops the method of global land use accounting to account for the EU-27's consumption of primary timber between 2002 and 2011 in terms of both volume and forest area. It assesses international trade flows for around 100 commodities and converts them into a volume of primary raw timber based on conversion values. Results reveal that both imports and exports increased over the assessed time period, with primary EU-27 timber estimated to be around 1 m3/cap in 2011. Gaps, uncertainty and a lack of harmonization regarding especially trade data and conversion values are key challenges to further improving the robustness of the method and reliability of results. Future research may focus on improving the method to address in particular recycled and recovered flows as well as the question of whether area or volume is the most appropriate metric for further development of a forest footprint indicator.
Biodiversity loss is widely recognized as a serious global environmental change process. While large-scale metal mining activities do not belong to the top drivers of such change, these operations exert or may intensify pressures on biodiversity by adversely changing habitats, directly and indirectly, at local and regional scales. So far, analyses of global spatial dynamics of mining and its burden on biodiversity focused on the overlap between mines and protected areas or areas of high value for conservation. However, it is less clear how operating metal mines are globally exerting pressure on zones of different biodiversity richness; a similar gap exists for unmined but known mineral deposits. By using vascular plants' diversity as a proxy to quantify overall biodiversity, this study provides a first examination of the global spatial distribution of mines and deposits for five key metals across different biodiversity zones. The results indicate that mines and deposits are not randomly distributed, but concentrated within intermediate and high diversity zones, especially bauxite and silver. In contrast, iron, gold, and copper mines and deposits are closer to a more proportional distribution while showing a high concentration in the intermediate biodiversity zone. Considering the five metals together, 63% and 61% of available mines and deposits, respectively, are located in intermediate diversity zones, comprising 52% of the global land terrestrial surface. 23% of mines and 20% of ore deposits are located in areas of high plant diversity, covering 17% of the land. 13% of mines and 19% of deposits are in areas of low plant diversity, comprising 31% of the land surface. Thus, there seems to be potential for opening new mines in areas of low biodiversity in the future.
The amount of land directly disturbed by mining is a key generic environmental pressure indicator. A novel method based on the measurement of the cumulative net area disturbances using Landsat satellite images and its correlation with the cumulative ore production at the mine site was applied. Weighted disturbance rates (WDRs) were calculated indicating the annual quantity of hectares newly disturbed per million metric tons of ore extracted. Results show that open pit (OP) have a smaller average WDR (5.05 ha/Mt) than underground (UG) mines (11.85 ha/Mt). This is explained by the relation between the annual amounts of new net area disturbed and of ore extracted which is larger for UG than for OP mines due to the annual extraction volume (lower for UG). Overall findings demonstrate that bauxite mining has the highest WDR (7.98 ha/Mt), followed by gold (6.70 ha/Mt), silver (5.53 ha/Mt), copper (4.5 ha/Mt) and iron (4.25 ha/Mt).
Material flows induced by national economies can be regarded as indirect pressure indicators for environmental degradation. Economy-wide material flow analysis and indicators have been designed to monitor material and energy flows at the macroeconomic level and to provide indicators, which could contribute to management of resourceuse and output emission flows from both economic, environmental and broader sustainability points of view. These indicators can serve various purposes including monitoring the material basis of national economies and related environmental pressures, assessment of the material and resource productivity and monitoring the implications of trade and globalisation.
The main part of this paper compares the material and resourceuse of the Czech Republic, Germany and the EU-15 by means of DMI and TMR indicators over the period of 1991–2004 (1991–2000 for EU-15). At the aggregate level both indicators in all three economies do not show any clear decreasing or increasing trends over the period considered. This means that environmental pressure related to use of materials for production and consumption purposes remains rather stable. All the economies however, recorded an increase in the efficiency of transforming the material/resource inputs into economic output. The analysis further revealed that most of the dynamics of DMI and TMR in the Czech Republic tended towards a higher similarity with Germany and the EU-15. In the future, further decreases in DMI as well as in TMR of fossils fuels might be expected in the Czech Republic, which could be counteracted by increase in DMI and TMR of metal ores/metal resources and non-metallic minerals/non-metallic resources. The future development of total DMI, TMR and material/resource intensity in both the Czech Republic and Germany will depend on further shifts to less material intensive industries and services and on increasing material efficiency in production and consumption of particular products. This is not only a technological, but also a social challenge, as there are barriers in current mode of governance and in shaping of current economic and social systems to do so.
Previous studies showed that using carbon dioxide (CO2) as a raw material for chemical syntheses may provide an opportunity for achieving greenhouse gas (GHG) savings and a low-carbon economy. Nevertheless, it is not clear whether carbon capture and utilization benefits the environment in terms of resource efficiency. We analyzed the production of methane, methanol, and synthesis gas as basic chemicals and derived polyoxymethylene, polyethylene, and polypropylene as polymers by calculating the output-oriented indicator global warming impact (GWI) and the resource-based indicators raw material input (RMI) and total material requirement (TMR) on a cradle-to-gate basis. As carbon source, we analyzed the capturing of CO2 from air, raw biogas, cement plants, lignite-fired power, and municipal waste incineration plants. Wind power serves as an energy source for hydrogen production. Our data were derived from both industrial processes and process simulations. The results demonstrate that the analyzed CO2-based process chains reduce the amount of GHG emissions in comparison to the conventional ones. At the same time, the CO2-based process chains require an increased amount of (abiotic) resources. This trade-off between decreased GHG emissions and increased resource use is assessed. The decision about whether or not to recycle CO2 into hydrocarbons depends largely on the source and amount of energy used to produce hydrogen.
In the future, the capacities of renewable SNG (synthetic natural gas) will expand significantly. Pilot plants are underway to use surplus renewable power, mainly from wind, for electrolysis and the production of hydrogen, which is methanated and fed into the existing gas pipeline grid. Pilot projects aim at the energetic use of SNG for households and transport in particular for gas fueled cars. Another option could be the use of SNG as feedstock in chemical industry.
The early stage of development raises the question of whether SNG should be better used for mobility or the production of chemicals. This study compares the global warming potential (GWP) of the production of fossil natural gas (NG) and carbon-dioxide (CO2)-based SNG and its use for car transport versus chemical use in the form of synthesis gas. Since the potential of wind energy for SNG production is mainly located in northern Germany, the consequences by a growing distance between production in the North and transport to the South of Germany are also examined.
The results indicate that CO2-based SNG produced with wind power would lead to lower GWP when substituting NG for both uses in either transport or chemical production. Differences of the savings potential occur in short-distance pipeline transport. The critical factor is the energy required for compression along the process chain.
Poor sustainability and increasing economic shortcomings in fossil raw material use besides further technical developments of substitutes lead to a growing potential for CO2-utilisation. Hence, we balanced CO2-based methane and methanol production in a life cycle assessment and identified CO2-utilisation as a greenhouse gas saving method. However, it requires a lot of renewable energy.
Comparative analysis of environmental impacts of maize-biogas and photovoltaics on a land use basis
(2010)
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 abasis 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.
This contribution presents the state of the art of economy-wide material flow accounting. Starting from a brief recollection of the intellectual and policy history of this approach, we outline system definition, key methodological assumptions, and derived indicators. The next section makes an effort to establish data reliability and uncertainty for a number of existing multinational (European and global) material flow accounting (MFA) data compilations and discusses sources of inconsistencies and variations for some indicators and trends. The results show that the methodology has reached a certain maturity: Coefficients of variation between databases lie in the range of 10% to 20%, and correlations between databases across countries amount to an average R2 of 0.95. After discussing some of the research frontiers for further methodological development, we conclude that the material flow accounting framework and the data generated have reached a maturity that warrants material flow indicators to complement traditional economic and demographic information in providing a sound basis for discussing national and international policies for sustainable resource use.
Resource flows constitute the materials basis of the economy. At the same time, they carry and induce an environmental burden associated with resource extraction and the subsequent material flows and stocks, which finally end up as waste and emissions. A reduction of this material throughput and the related impacts would require a reduction of resource inputs. And breaking the link between resource consumption and economicgrowth would require an increase in resource productivity. Material flow analysis (MFA) can be used to quantify resource flows and indicate resource productivity. In this article, we study the available empirical evidence on the actual (de-)linkage of material resource use and economic growth. We compare resource use with respect to total material requirement (TMR) and direct material input (DMI) for 11 and 26 countries, respectively, and the European Union (EU-15). The dynamics of TMR, as well as of the main components are analysed in relation to economic growth in order to show whether there is a decoupling (relative or absolute) from GDP and a change of the metabolic structure in the course of economicdevelopment. DMI/cap so far only decoupled from GDP/cap in relative terms; that is, in most countries, it reached a rather constant level but - with the exception of Czech Republic - showed no absolute decline yet. TMR/cap was reduced in two high-income countries and one low-income country due to political influence. Changes in TMR were more influenced by hidden flows (HF) than by DMI. We analyse the dynamics of the structure and composition of TMR in the course of economic development. In general, the economic development of industrial countries was accompanied by a shift from domestic to foreign resource extraction. Different relations can be discovered for the share of biomass, fossil fuel resources, construction resources and metals and industrial minerals.
Rationale for and interpretation of economy-wide materials flow analysis and derived indicators
(2003)
Economy-wide material flow analysis (MFA) and derived indicators have been developed to monitor and assess the metabolic performance of economies, that is, with respect to the internal economic flows and the exchange of materials with the environment and with other economies. Indicators such as direct material input (DMI) and direct material consumption (DMC) measure material use related to either production or consumption. Domestic hidden flows (HF) account for unused domestic extraction, and foreign HF represent the upstream primary resource requirements of the imports. DMI and domestic and foreign HF account for the total material requirement (TMR) of an economy. Subtracting the exports and their HF provides the total material consumption (TMC). DMI and TMR are used to measure the (de-) coupling of resource use and economic growth, providing the basis for resource efficiency indicators. Accounting for TMR allows detection of shifts from domestic to foreign resource requirements. Net addition to stock (NAS) measures the physical growth of an economy. It indicates the distance from flow equilibrium of inputs and outputs that may be regarded as a necessary condition of a sustainable mature metabolism. We discuss the extent to which MFA-based indicators can also be used to assess the environmental performance. For that purpose we consider different impacts of material flows, and different scales and perspectives of the analysis, and distinguish between turnover-based indicators of generic environmental pressure and impact-based indicators of specific environmental pressure. Indicators such as TMR and TMC are regarded as generic pressure indicators that may not be used to indicate specific environmental impacts. The TMR of industrial countries is discussed with respect to the question of whether volume and composition may be regarded as unsustainable.
The global land area required to meet the German consumption of agricultural products for food and non-food use was quantified, and the related greenhouse gas (GHG) emissions, particularly those induced by land-use changes in tropical countries, were estimated. Two comprehensive business-as-usual scenarios describe the development corridor of biomass for non-food use in terms of energetic and non-energetic purposes. In terms of land use, Germany was already a net importer of agricultural land in 2004, and the net additional land required by 2030 is estimated to comprise 2.5–3.4 Mha. This is mainly due to biofuel demand driven by current policy targets. Meeting the required biodiesel import demand would result in an additional GWP of 23–37 Tg of CO2 equivalents through direct and indirect land-use changes. Alternative scenario elements outline the potential options for reducing Germany's land requirement, which reflect future global per capita availability.