Refine
Year of Publication
Document Type
- Peer-Reviewed Article (33)
- Part of a Book (29)
- Report (28)
- Working Paper (12)
- Conference Object (10)
- Contribution to Periodical (7)
- Book (1)
Language
- English (120) (remove)
Concerns over climate change and the security of industrial feedstock supplies have been opening a growing market for biobased materials. This development, however, also presents a challenge to scientists, policy makers, and industry because the production of biobased materials requires land and is typically associated with adverse environmental effects. This article addresses the environmental impacts of biobased materials in a meta-analysis of 44 life cycle assessment (LCA) studies. The reviewed literature suggests that one metric ton (t) of biobased materials saves, relative to conventional materials, 55 ± 34 gigajoules of primary energy and 3 ± 1 t carbon dioxide equivalents of greenhouse gases. However, biobased materials may increase eutrophication by 5 ± 7 kilograms (kg) phosphate equivalents/t and stratospheric ozone depletion by 1.9 ± 1.8 kg nitrous oxide equivalents/t. Our findings are inconclusive with regard to acidification (savings of 2 ± 20 kg sulfur dioxide equivalents/t) and photochemical ozone formation (savings of 0.3 ± 2.4 kg ethene equivalents/t). The variability in the results of life cycle assessment studies highlights the difficulties in drawing general conclusions. Still, common to most biobased materials are impacts caused by the application of fertilizers and pesticides during industrial biomass cultivation. Additional land use impacts, such as the potential loss of biodiversity, soil carbon depletion, soil erosion, deforestation, as well as greenhouse gas emissions from indirect land use change are not quantified in this review. Clearly these impacts should be considered when evaluating the environmental performance of biobased materials.
An input-output approach to analyse the Total Material Requirement (TMR) of national economies
(1999)
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.
Assessing global resource use : a systems approach to resource efficiency and pollution reduction
(2017)
The growing demand for wood to meet EU renewable energy targets has increasingly come under scrutiny for potentially increasing EU import dependence and inducing land use change abroad, with associated impacts on the climate and biodiversity. This article builds on research accounting for levels of primary timber consumption - e.g., toward forest footprints - and developing reference values for benchmarking sustainability - e.g., toward land use targets - in order to improve systemic monitoring of timber and forest use. Specifically, it looks at future trends to assess how current EU policy may impact forests at an EU and global scale. Future demand scenarios are based on projections derived and adapted from the literature to depict developments under different scenario assumptions. Results reveal that by 2030, EU consumption levels on a per capita basis are estimated to be increasingly disproportionate compared to the rest of the world. EU consumption scenarios based on meeting around a 40% share of the EU renewable energy targets with timber would overshoot both the EU and global reference value range for sustainable supply capacities in 2030. Overall, findings support literature pointing to an increased risk of problem shifting relating to both how much and where timber needed for meeting renewable energy targets is sourced. It is argued that a sustainable level of timber consumption should be characterized by balance between supply (what the forest can provide on a sustainable basis) and demand (how much is used on a per capita basis, considering the concept of fair shares). To this end, future research should close data gaps, increase methodological robustness and address the socio-political legitimacy of the safe operating space concept towards targets in the future. A re-use of timber within the economy should be supported to increase supply options.
Consumption of natural resources should not exceed sustainable levels. The increasing use of biofuels and to some extent biomaterials, on top of rising food and feed demands, is causing countries to use a growing amount of global land, which may lead to land use conflicts and the expansion of cropland and intensive cultivation at the expense of natural ecosystems. Selective product certification cannot control the land use change triggered by growing overall biomass consumption. We propose a comprehensive approach to account for the global land use of countries for their domestic consumption, and assess this level with regard to globally acceptable levels of resource use, based on the concept of safe operating space. It is shown that the European Union currently uses one-third more cropland than globally available on a per capita basis and that with constant consumption levels it would exceed its fair share of acceptable resource use in 2030. As the use of global forests to meet renewable energy targets is becoming a concern, an approach to account for sustainable levels of timber flows is also proposed, based on the use of net annual increment, exemplified with preliminary data for Switzerland. Altogether, our approach would integrate the concept of sustainable consumption into national resource management plans; offering a conceptual basis and concrete reference values for informed policy making and urging countries to monitor and adjust their levels of resource consumption in a comprehensive way, respectful of the limits of sustainable supply.
On the one hand, biofuels may provide environmental and social benefits, for instance, when local communities in developing countries are supplied with power and process energy from oil producing plants, in particular when they are grown on land which is not suited for food production. On the other hand, the ongoing expansion of large scale energy farming for transport biofuels can lead to various environmental and social problems. Corn production for ethanol (additive to petrol) for instance resulted in nutrient pollution of the Mississippi basin and the Gulf of Mexico. The growing demand of transport biofuels in Europe can only be met by increasing imports. This contributes to the conversion of grasslands, savannahs and forests in the tropics, losses of biodiversity and additional green house gas emissions. Even if the use of biomass for other purposes, for instance, the combined production of electricity and heat usually provides a better greenhouse gas balance than transport biofuels, energy cropping remains problematic for various reasons. Whereas, when biomass is used for material purposes first, and the energy is recovered from the subsequent waste, a multiple dividend can be gained. The authors address a number of measures for improvement. They also recommend that in view of the complex circumstances of biofuel production and application, current policy mandates and targets for biofuels should be reconsidered. Biomass policies need to be integrated into a broader perspective of sustainable resource management.
Bridging the data gap
(2004)
The current flow of carbon for the production, use, and waste management of polymer-based products is still mostly linear from the lithosphere to the atmosphere with rather low rates of material recycling. In view of a limited future supply of biomass, this article outlines the options to further develop carbon recycling (C-REC). The focus is on carbon dioxide (CO2) capture and use for synthesis of platform chemicals to produce polymers. CO2 may be captured from exhaust gases after combustion or fermentation of waste in order to establish a C-REC system within the technosphere. As a long-term option, an external C-REC system can be developed by capturing atmospheric CO2. A central role may be expected from renewable methane (or synthetic natural gas), which is increasingly being used for storage and transport of energy, but may also be used for renewable carbon supply for chemistry. The energy input for the C-REC processes can come from wind and solar systems, in particular, power for the production of hydrogen, which is combined with CO2 to produce various hydrocarbons. Most of the technological components for the system already exist, and, first modules for renewable fuel and polymer production systems are underway in Germany. This article outlines how the system may further develop over the medium to long term, from a piggy-back add-on flow system toward a self-carrying recycling system, which has the potential to provide the material and energy backbone of future societies. A critical bottleneck seems to be the capacity and costs of renewable energy supply, rather than the costs of carbon capture.
As illustrated by the case studies of end-of-life vehicles and waste electric and electronic equipment, the approach of an extended producer responsibility is undermined by the exports of used and waste products. This fact causes severe deficits regarding circular flows, especially of critical raw materials such as platinum group metals. With regard to global recycling there seems to be a responsibility gap which leads somehow to open ends of waste flows and a loss or down-cycling of potential secondary resources. Existing product-orientated extended producer responsibility (EPR) approaches with mass-based recycling quotas do not create adequate incentives to supply waste materials containing precious metals to a high-quality recycling and should be amended by aspects of a material stewardship. The paper analyses incentive effects on EPR for the mentioned product groups and metals, resulting from existing regulations in Germany. It develops a proposal for an international covenant on metal recycling as a policy instrument for a governance-oriented framework to initiate systemic innovations along the complete value chain taking into account product group- and resource group-specific aspects on different spatial levels. It aims at the effective implementation of a central idea of EPR, the transition of a waste regime still focusing on safe disposal towards a sustainable management of resources for the complete lifecycle of products.
The CO2 utilisation is discussed as one of the future low-carbon technologies in order to accomplish a full decarbonisation in the energy intensive industry. CO2 is separated from the flue gas stream of power plants or industrial plants and is prepared for further processing as raw material. CO2 containing gas streams from industrial processes exhibit a higher concentration of CO2 than flue gases from power plants; consequentially, industrial CO2 sources are used as raw material for the chemical industry and for the synthesis of fuel on the output side. Additionally, fossil resources can be replaced by substitutes of reused CO2 on the input side. If set up in a right way, this step into a CO2-based circular flow economy could make a contribution to the decarbonisation of the industrial sector and according to the adjusted potential, even rudimentarily to the energy sector.
In this study, the authors analyse potential CO2 sources, the potential demand and the range of applications of CO2. In the last chapter of the final report, they give recommendations for research, development, politics and economics for an appropriate future designing of CO2 utilisation options based upon their previous analysis.
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.