Life cycle assessment of clinker production using refuse‐derived fuel: A case study using refuse‐derived fuel from Tehran municipal solid waste

One of the techniques used to dispose of 4,000 tons per day (TPD) of non‐recyclable waste from Tehran is to burn it as an alternative fuel in cement kilns. This practice reduces emissions from landfills, prevents the loss of waste energy, and conserves fossil fuel resources. The aim of our study was to conduct a life cycle assessment (LCA) of clinker production in cement kilns using a combination of natural gas, mazut, a form of heavy, low‐quality fuel oil, and refuse‐derived fuel (RDF) from Tehran. We used SimaPro 7.1 software to perform an LCA of 1 kilogram (kg) of clinker produced using the following fuel combinations: the first scenario involved natural gas consumption alone, the second scenario involved a combination of natural gas and mazut, with the mazut providing 5% to 30% of the heating value needed to produce cement clinker in the kiln, and the third scenario involved a combination of natural gas and RDF (providing 5% to 30% of the heating needed in the kiln). The impact categories in the LCA of global warming, eutrophication, and acidification were assessed by the Center of Environmental Science of Leiden University (Centrum voor Milieukunde Leiden—CML) CML 2000 method. The results indicated that the third scenario, involving natural gas and RDF, reduced acidification by 2.14–11.5% and global warming by 0–1.3% relative to the first scenario involving the use of only natural gas. In addition, we observed a 0.65–3.81% reduction in acidification and a 0.9–3.8% reduction in global warming under the third scenario compared with the second scenario (co‐firing of natural gas and mazut). The amount of nitrogen oxides (NO_X) emitted from the combustion of the Tehran RDF was greater than that was emitted when burning mazut. Therefore, reduction of nitrogen from the RDF composition is necessary. This study indicates that the use of Tehran RDF (with reduced nitrogen) in Tehran cement kilns does not increase cement kiln NO_X, sulfur dioxide (SO₂), and carbon dioxide (CO₂) emissions; however, we need to conduct additional investigation into the chemical composition of the Tehran waste before using solid waste in place of fossil fuels.     

Forestry-based carbon sequestration projects in Africa: Potential benefits and challenges

Carbon sequestration through forestry and agroforestry can help mitigate global warming. For Africa, carbon sequestration also represents an opportunity to fund sustainable development through financial inflows. However, with a low share of global carbon trade, there are strong concerns that African countries are losing out on this valuable opportunity. Through a comprehensive review of 23 carbon sequestration projects across 14 countries, this paper discusses ways to overcome critical challenges to scale up carbon investments in Africa. These projects are expected to sequester 26.85 million tCO₂ beyond the baseline situation. Within the continent, East Africa is the preferred destination for carbon investors. Most projects are non‐Kyoto compliant and represent voluntary emission reductions. While project benefits such as increased local incomes and improved natural resources are promising, there are concerns that conversion of grasslands into tree plantations can harm local ecosystems. Insecure land tenure constrains new investments and increases the risk that local communities will lose access to forests. Another challenge is that projects with smallholders have high transaction costs. These costs can be overcome by building strong community institutions and simplifying project guidelines. To attract more projects, African governments will need to build their capacity to identify relevant opportunities.     

Energy balance and global warming potential of corn straw-based bioethanol in China from a life cycle perspective

As the second largest corn producer in this world, China has abundant corn straw resources. The study assessed the energy balance and global warming potential of corn straw-based bioethanol production and utilization in China from a life cycle perspective. The results revealed that bioethanol used as gasoline and diesel blend fuel could reduce global warming potential by 10%–97% and 4%–96%, respectively, as compared to gasoline and diesel for transport. The total global warming potential, net global warming potential, net energy, and Net Energy Ratio per MJ ethanol generated from corn straw-based bioethanol system are estimated to be 0.20 kg CO₂-eq, 0.012 kg CO₂-eq, 0.60 MJ, and 1.87, respectively. By using sensitivity analysis, we found that the collected coefficient and compressing density of straw have a more obvious influence on energy balance; transportation distance has a more obvious influence on global warming potential emission factor. The by-products may be utilized as fertilizer, animal feed, cement replacement, or high-value lignin chemicals, which make a contribution to offsetting 0.28 MJ per MJ ethanol of energy consumption.     

Environmental impacts of different food waste resource technologies and the effects of energy mix

The environmental impacts of food waste management strategies and the effects of energy mix were evaluated using a life cycle assessment model, EASEWASTE. Three different strategies involving landfill, composting and combined digestion and composting as core technologies were investigated. The results indicate that the landfilling of food waste has an obvious impact on global warming, although the power recovery from landfill gas counteracts some of this. Food waste composting causes serious acidification (68.0 PE) and nutrient enrichment (76.9 PE) because of NH₃ and SO₂ emissions during decomposition. Using compost on farmland, which can marginally reduce global warming (−1.7 PE), acidification (−0.8 PE), and ecotoxicity and human toxicity through fertilizer substitution, also leads to nutrient enrichment as neutralization of emissions from N loss (27.6 PE) and substitution (−12.8 PE). A combined digestion and composting technology lessens the effects of acidification (−12.2 PE), nutrient enrichment (−5.7 PE), and global warming (−7.9 PE) mainly because energy is recovered efficiently, which decreases emissions including SO₂, Hg, NO_x, and fossil CO₂ during normal energy production. The change of energy mix by introducing more clean energy, which has marginal effects on the performance of composting strategy, results in apparently more loading to acidification and nutrient enrichment in the other two strategies. These are mainly because the recovered energy can avoid fewer emissions than before due to the lower background values in power generation. These results provide quantitative evidence for technical selection and pollution control in food waste management.     

Processing of Straw/Corn Stover: Comparison of Life Cycle Emissions

The LCA emissions from four renewable energy routes that convert straw/corn stover into usable energy are examined. The conversion options studied are ethanol by fermentation, syndiesel by oxygen gasification followed by Fischer Tropsch synthesis, and electricity by either direct combustion or biomass integrated gasification and combined cycle (BIGCC). The greenhouse gas (GHG) emissions of these four options are evaluated, drawing on a range of studies, and compared to the conventional technology they would replace in a western North American setting. The net avoided GHG emissions for the four energy conversion processes calculated relative to a “business as usual” case are 830 g CO₂e/kWh for direct combustion, 839 g CO₂e/kWh for BIGCC, 2,060 g CO₂e/L for ethanol production, and 2,440 g CO₂e/L for FT synthesis of syndiesel. The largest impact on avoided emissions arises from substitution of biomass for fossil fuel. Relative to this, the impact of emissions from processing of fossil fuel, e.g., refining of oil to produce gasoline or diesel, and processing of biomass to produce electricity or transportation fuels, is minor.     

LCA study of photovoltaic systems based on different technologies

This work deals with the application of a Life Cycle Assessment approach for evaluating the environmental and energy impacts ascribed to the production of photovoltaic (PV) cells of first and second generations. PV technologies based on silicon and CuInSe₂ (CIS) thin films were taken into account herein. PV systems prepared with amorphous silicon (a-Si) showed a low environmental impact and short energy payback time when compared to those ones obtained using crystalline silicon (c-Si). PV technologies associated with mono-crystal (mono-Si) and polycrystalline silicon (multi-Si) showed large emissions of CO₂, nitrogen oxides, non-methane volatile organic compounds, particulates, and SO₂ into air per square meter of PV panel processed. In addition, these technologies displayed a significant fossil fuel demand, biological oxygen demand, and global warming potential, which make them eco-unfriendly. Ribbon silicon (ribbon-Si) and CIS thin films showed intermediate impact scores, but further improvements in their production chain are needed before these devices are commercially used. The technologies examined herein were categorized in first- and second-generation technologies in order to compare their environmental impact and conversion efficiency. Much attention was also paid to the development of third-generation PV cells with improved conversion efficiencies and lower environmental impacts.     

The injustice of climate change: voices from Africa

Farmers and pastoralists in Africa are remarkably consistent across countries in how they report climate is changing. These changes are still relatively small but, combined with the effects of chronic poverty, disease and environmental degradation, are already having severe human consequences. The changes are consistent with what is expected to occur due to man-made global warming and will increase. Women are especially impacted. Africa is least responsible for greenhouse gas emissions, but will suffer some of the most damaging consequences. Adaptation is essential. This will require finance from international sources. However, there is much African governments can and should do to start. Boosting adaptation to current climatic variability and shocks and tackling poverty will bring benefits today and for the future.     

Panel heterogeneous distribution analysis of trade and modernized agriculture on CO2 emissions: The role of renewable and fossil fuel energy consumption

In line with the global target of reducing climate change and its impact, this study explored the causal relationship between CO₂ emissions, modernized agriculture, trade openness, aggregate and disaggregate energy consumption in 14 African countries from 1990–2013 using a panel quantile estimation procedure. The empirical results showed that value addition to agricultural commodities declines CO₂ emissions in countries with high pollution levels. The study revealed a positive nexus between CO₂ emissions and energy consumption homogeneously distributed across quantiles. Trade openness was found to lower CO₂ emissions in countries with lower and higher levels of environmental pollution. While fossil fuel energy consumption was found to exacerbate CO₂ emissions, renewable energy consumption confirmed its mitigating effect on environmental pollution. The institution of climate‐smart agricultural options will sustainably increase productivity and income while adapting to climate change by reducing greenhouse gas emissions. Diversification of energy technologies with clean and modern energy sources like renewables avoid the over‐dependence on fossil fuels for agricultural purposes. Trade policies can stimulate flows of technology and investment opportunities for specialization in production and economies of scale. Hence, the consideration of policies that boost agricultural sector productivity and create an efficient market for international trade in Africa will help in improving livelihoods.     

The Effect of Local Biomass Projects on Energy Balance and GHG Emission: A Life Cycle Approach

Emerging attention has been given to the use of biomass in local areas for its contribution to reducing fossil fuel dependence and mitigating global warming. The objective of the present study is to develop a method that quantitatively assesses the effects of local biomass projects on fossil fuel consumption and greenhouse gas (GHG) emission. A practical method based on a life cycle approach is proposed and applied to a case of bioethanol project in Miyako Islands of Japan. The project is aiming to produce bioethanol from molasses within the islands, and to replace the entire gasoline consumed in the islands to E3 fuel (i.e., a mixture of 3% ethanol and 97% gasoline by volume). The assessment using the developed method revealed that, first, the complete shift from gasoline to E3 fuel allows for decreases in fossil fuel consumption and GHG emission. Second, the performance of the project is improved by the integration of the ethanol plant and the sugar factory. Moreover, the assessment found that, in small-scale bioethanol projects, the contribution of capital goods to life cycle fuel consumption and GHG emission is not negligible.     

Ethanol fuels: Energy security,economics, and the environment

Problems of fuel ethanol production have been the subject of numerous reports, including this analysis. The conclusions are that ethanol: does not improve U.S. energy security; is uneconomical; is not a renewable energy source; and increases environmental degradation. Ethanol production is wasteful of energy resources and does not increase energy security. Considerably more energy, much of it high- grade fossil fuels, is required to produce ethanol than is available in the energy output. About 72% more energy is used to produce a gallon of ethanol than the energy in a gallon of ethanol. Ethanol production from corn is not renewable energy. Its production uses more non- renewable fossil energy resources in growing the corn and in the fermentation/distillation process than is produced as ethanol energy. Ethanol produced from corn and other food crops is also an unreliable and therefore a non-secure source of energy, because of the likelihood of uncontrollable climatic fluctuations, particularly droughts which reduce crop yields. The expected priority for corn and other food crops would be for food and feed. Increasing ethanol production would increase degradation of agricultural land and water and pollute the environment. In U.S. corn production, soil erodes some 18- times faster than soil is reformed, and, where irrigated, corn production mines water faster than recharge of aquifers. Increasing the cost of food and diverting human food resources to the costly and inefficient production of ethanol fuel raise major ethical questions. These occur at a time when more food is needed to meet the basic needs of a rapidly growing world population.     

A model for the CO2 capture potential

Global warming is a result of increasing anthropogenic CO₂ emissions, and the consequences will be dramatic climate changes if no action is taken. One of the main global challenges in the years to come is therefore to reduce the CO₂ emissions.Increasing energy efficiency and a transition to renewable energy as the major energy source can reduce CO₂ emissions, but such measures can only lead to significant emission reductions in the long-term. Carbon capture and storage (CCS) is a promising technological option for reducing CO₂ emissions on a shorter time scale.A model to calculate the CO₂ capture potential has been developed, and it is estimated that 25 billion tonnes CO₂ can be captured and stored within the EU by 2050. Globally, 236 billion tonnes CO₂ can be captured and stored by 2050. The calculations indicate that wide implementation of CCS can reduce CO₂ emissions by 54% in the EU and 33% globally in 2050 compared to emission levels today.Such a reduction in emissions is not sufficient to stabilize the climate. Therefore, the strategy to achieve the necessary CO₂ emissions reductions must be a combination of (1) increasing energy efficiency, (2) switching from fossil fuel to renewable energy sources, and (3) wide implementation of CCS.     

The role of climatic variations on migration and human health in Africa

In Africa, climatic variations, as typified by widespread rainfall fluctuations, are a prominent feature of the climate of the continent. The effects of these climatic variations are multifarious and affect the environmental, economic and social well-being of the societies concerned. This is particularly so since the majority of the people depend on rain supported agricultural production for their sustenance and livelihood. Any short-fall in the amount, frequency and manner of occurrence of the rains received, tends to reflect on the people's spatial behaviour, particularly as migration in trying to make up for the impact of the deficit. This paper describes the nature of climatic variations over the continent and highlights the extent to which climatic variations play a significant role in population movement and the health of peoples as documented in studies carried out in different parts of the region. An awareness of the implications of climatic variations as reviewed in this work suggests the need for better monitoring systems to measure the impacts of climatic variations. This will provide governments and all stakeholders with a proper perspective of the vagaries of climate and enhance the development of suitable policies to mitigate and alleviate the impact on the general populace of the affected areas. This is especially important in the face of changing world climate and its antecedant effects which are especially felt in developing societies.     

Strengthening Agricultural Research in Africa

Training programmes that involve agricultural researchers with farmers and extension field-workers have helped national agricultural research systems in sub-Saharan Africa to improve their communication with farmers. The International Institute of Tropical Agriculture (IITA) has worked with national crop research institutes and agricultural extension agencies in building communication links with farmers. In a continent where population growth still outstrips food production increases, feedback from farmers on performance of high-yielding crop varieties and on new farming techniques is essential in boosting food production.     

Projected Changes in Discharge in an Agricultural Watershed in Iowa

Our improved capability to adapt to the future changes in discharge is linked to our capability to predict the magnitude or at least the direction of these changes. For the agricultural United States Midwest, too much or too little water has severe socioeconomic impacts. Here, we focus on the Raccoon River at Van Meter, Iowa, and use a statistical approach to examine projected changes in discharge. We build on statistical models using rainfall and harvested corn and soybean acreage to explain the observed discharge variability. We then use projections of these two predictors to examine the projected discharge response. Results are based on seven global climate models part of the Coupled Model Intercomparison Project Phase 5 and two representative concentration pathways (RCPs 4.5 and 8.5). There is not a strong signal of change in the discharge projections under the RCP 4.5. However, the results for the RCP 8.5 point to a stronger changing signal related to larger projected increases in rainfall, resulting in increased trends, in particular, in the upper part of the discharge distribution (i.e., 60th percentile and above). Examination of two hypothetical agricultural scenarios indicates that these increasing trends could be alleviated by decreasing the extent of the agricultural production. We also discuss how the methodology presented in this study represents a viable approach to move forward with the concept of return period for engineering design and management in a nonstationary world.     

Do mitigation strategies reduce global warming potential in the northern U.S. corn belt?

Agricultural management practices that enhance C sequestration, reduce greenhouse gas emission (nitrous oxide [N?O], methane [CH?], and carbon dioxide [CO?]), and promote productivity are needed to mitigate global warming without sacrificing food production. The objectives of the study were to compare productivity, greenhouse gas emission, and change in soil C over time and to assess whether global warming potential and global warming potential per unit biomass produced were reduced through combined mitigation strategies when implemented in the northern U.S. Corn Belt. The systems compared were (i) business as usual (BAU); (ii) maximum C sequestration (MAXC); and (iii) optimum greenhouse gas benefit (OGGB). Biomass production, greenhouse gas flux change in total and organic soil C, and global warming potential were compared among the three systems. Soil organic C accumulated only in the surface 0 to 5 cm. Three-year average emission of N?O and CH was similar among all management systems. When integrated from planting to planting, N?O emission was similar for MAXC and OGGB systems, although only MAXC was fertilized. Overall, the three systems had similar global warming potential based on 4-yr changes in soil organic C, but average rotation biomass was less in the OGGB systems. Global warming potential per dry crop yield was the least for the MAXC system and the most for OGGB system. This suggests management practices designed to reduce global warming potential can be achieved without a loss of productivity. For example, MAXC systems over time may provide sufficient soil C sequestration to offset associated greenhouse gas emission.     

The global greenhouse effect

The global warming caused by emissions of CO₂ and trace gases is expected to cause shifts in climatic zones and rainfall patterns, and possibly thermal expansion of oceans. There are likely to be impacts on global agriculture and the food security of low-income countries, as well as disruptions to major ecosystem complexes such as forests. Rising sea levels will threaten low-lying regions, coastal zones and islands. Policy-makers will therefore have to consider the relative costs and benefits of 'doing nothing', preventive measures and adaptive responses. Economics should play a key and innovative role in this analysis.     

Are there limits to growth? The need for a transition to a solar-based economy

The idea of limits to growth has, understandably, achieved notoriety since the days of Malthus and, more recently, the Club of Rome. However, there must be some limits to the ability of the earth to sustain a growing population. Fortunately, population models suggest that the world's population will probably level out at about two to three times the present numbers over the next hundred years. The question is whether the earth's resources are sufficient to sustain that population at a high standard of living for all. In this the key issue is energy. It is clear that present trends in energy consumption, especially oil, cannot be sustained much longer. Regardless of this, however, prudence demands a drastic reduction in fossil fuel consumption, in view of the possibility of global warming. It can be shown that, combined with greatly improved energy efficiency, a transition to a solar (renewable) energy based economy, capable of sustaining the anticipated growth in the world economy, is possible, but the constraints are extremely tight .     

Global Warming and Global Dioxide Emission: An Empirical Study

In this paper, the dynamic relationship between global surface temperature (global warming) and global carbon dioxide emission (CO₂) is modelled and analyzed by causality and spectral analysis in the time domain and frequency domain, respectively. Historical data of global CO₂emission and global surface temperature anomalies over 129 years from 1860–1988 are used in this study. The causal relationship between the two phenomena is first examined using the Sim and Granger causality test in the time domain after the data series are filtered by ARIMA models. The Granger causal relationship is further scrutinized and confirmed by cross-spectral and multichannel spectral analysis in the frequency domain. The evidence found from both analyses proves that there is a positive causal relationship between the two variables. The time domain analysis suggests that Granger causality exists between global surface temperature and global CO₂emission. Further, CO₂emission causes the change in temperature. The conclusions are further confirmed by the frequency domain analysis, which indicates that the increase in CO₂emission causes climate warming because a high coherence exists between the two variables. Furthermore, it is proved that climate changes happen after an increase in CO₂emission, which confirms that the increase in CO₂emission does cause global warming.     

The role of electricity in sustainable development

Current projections estimating world population growth read in conjunction with corresponding projections of increased world energy consumption, point to electricity as the cleaner fuel of the future, especially because of its high efficiency and low levels of pollution. Due mostly to the fact that the electrical end-use devices are considerably more efficient than those using other forms of energy, most developed countries show decreasing curves of energy intensity as technologies become more sophisticated and shift over to increased reliance on electricity. It is therefore argued in this article that a gradual shift away from fossil fuels to electricity is a promising possibility to bring down global air pollution and emissions of greenhouse gases to acceptable levels. Examples are given of greater efficiency achieved by electrification. Overall gains in energy efficiency from the change over from fossil fuels to electricity, are possible even in situations where the electricity is generated by fossil fuel combustion, despite the loss of primary energy in the conversion process. The article also presents electricity generating projects designed for developing countries and countries with economies in transition. The generation of electricity from the combustion of renewable sources (biomass waste), fossil fuels, and other innovative methods are outlined.     

Green energy for the battlefield

Population of the world is growing with increasing rate and it seems that existing fossil fuel energy sources will not be able to meet energy demand in the near future. Energy is not only crucial for civil sector but also it is one of the most important assets in defense sector. Energy for military operations is mostly provided from fossil fuel as it is the case in other sectors; however, fossil fuels have hazardous effects to the environment and cause global environment concerns. These drawbacks of fossil fuels are also valid for battlefield. Furthermore, transportation of fossil fuels causes extra safety and logistics problems in military case. In this study, we developed a hybrid green energy solution with wind, solar, and batteries together to minimize or eliminate the fossil fuel demand for the battlefield. Results of our algorithm are superior to the already used diesel generator solution from the point of view of cost and various other aspects. The novelty of our study stems from applying optimization of hybrid green energy solution to military case with battlefield constraints.