Tons Of CO2 Equivalents Research Articles

An Environmental and Economic Evaluation of Pyrolysis for Energy Generation in Taiwan with Endogenous Land Greenhouse Gases Emissions

Taiwan suffers from energy insecurity and the threat of potential damage from global climate changes. Finding ways to alleviate these forces is the key to Taiwan’s future social and economic development. This study examines the economic and environmental impacts when ethanol, conventional electricity and pyrolysis-based electricity are available alternatives. Biochar, as one of the most important by-product from pyrolysis, has the potential to provide significant environmental benefits. Therefore, alternative uses of biochar are also examined in this study. In addition, because planting energy crops would change the current land use pattern, resulting in significant land greenhouse gases (GHG) emissions, this important factor is also incorporated. Results show that bioenergy production can satisfy part of Taiwan’s energy demand, but net GHG emissions offset declines if ethanol is chosen. Moreover, at high GHG price conventional electricity and ethanol will be driven out and pyrolysis will be a dominant technology. Fast pyrolysis dominates when ethanol and GHG prices are low, but slow pyrolysis is dominant at high GHG price, especially when land GHG emissions are endogenously incorporated. The results indicate that when land GHG emission is incorporated, up to 3.8 billion kWh electricity can be produced from fast pyrolysis, while up to 2.2 million tons of CO2 equivalent can be offset if slow pyrolysis is applied.

Comparison of pollution prevention assessments for the facilities with and without energy star certification

The objective of this paper is to determine and compare the energy efficiency, energy savings, and pollution prevention for the two hypothetical facilities in USA, “XY”, and “BC”, with and without Energy Star® certification (Statement of Energy Performance [SEP]), respectively. Three different tools—Energy Assessment Spreadsheet (EAS), Economic Input Output Life Cycle Assessment (EIOLCA), and P2 calculators were used in assessing the energy usage and pollution prevention. The energy assessment survey was conducted using the EAS to determine the reduction in energy use and to perform the cost‐benefit analysis (CBA). A change in environmental impacts due to use of energy efficient lighting was assessed by the EIOLCA. The P2 was used in estimating the greenhouse gas (GHG) emissions and energy savings. Analysis showed a reduction of 58 MTCO2e (metric tons of CO2 equivalents) GHGs with a savings of $6878 for the facility “XY” and 493 MTCO2e GHGs with a savings of $55,089 for facility “BC”. The energy savings calculated with respect to square feet of area were observed to be 0.18 and 20.00 kWh/year, respectively, for XY and BC facilities. © 2014 American Institute of Chemical Engineers Environ Prog, 33: 1366–1372, 2014

Electricity Generation Expansion Planning with Environmental Impact Abatement: Case Study of Bangladesh

This paper analyzes utilization of renewable energy with domestic coal in place of import coal and oil in Bangladesh Power System from 2010-2030. Therefore, the modelling of long-term renewable and domestic coal utilization is examined in terms of expansion cost and environmental impacts. The results show that in 2030, the required electricity generation to fulfil future demand is estimated 162 TWh. Under the BAU scenario, the share of coal is 33% of total electricity generation mix. However, under the null coal import scenario the installed power plant from renewable sources increase to be 47 GW and coal utilization decreases to be 35 GW or 16% of total electricity generation share. The null coal import scenario reduces coal utilization by up to 52%. Under the limited coal and oil import scenarios, the share of coal becomes 60 GW or 27% of total electricity generation mix. In the economic and environmental perspective, more renewable based power plants need to be developed in order to reduce import coal and oil utilization in power generation. In the end of planning horizon, the BAU scenario emits as much as 96 million tons of CO2 equivalents, while the null coals import scenario successes to reduce emissions by 39 million tons from the BAU scenario's emissions.

Carbon Storage Potential of Forest Land: A Comparative Study of Cases in Finland and Croatia

Background and Purpose: The concentrations of greenhouse gases in the atmosphere have been increasing over the last hundred years in relation to the Fourth IPCC assessment report that highlighted human activities as a direct influence on climate changes. Since Croatia and Finland signed the Kyoto Protocol, they are both committed to fulfil international obligations of lowering GHG’s emissions, enhancing the storage, as well as protecting and enhancing the current pools where the forestry sector has a prominent role. These obligations created a need for a review on carbon storage potentials for both countries with the aim of setting further scientific and management guidelines as the basic purpose of this research. Materials and Methods: Data collection was conducted within the scope of the Sort Term Scientific Mission (STSM) in the period from May 2 – July 22, 2009 in the Finnish Forest Research Institute in Joensuu. The research encompassed an overview of literature, personal contacts with scientists and experts from both countries (research institutes, ministries, the EFI branch office in Joensuu) and a field inspection which altogether provided an insight into the applied silvicultural and utilization activities. A significant data source were official documents and published project results on the carbon storage potential. Results and Discussion: Mitigation activities within the framework of the LULUCF project reduced the total emissions for 33.4 millions tons of CO2 equivalents in Finland in 2006 (this data has varied from 18 to 33.4 millions tons CO2 equivalents in the last fifteen years) while for Croatia the availability of such data is limited. Finland has some former agricultural land which may be afforested but not in the substantial share, while in Croatia such areas amount to around 1 million ha. According to the climate change scenario for Finland (FINADAPT), predicting the largest climate changes, the total forest growth nationwide is estimated to increase by 44% which will have positive Martina Tijardovic Croatian Forest Research Institute Jastrebarsko, Croatia martinat@sumins.hr Sanja Peric Croatian Forest Research Institute Jastrebarsko, Croatia impact on the forest carbon storage in the future. In Croatia there is no such kind of research. There is about 12.6 % of all forest land in Finland under protected forests (strictly protected areas about 3.6 %) in which enhancement of carbon storage potential may be enhanced. About 21% of the forests in Croatia (513 155 ha) are forests in some degradation stage in addition to about 500 ha of forests where management is prevented because of the land mines. These areas present a potential for carbon storage enhancement. Forest fires pose a great threat to carbon pools especially in the Croatian karst areas where the total of 251 901 ha of the Croatian land area burned in the period 1992-2007, which in average amounts to 15 744 ha annually. Nevertheless, Finland and Croatia do not undertake any significant current deforestation activities. Conclusions: Even though Croatia and Finland have the same goals, they also show significant differences in relation to the already finished, current and planned scientific activities, legislation, implementation, natural conditions and constrains of CO2 sequestration and storage. It is estimated that a significant potential in Finland lies in the reduction of CO2 emissions through substitution effects, protection of stored carbon pools in forest ecosystems, avoiding the changes in land use, etc. Croatia, on the other hand, has a significant potential through afforestation activities on uncovered forest and abandoned agricultural lands. Further research on the categorisation of land, appropriate species and provenances selection is necessary. The effects of individual measures on emission reduction and carbon balance by forests are small on the national, as well as on the European scale, but if combined together the overall effects present a great potential to fulfill international obligations in both countries.

The carbon footprint of an Australian satellite haemodialysis unit

This study aimed to better understand the carbon emission impact of haemodialysis (HD) throughout Australia by determining its carbon footprint, the relative contributions of various sectors to this footprint, and how contributions from electricity and water consumption are affected by local factors. Activity data associated with HD provision at a 6-chair suburban satellite HD unit in Victoria in 2011 was collected and converted to a common measurement unit of tonnes of CO2 equivalents (t CO2-eq) via established emissions factors. For electricity and water consumption, emissions factors for other Australian locations were applied to assess the impact of local factors on these footprint contributors. In Victoria, the annual per-patient carbon footprint of satellite HD was calculated to be 10.2t CO2-eq. The largest contributors were pharmaceuticals (35.7%) and medical equipment (23.4%). Throughout Australia, the emissions percentage attributable to electricity consumption ranged from 5.2% to 18.6%, while the emissions percentage attributable to water use ranged from 4.0% to 11.6%. State-by-state contributions of energy and water use to the carbon footprint of satellite HD appear to vary significantly. Performing emissions planning and target setting at the state level may be more appropriate in the Australian context. What is known about the topic? Healthcare provision carries a significant environmental footprint. In particular, conventional HD uses substantial amounts of electricity and water. In the UK, provision of HD and peritoneal dialysis was found to have an annual per-patient carbon footprint of 7.1t CO2-eq. What does this paper add? This is the first carbon-footprinting study of HD in Australia. In Victoria, the annual per-patient carbon footprint of satellite conventional HD is 10.2t CO2-eq. Notably, the contributions of electricity and water consumption to the carbon footprint varies significantly throughout Australia when local factors are taken into account. What are the implications for practitioners? We recommend that healthcare providers consider local factors when planning emissions reduction strategies, and target setting should be performed at the state, as opposed to national, level. There is a need for more comprehensive and current emissions data to enable healthcare providers to do so.

Vision 2023: Feasibility analysis of Turkey's renewable energy projection

Electricity consumption of Turkey at the year 2023 is estimated to be around 530,000 GWh. Turkey plans to supply 30% or 160,000 GWh of this demand from renewable energy sources according to the recently avowed government agenda Vision 2023. However, the current installed renewable energy capacity is around 60,000 GWh. Detailed literature analysis showed that only wind and solar energy potential in Turkey can solely supply this demand. In this study, two different scenarios were generated to analyse the cost and environmental impacts of supplying this demand. Scenario 1, which is derived from the official Vision 2023 targets, suggests supplying this demand from wind, solar, geothermal energy and hydropower. The total projected cost based on Scenario 1 is estimated to be $31.000 billion and annual greenhouse gas emissions of 1.05 million tonnes of CO2 equivalent. According to Scenario 2 or the contrary setup it is assumed that the required demand gap could not be supplied from new renewable energy investments but equally from coal and natural gas. The projected cost is estimated to be around $8.000 billion and annual greenhouse gas emissions at appalling 71.30 million tonnes of CO2 equivalent. Assuming carbon tax at the year 2023 to be $50 per tonne of CO2 emitted, supplying the demand from renewable energy sources according to Scenario 1 would generate savings worth nearly $2.175 billion from environmental taxes annually. Thus, making the payback time of the renewable energy investments less than 15 years.

Excessive meat consumption in Brazil: diet quality and environmental impacts.

To evaluate red and processed meat intake, and the impact meat consumption has on diet quality and the environment. A large cross-sectional health survey performed in São Paulo, Brazil. Diet was assessed by two 24 h dietary recalls. Usual intakes were calculated using the Multiple Source Method. The World Cancer Research Fund recommendation of an average of 71.4 g/d was used as the cut-off point to estimate excessive red and processed meat consumption. To investigate the relationship between meat consumption and diet quality we used the Brazilian Healthy Eating Index Revised. The environmental impact was analysed according to estimates of CO2 equivalent emissions from meat consumption. Brazilians (n 1677) aged 19 years and older were studied. The mean red and processed meat intake was 138 g/d for men and 81 g/d for women. About 81% of men and 58% of women consumed more meat than recommended. Diet quality was inversely associated with excessive meat intake in men. In Brazil alone, greenhouse gas emissions from meat consumption, in 2003, were estimated at approximately 18,071,988 tonnes of CO2 equivalents, representing about 4% of the total CO2 emitted by agriculture. The excessive meat intake, associated with poorer diet quality observed, support initiatives and policies advising to reduce red and processed meat intake to within the recommended amounts, as part of a healthy and environmentally sustainable diet.

Utilization of Biochar in Sugarcane and Sugar-Industry Management

The sugarcane industry in many parts of the world produces food and energy (stationary and fuel). The industry is well positioned to offer greenhouse gas abatement and climate change mitigation. The thermal conversion, via a slow pyrolysis process, of cane residues such as green harvest trash and bagasse can produce thermal or electrical energy as well as biochar. Studies have shown that a commercial slow pyrolysis unit could generate over 1 MWhr of electricity from every two tonnes of trash (dry basis), with a biochar recover of between 31.3–33.6 %. Due to its highly stable nature, biochar has recently been suggested as a sequestration pathway to remove CO2 from the atmosphere. One tonne of bagasse derived biochar would sequester in the order of 2.3 tonnes of CO2 equivalents. In addition to C sequestration, biochar has other significant benefits (when used as a soil amendment) such as offering improved soil quality, higher CEC and nutrient availability, and improved soil physical characteristics. This work demonstrates that biochar application can reduce emissions of greenhouse gases from cane soils, such as nitrous oxide. Biochars derived from cane trash and bagasse were applied in incubation studies to soils from the Burdekin region in Australia. We found declines in emissions of the greenhouse gas nitrous oxide (N2O), from urea-fertilised soil when bagasse biochar was applied at a rate of 10 t/ha. The agronomic performance of biochar is being assessed in a 15 plot trial conducted on a sugar cane property in the Tweed Valley, NSW. Biochars (from non-sugarcane sources) were tested using relevant controls. Each plot consists of 3 rows of cane and was 30 m in length to enable commercial-scale harvesting. Although no significant effects in yield have been recorded this trial is expected to continue for several more seasons allowing additional data on yield effects to be evaluated. Our work has demonstrated that implementing slow pyrolysis and biochar utilisation in the sugarcane industry has potential to provide (1) renewable energy (2) income from waste (3) climate mitigation through stabilisation of carbon and (4) climate mitigation through reduced emission of N2O from soil. Further research is required to demonstrate agronomic benefits of sugarcane biochars and to develop an understanding of how they may address soil constraints in these systems.

The Future of Fracking: New Rules Target Air Emissions for Cleaner Natural Gas Production

Natural gas is lauded as a cleaner-burning fuel than either coal or oil, but getting the fuel out of the ground can be a dirty process, especially given the widespread adoption of the technology known as hydraulic fracturing (“fracking”). Concerns about toxic air emissions from previously unregulated fracking sites led to the U.S. Environmental Protection Agency (EPA) announcement on 18 April 2012 of new and updated air pollution regulations for these facilities and certain other elements of oil and natural gas production and transmission.1 Compliance with the new regulations is expected to result in major reductions in emissions of methane and volatile organic compounds (VOCs), particularly from new fracked natural gas wells. The rules were a hot topic nationally, drawing more than 156,000 comments after the proposed version was released in mid-2011. Under the final rules, companies have until January 2015 to fully phase in the control measures needed; by comparison, the initial proposal called for a 60-day phase-in for many major requirements. The EPA says about half of all new wells already use the equipment needed to capture the targeted emissions.2 A hydraulic fracturing natural gas drilling rig on the eastern Colorado plains. In 2009 there were more than 38,000 natural gas wells in the state. Many environmental groups consider the new regulations an improvement over the existing situation, but they tend to be disappointed much more wasn’t done. “This is quite a milestone,” says Jeremy Nichols, Climate and Energy Program director for the advocacy group WildEarth Guardians, one of two groups that filed suit against the EPA in 2009 to force action on the issue. “But is the work done? No, of course not. It’s a floor to build on, providing a minimal level of protection.” The oil and natural gas industry has its own concerns about the new rules but has indicated it can work with them. In a press release issued the day the rules were announced, Howard Feldman, director of regulatory and scientific affairs for the American Petroleum Institute, said, “EPA has made some improvements in the rules that allow our companies to continue reducing emissions while producing the oil and natural gas our country needs.”3

Impact on carbon footprint: a life cycle assessment of disposable versus reusable sharps containers in a large US hospital

Hospitals are striving to reduce their greenhouse gas (GHG) emissions. Targeting supply chain points and replacing disposable with reusable items are among recommendations to achieve this. Annually, US hospitals use 35 million disposable (DSC) or reusable sharps containers (RSC) generating GHG in their manufacture, use, and disposal. Using a life cycle assessment we assessed the global warming potential (GWP) of both systems at a large US hospital which replaced DSC with RSC. GHG emissions (CO(2), CH(4), N(2)O) were calculated in metric tons of CO(2) equivalents (MTCO(2)eq). Primary energy input data was used wherever possible and region-specific conversions used to calculate the GWP of each activity. Unit process GHGs were collated into manufacture, transport, washing, and treatment and disposal. The DSC were not recycled nor had recycled content. Chemotherapy DSC were used in both systems. Emission totals were workload-normalized per 100 occupied beds-yr and rate ratio analyzed using Fisher's test with P ≤0.05 and 95% confidence level. With RSC, the hospital reduced its annual GWP by 127 MTCO(2)eq (-83.5%) and diverted 30.9 tons of plastic and 5.0 tons of cardboard from landfill. Using RSC reduced the number of containers manufactured from 34,396 DSC annually to 1844 RSC in year one only. The study indicates sharps containment GWP in US hospitals totals 100,000 MTCO(2)eq and if RSC were used nationally the figure could fall by 64,000 MTCO(2)eq which, whilst only a fraction of total hospital GWP, is a positive, sustainable step.

An empirical analysis of the Carbon Financial Instrument

This study provides an empirical investigation of the price volatility—trading volume relationship for the Carbon Financial Instrument (CFI). A CFI is a financial contract that is traded on the Chicago Climate Exchange (CCX) and represents the right to emit 100 metric tons of CO2 equivalent. CFI contracts differ from one another on the basis of their allocation year to CCX member firms, referred to as their respective Vintage year. We provide evidence indicating a positive contemporaneous relationship between price changes and trading volume for the different CFI Vintage contracts. Employing bivariate VAR models that adjust for trade duration, we find that CFI price volatility and trading volume are persistent across time. Furthermore, we provide evidence indicating that lagged volume increases price volatility, in addition to lagged price volatility increasing trading volume levels in the CCX market. Our results are in agreement with prior research documenting significant positive price volatility—volume relationships in traditional equity markets.

A whole farm systems analysis of greenhouse gas emissions of 60 Tasmanian dairy farms

The Australian dairy industry contributes ∼1.6% of the nation's greenhouse gas (GHG) emissions, emitting an estimated 8.9 million tonnes of CO2 equivalents (tCO2e)/annum (DCC, 2008). This study examined GHG emissions of 60 Tasmanian dairy farms using the Dairy Greenhouse gas Abatement Strategies (DGAS) calculator, which incorporates International Panel on Climate Change (IPCC) and Australian inventory methodologies, algorithms and emission factors. Sources of GHG emissions including pre-farm embedded emissions associated with key farm inputs (i.e., grains/concentrates, forages and fertilizers) and on-farm emissions from CO2, CH4 and N2O are estimated by DGAS software. A detailed description of GHG calculations and functionality of DGAS software are provided. Total farm GHG emissions of 60 Tasmanian dairy farms, as estimated with DGAS, ranged between 704 and 5839tCO2e/annum, with a mean of 2811tCO2e/annum. Linear regression analyses showed that 0.93 of the difference in total farm GHG emission was explained by milk production. The estimated mean GHG emission intensity of milk of production was 1.04kgCO2e/kg fat and protein corrected milk (FPCM; ranged between 0.83 and 1.39tCO2e/tFPCM) with a standard deviation of 0.13. Stepwise multiple linear regression analysis showed that feed conversion efficiency (kgFPCM/kgdry matter (DM) intake) and N based fertilizer application rate explained 0.60 of the difference in the GHG emissions due to milk production from these pastoral based dairy systems. Estimated per cow and per hectare emission intensity was 6.9±1.46tCO2e/cow and 12.6±4.37tCO2e/ha, respectively. Stepwise multiple linear regression analysis showed that DM intake per cow (tDM intake/cow/lactation) explained 0.86 of the variability in per cow GHG emissions intensity, while milk production/hectare (tFPCM/ha) explained 0.92 of the variability in per hectare GHG emission intensity. Given the influence that feed conversion efficiency and/or N based fertilizer application rates had on all GHG emissions intensities, it is clear that these factors should be key target areas to lower the intensity of emissions associated with dairying in Tasmania.This paper is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors: K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson.

The role of high-speed rail in mitigating climate change – The Swedish case Europabanan from a life cycle perspective

In this paper a life cycle perspective is used to analyse Europabanan, a proposed high-speed rail track in Sweden. The life cycle emissions reductions are found to be 550,000 tons of CO 2-equivalents per annum by 2025/2030 with almost 60% of this coming from a shift from truck to rail freight and 40% from a shift from air and road travel to high-speed rail travel. In contexts similar to Sweden, it is thus an important issue whether a large increase is required in freight rail capacity anyway, since high-speed rail investments may not be justified for the passenger markets alone. The study also indicates that a substantial share of emissions due to construction of the new railway could be counterbalanced through the reduced need for building and maintaining roads and airports, and for manufacturing cars.

The Evolution of Environmental Management Philosophy Under Rapid Economic Development in China

The International Energy Agency (IEA 2010) recently reported that China consumed 2.25 × 109 tons of oil equivalents in 2009, i.e., China had become the world’s largest energy consumer. Subsequently, the National Energy Bureau of China stated that the IEA report was inaccurate (Gai 2010). This debate reminds us the two important conferences held in the end of 2009. At the first conference (the Climate Change Conference of United Nations), the Intergovernmental Panel on Climate Change (IPCC 2009) stated that global climate changes might be more severe than predicted. Although there is disagreement about the IPCC report (Folster and Nystrom 2010), most scientists believe that climate change is a real and severe challenge and that controlling greenhouse gas emission is the most effective way to reduce global warming (Tollefson 2010). The goal of the second conference (The 2009 United Nations Climate Change Conference) was to develop a new emissions-reduction timetable. The representative of each country balanced the national interest in maintaining economic development against the international need to reduce global warming. The major countries finally made commitments to reduce emissions (Ding et al. 2009). The Sustainable Development Strategy Research Group of Chinese Academy of Sciences found that, during technological advancement, the developed countries greatly increased their C emissions, and in the absence of restrictive policy and resource constraints, per capita C emissions increased with increases in per capita GDP. In part because of the oil crisis in 1970s and the constraints of Kyoto Protocol, per capita and total C emissions have peaked and begun to decline in most developed countries (Wu and Wang 2009; Ding et al. 2009). C emissions per unit of GDP in China are also decreasing, but greater reductions are possible. From 1990 to 2005, China reduced energy consumption per unit of GDP by 47% and C emissions per unit of GDP by 45% (Wu and Wang 2009). Considering stage of development, population growth, increase of per capita consumption, and cost effectiveness, China can better reduce C emissions by reducing energy consumption. Reducing poverty and solving other social problems, however, make it difficult to reduce C emissions. While trying to reduce energy consumption and C emissions per unit of GDP, China has also recognized the value of terrestrial ecosystem management and vegetation restoration for C fixation. The estimated net C fixation of terrestrial ecosystems in China was 3.8–5.2 × 109 tons from 1980 to 2000, equivalent to 30% of the emissions from fossil fuel combustion over the same period (Piao et al. 2009). In 2008 in China, forests covered about 195 million ha (5% of the world total) and plantations covered 62 million ha (29% of the world total) (Ren et al. 2010). About 5.9–6.2 × 109 tons of C is stored in Chinese vegetation (Yu and Li 2009). The total C storage of all forests in China was about 1.5 × 109 tons during 1980–2000, with the afforestation projects between 1970 and 1990 contributing 450 million tons. In 2004 alone, the net absorption of Chinese forests was roughly 500 million tons of CO2 equivalents, accounting for more than 8% of the national greenhouse gas emissions over the same period (Yu and Li 2009). Over the past 10 years, the Chinese government has invested 70 × 109 US dollars in plantation and forest restoration projects (Ren et al. 2010). The potential C fixation of current restoration projects in China is approximately 20 × 109 tons with a duration of about 100 years. In the next 50 years, implementation of forestry projects is expected to increase forest C storage per year by 182–194 million tons (Yu and Li 2009).

Oil Sands Development: A Health Risk Worth Taking?

As traditional petroleum supplies dwindled and prices soared over the past few years, oil companies have shifted their attention to oil sands, a mix of sand, water, and a heavy, viscous hydrocarbon called bitumen that can be converted to oil. With the plunge in oil prices in fall 2008, many producers began canceling or postponing plans to expand oil sands development projects, but this turn of events could yet reverse, as Canada’s vast oil sands deposits are lauded as a secure source of imported oil for the United States. At the same time, however, oil sands present troubling questions in terms of the environmental health effects associated with their development.

Applying fundamental data to reduce the carbon dioxide footprint of aluminum smelters

The aluminum smelting process is a strong emitter of CO2 with three major contributions: that arising from electrical energy generation and its utilization, the process conversion contribution linked with anode consumption and anode production, and the greenhouse gas equivalents of the intermittent perfluorocarbon (PFC) emissions. Fundamental studies of alumina solubility, the electrochemical mechanism for triggering the onset of PFC emissions, and the importance of both mixing and current density on the speed of termination of anode effects, help define better paths for process operation. In conjunction with advising prebake aluminum smelters on process optimization, the authors have successfully tested the differences in theory and practice, and applied fundamentals in the operating environment to change some of the installed control strategies, termination mechanisms, and work practices. These changes have improved performance and reduced the CO2 footprint. The overall process reductions achieved exceed 2.24 million tonnes of CO2 equivalents per year in smelters producing less than 3 million tonnes of aluminum per year.

Assessing the End-of-Life Impacts of Buildings

This paper builds on previous research on end of life of products by synthesizing some of the theories proposed in the literature and presenting a method for environmental decision-making related to buildings. This is achieved through different solutions, but most significantly through the use of hybrid life-cycle assessment and the definition of allocation boundaries in a way that decreases the uncertainty associated with technologicalforecasting. Results show that there is no significant difference between the results of two major end-of-life assessment approaches (attributional and consequential), and that the choice between the use of one or the other for buildings may not be a critical decision. Assessing the impacts of recycling polices requires accounting for product substitutions, market analysis, and the full supply chain impacts of the recycling chains. Increasing the recycling of concrete from deconstructed buildings from the current 27% rate to 50% could yield a 2-3% (2.7-5.6 million metric tons of CO2 equivalents) reduction in buildings' greenhouse gas emissions, or the equivalent of removing 408,000-847,000 typical cars from U.S. roads.

Environmental assessment of digestibility improvement factors applied in animal production

Background, Aims and Scope. Many feed ingredients are not fully digested by livestock. However, the addition of digestibilityimproving enzymes to the feed can improve the absorption of e.g. energy and protein and thereby enhance the nutrient value of the feed. Feed production is a major source of environmental impacts in animal production, and it is obvious to assume that enzyme supplementation can help to reduce the environmental impact of animal production. The purpose of the study is, therefore, to assess and compare the environmental burdens of the supplements and compare them with the savings made when enzymes are used in animal production. The properties of enzymes vary considerably and the study takes as its starting point a particular enzyme product, Ronozyme WX CT. Ronozyme WX CT is a xylanase which depolymerises xylans (a group of dietary fibres found in cereal cell walls) into smaller units. The product is a widely accepted means of improving the energy value and the protein digestibility of pig and poultry feed. The study relates to Ronozyme WX CT used for fattening pigs produced in Denmark. Methods. Lifecycle assessment is used as the analytical method, and Ronozyme WX CT production and reductions in feed consumption are modelled using SimaPro 7.0.2. Data on Ronozyme WX CT production are derived from Novozymes' production facilities in Denmark. Other data are derived from the literature and from public databases. Changes in feed consumption are determined by modelling in AgroSoft feed optimisation software. Guidelines from the Intergovernmental Panel on Climate Change (IPCC) are used to estimate reductions in the emission of greenhouse gases resulting from reduced manure generation and changed manure composition. Results. The study shows that the use of Ronozyme WX CT to increase the nutritional value of pig feed is justified by major advantages in terms of reduced potential contribution to global warming, acidification and photochemical ozone formation and reduced use of energy, and in most cases also nutrient enrichment and use of agricultural land. Ronozyme WX CT (xylanase) is often used together with Ronozyme P5000 CT (phytase) and together the two products can contribute considerably to reducing a broad range of environmental impacts from pig production. Discussion. Reduced contribution to acidification and nutrient enrichment is partly driven by reduced feed consumption and partly reduced N-emissions with manure resulting from reduced protein content of the feed. Sensitivity analyses of a range of parameters show that the observed advantages are generally robust although exact magnitudes of environmental advantages are associated with much variation and uncertainty. It should, however be noted that certain changes (e.g. of feed prices) may turn contributions to nutrient enrichment and use of agricultural land into trade-offs. Conclusions. Improvement of energy and protein value of pigfeed by application of Ronozyme xylanase and following feed savings reduces impact on environment per unit of pig-meat produced, and the enzyme product contributes to a sustainable development the Danish pork meat supply. Recommendations. Digestibility-improving enzymes are a promising means of reducing the environmental impact of pig production. The greenhouse gas reducing potential of Ronozyme WX CT in Danish pig production has been estimated at 5% and in the order of 4 million tons of CO2 equivalents if the results are extended to the whole of Europe. Use of Ronozyme WX CT is driven by overall cost savings in animal production, and it is therefore recommended that digestibility-improving enzymes are given more attention as a cost-efficient means of reducing greenhouse gas emissions.

Greenhouse gas emissions from a constructed wetland in southern Sweden

This paper investigates the greenhouse gas emissions from a Swedish wetland, constructed to decrease nutrient content in sewage treatment water. To evaluate the effect of the construction in terms of greenhouse gas emissions we carried out ecosystem-atmosphere flux measurements of CO2, CH4 and N2O using a closed chamber technique. To evaluate the importance of vascular plant species composition to gas emissions we distributed the measurement plots over the three dominating plant species at the field site, i.e., Typha latifolia, Phragmites australis and Juncus effusus. The fluxes of CO2 (total respiration), CH4 and N2O from vegetated plots ranged from 1.39 to 77.5 (g m-2 day-1), -377 to 1387 and -13.9 to 31.5 (mg m-2 day-1) for CO2, CH4 and N2O, respectively. Presence of vascular plants lead as expected to significantly higher total respiration rates compared with un-vegetated control plots. Furthermore, we found that the emission rates of N2O and CH4 was affected by presence of vascular plants and tended to be species-specific. We assessed the integrated greenhouse warming effect of the emissions using a Global Warming Potential over a 100-year horizon (GWP100) and it corresponded to 431 kg CO2 equivalents m-2 day-1. Assuming a 7-month season with conditions similar to the study period this is equal to 90 tonnes of CO2 equivalents annually. N2O emissions were responsible for one third of the estimated total greenhouse forcing. Furthermore, we estimated that the emission from the forested bog that was the precursor land to Magle constructed wetland amounted to 18.6 tonnes of CO2 equivalents annually. Hence, the constructed wetland has increased annual greenhouse gas emissions by 71.4 tonnes of CO2 equivalents for the whole area. Our findings indicate that management processes in relation to wetland construction projects must consider the primary function of the wetland in decreasing eutrophication, in relation to other positive aspects on for instance plant and animal life and recreation as well as possible negative climatic aspects of increased emissions of CH4 and N2O. (Less)

Anaerobic digestion as a sustainable solution for biosolids management by the Montreal Metropolitan Community

The Quebec Waste Management Policy (1998-2008) is requesting that the municipalities prepare a waste management plan, including a global objective of 60% of these wastes to be diverted from landfill sites by reduction, re-usage, recycling and valorization. Around 5.8 million tons of wastes were generated on the territory of the Montreal Metropolitan Community in 2001 for a population of about 3.5 millions citizens. In this paper, we present different management scenarios in which anaerobic digestion was used as a valorization step, focusing on the energetic value of the methane produced and the reduction in greenhouse gas (GHG) emissions. The four scenarios prepared cover the valorization of the organic fraction of municipal solid wastes, green wastes and excess sludge and showed potential methane generation of 17-140 Mm3 with a GHG reduction of 62,000-500,000 tons of CO2-equivalents.