Carbon Dioxide Equivalent Emissions Research Articles

Determinación de emisiones GEI en una matriz energética sustentable mediante análisis de escenarios

Se toma por Caso de estudio una Matriz Energética Sustentable, compuesta en un 85% por recursos energéticos renovables de origen hidroeléctrico, a fin de estimar las emisiones de dióxido de carbono equivalente (CO2eq; GEI) por MWh de energía consumida y Per Cápita. Antecedentes indican que dicha matriz se abastece con frecuencia de una matriz convencional nacional. La prueba de hipótesis confirma este supuesto; la Matriz Energética Sustentable cubre la demanda energética en un 17% de las veces. Se determina el coeficiente de variación para realizar un análisis de escenarios, a fin de observar el comportamiento de las emisiones de CO2eq/Per Cápita según la participación de la Matriz Energética Sustentable, en ocasiones en las cuales no cubre la demanda y debe proveerse con recursos fósiles del Sistema Interconectado Nacional. Se concluye que el nivel medio de emisiones GEI en un 83% de las ocasiones crece hasta cinco veces que el estimado por unidad de energía (0,10 CO2eq/MWh) y hasta ocho veces por usuario (5,20 tnCO2eq/Per Cápita). Esta conclusión alerta sobre los resultados contradictorios en la operación de las matrices energéticas, diversificadas en la búsqueda de una mayor sustentabilidad ambiental.

The emission reduction potentials of First Generation Electric Aircraft (FGEA) in Finland

Under the looming climate crisis, aviation needs to find new solutions to cut its greenhouse gas emissions. One pathway towards zero emissions is the use of electric aircraft. While current battery technology will not allow for medium and long-haul flights at full capacity, on short-haul routes First Generation Electric Aircraft (FGEA) could play a significant role in the near future. Current FGEA under development could carry 9–19 passengers on distances of 400–1046 km by 2025. This study focuses on the emissions reduction potentials of FGEA in Finland. It compares the carbon dioxide equivalent (CO2-eq) emissions and real travel times (RTT) from door-to-door of FGEA on 47 routes with existing aircraft, train and car transport modes, as well as with proposed high-speed rail (HSR) and electric vehicle implementation. The study found that replacing all existing aircraft with FGEA can clearly be recommended as it would result in a reduction of CO2-eq emissions and RTT. Existing cars should only be replaced by FGEA on routes beyond 170 km. The replacement of existing trains by FGEA under the current energy mix is not recommended. However, once electricity could be provided from renewable energy sources exclusively, it would become feasible to replace existing trains on distances beyond 170 km and HSR beyond 400 km with FGEA.

The carbon footprint of pathology testing.

To estimate the carbon footprint of five common hospital pathology tests: full blood examination; urea and electrolyte levels; coagulation profile; C-reactive protein concentration; and arterial blood gases. Prospective life cycle assessment of five pathology tests in two university-affiliated health services in Melbourne. We included all consumables and associated waste for venepuncture and laboratory analyses, and electricity and water use for laboratory analyses. Greenhouse gas footprint, measured in carbon dioxide equivalent (CO2 e) emissions. CO2 e emissions for haematology tests were 82g/test (95% CI, 73-91g/test) for coagulation profile and 116g/test (95% CI, 101-135g/test) for full blood examination. CO2 e emissions for biochemical tests were 0.5g/test CO2 e (95% CI, 0.4-0.6g/test) for C-reactive protein (low because typically ordered with urea and electrolyte assessment), 49g/test (95% CI, 45-53g/test) for arterial blood gas assessment, and 99g/test (95% CI, 84-113g/test) for urea and electrolyte assessment. Most CO2 e emissions were associated with sample collection (range, 60% for full blood examination to 95% for coagulation profile); emissions attributable to laboratory reagents and power use were much smaller. The carbon footprint of common pathology tests was dominated by those of sample collection and phlebotomy. Although the carbon footprints were small, millions of tests are performed each year in Australia, and reducing unnecessary testing will be the most effective approach to reducing the carbon footprint of pathology. Together with the detrimental health and economic effects of unnecessary testing, our environmental findings should further motivate clinicians to test wisely.

A two-stage multi-criteria analysis method for planning renewable energy use and carbon saving

Renewable energy use is critical for achieving climate change goals. It is essential to understand necessary to the priority, capacity, and number of units of renewable energy systems for generation planning. Multi-criteria analysis methods serve as an effective tool for planning renewable energy generation. In this work, a two-stage multi-criteria analysis method was developed to identify the priority and capacities, as well as the numbers of units of renewable energy technologies. Technical (capacity factor and power density), economic (benefit-to-cost ratio), and environmental (carbon dioxide equivalent emission) criteria were considered. The method was applied to plan Glasgow’s renewable energy use. It was found that the planned renewable energy use configuration consists of 255 units of wind turbines (3.6 MW each), 23,497 units of solar photovoltaic panels (11 kW each), 2 units of biomass combustion systems (2 MW each), and 3382 units of ground source heat pumps (22.5 kW each) corresponding to an annual carbon footprint of 109,629 tonnes carbon dioxide equivalent. Sensitivity analysis was also conducted to assess the impacts of weightings in technical, economic, and environmental criteria on the decision in the configuration of renewable energy use.

Effective diabetes complication management is a step toward a carbon-efficient planet: an economic modeling study

BackgroundThe management of diabetes-related complications accounts for a large share of total carbon dioxide equivalent (CO2e) emissions. We assessed whether improving diabetes control in people with type 2 diabetes reduces...

A new example of circular economy: Waste vegetable oil for cogeneration in wastewater treatment plants

Waste vegetable oil is generated from different sources, such as domestic, commercial and industrial activities, and it requires proper management. Due to the increase in the generation of waste vegetable oil, concern for its management has intensified.The most common management option for waste vegetable oil is the conversion into biodiesel, which improves the chemical-physical characteristics of raw waste vegetable oil for its use but is characterized by significant energy consumption and environmental impact. Therefore, straight waste vegetable oil as fuel, after mechanical pre-treatments and with suitable operational strategy, is suggested in the available literature.In this work, waste vegetable oil from the separate collection is proposed as a source to fuel a combined heat and power unit producing energy for wastewater and sludge treatment plants, which is high energy-demanding.The operation of the combined heat and power unit is analyzed considering data from an experimental campaign carried out to investigate the performance of internal combustion engines powered by waste vegetable oil. Such experimental data are used to carry out the feasibility analysis of a combined heat and power system for an actual wastewater treatment plant located in the Campania region, southern Italy.The system appears to be economically feasible with a simple payback around 3.44 years, a net present value higher than 19.0 M€ and an interest rate of return of 26.7%. Moreover, it produces 70.0% less equivalent carbon dioxide emissions, with respect to a similar system powered by fossil fuels.Therefore, waste vegetable oil as a locally available and renewable energy source may contribute to realize smart and resilient communities, since it improves securing domestic energy supply and waste valorization.

Comparing greenhouse gas emissions associated with food away from home versus food at home in the United States

Food consumption patterns continue to shift away from food at home (FAH) to food away from home (FAFH), and the prevalence of FAFH is significant in the developed world, so the comparative greenhouse gas emissions (GHGE) of FAH and FAFH are predicted in this study. The GHGE per mass of food acquisition in the U.S. is predicted to be 4.3 kg of carbon dioxide equivalent emissions (CO2e)/kg food and 2.7 kg CO2e/kg food for FAFH and FAH, respectively, which is attributed to higher chicken and beef consumption in FAFH. Predictions also suggest that 23% of total food acquisition by mass is by FAFH, with nearly half of the FAFH consumption in the form of beverages. FAFH was predicted to account for 33% of total food GHGE, which is nearly identical to the portion of daily energy intake by FAFH, and both FAFH and FAH meals are estimated to have a nearly constant value of 1.3 g CO2e/kcal. FAFH meals are shown to be, on average, 330% higher in cost, 60% higher in GHGE, and 70% higher in energy content than FAH meals by mass. FAFH meals are also predicted to be higher in GHGE per mass than the 2,000 calorie USDA recommended diet. The larger relative cost compared to relative GHGE suggests that the financial burden of shifting to FAFH mitigates the growth in GHGE attributed to the overall food system.

Seasonal and diurnal variations of greenhouse gas emissions from a saline mangrove constructed wetland by using an in situ continuous GHG monitoring system.

Wetland systems play important roles in the issues of global warming. That is because wetlands can not only intake carbon and nitrogen in the plants and sediments, but could also release carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) to the atmosphere during the microbial decomposition processes in the water. In the past, greenhouse gases (GHGs) were measured mostly by using the manual sampling technique; however, it is difficult to measure the diurnal variation of greenhouse gas emissions. In this study, a floating chamber used to collect GHGs, which were then in-site monitored with a continuous GHG analyzer, through a Teflon tube connected to the top of the chamber was designed. The data for seasonal and diurnal variations of GHGs, emission fluxes of GHGs, and equivalent carbon dioxide emissions (CO2-e) were measured to explore the extent of a saline mangrove constructed wetland contributing to global warming. In addition, the correlation and regression analysis among greenhouse gas emissions, water quality, and other environmental factors were analyzed statistically. The results of continuous monitoring of GHGs showed that the concentrations of CO2 emitted from a saline mangrove constructed wetland ranged from 383.5 ± 25.9 to 476.8 ± 24.2ppm. The diurnal variation of GHG concentrations was significant, which showed that the GHG concentrations in the daytime were generally lower than those at nighttime. The emissions of methane (CH4) from the wetland were monitored in a range between 3.7 ± 1.4 and 28.6 ± 7.6ppm, while the concentrations of nitrous oxide (N2O) emitted from the wetlands ranged from 3.1 ± 2.6 to 0.9 ± 0.6ppm. Hence, the diurnal variations of CH4 and N2O concentrations showed higher values in the daytime than those at nighttime. The correlation analytical results among GHG emissions, water quality, and other environmental factors presented that the emission fluxes of CO2 and BOD5 were positively correlated, but a negative correlation was shown for global solar radiation (GSR). Moreover, the concentrations of CH4 and N2O had moderately positive correlation with both air temperature and water temperature.

Emission profile of Pakistan’s agriculture: past trends and future projections

Reducing greenhouse gas (GHG) emissions is a global concern after Paris Agreement (PA). Identification of GHG emission sources and accurate and precise estimation of the corresponding emissions is the first step to meet reduction targets under PA. Increasing share of agricultural emissions in the global concentration has raised concerns on this sector. Now, reducing agricultural emissions without compromising food security is a real challenge. The present study was aimed to provide the current emission profile of Pakistan’s agriculture, historical emission trends and future projections under agricultural growth scenarios according to prescribed guidelines of Intergovernmental Panel on Climate Change (IPCC) for national GHGs inventory development. In this study, GHG emissions were estimated using United Nations Framework Convention on Climate Change (UNFCCC) Non-Annex-I Inventory Software (NAIIS), version 1.3.2 as per prescribed Revised 1996 IPCC Guidelines. In these emission estimations, tier-1 approach (which employs default emission factors) was used in accordance with national circumstances and data availability in the country. The emissions baseline was projected for 2030 under business as usual (BAU), food security (FS) and enhanced consumption pattern (ECP) scenarios. Agriculture sector emitted 174.6 million tons (Mt) of carbon dioxide equivalent (CO2-equivalent) emissions, of which 89.8 Mt is methane (CH4) and 83.7 Mt is nitrous oxide (N2O). Carbon monoxide (CO) emissions were found to be 1.07 Mt of CO2-equivalent. Emission from agricultural soils constituted 45.5% of the total agricultural emissions followed by 45.1% from enteric fermentation and 6.5% from livestock manure management. The rest of 1.7% of the emissions were from rice cultivation followed by 1.1% from burning of crop residue. Historical emission trends showed that the agricultural emissions grew from 71.6 to 174.6 Mt of CO2-equivalent from 1994 to 2015, a 143.8% increase over the period of 21 years. Emissions baseline projections were found to be 271.9, 314.3 and 362.9 Mt tons of CO2-equivalent under BAU, FS and ECP scenarios, respectively.

SECTORAL CONTRIBUTIONS TO CARBON DIOXIDE EQUIVALENT EMISSIONS IN THE NIGERIAN ECONOMY

In line with the Intergovernmental Panel on Climate Change (IPCC), we estimate the percentage carbon dioxide equivalent (CO2-eq) emissions by sector in Nigeria. In terms of its emissions, the percentage contribution of carbon dioxide, CH4 and N2O to each sector were considered using the 2006 IPCC emission calculation default taking 2012 as the base year projected to 2027. Results revealed that, fugitive emissions from oil and gas accounted for the highest contribution to CO2-eq emissions with about 75.27% when compared to other sectors. This is due to increased gas flaring employed to dispose of associated gas in major petroleum/oil producing areas in the country. This sector pollutes because of their technology, the remaining sectors were identified as important sectors because of the weight they have on the economy. The study suggests the need for Nigerian government to ensure the security of fuel source for power generation by mandating oil companies to channel their flared gases to power plant.

Evaluation of potential feedstocks for sustainable biogas production in Ghana: Quantification, energy generation, and CO 2 abatement

This study aimed at evaluating the potential biogas production from four main sources, in terms of the volume of methane for energy production and the equivalent avoidable carbon dioxide emissions ...

A multi-objective approach to the prospective development of the European power system by 2050

This paper reports the recent work carried out to engage both the environmental impact and the economic indicators on the prioritisation of dispatchable technologies in the European energy mix up to 2050. Those two contradictory indicators are incorporated in a multi-criteria optimisation leading to iterations of two scenario: business as usual and 2 °C climate policy. The results present the evolution of the climate change emission versus the operational costs of the power system up to 2050. The yearly electricity mix evaluations allow assessing the long-term development of the European energy system, where a focus is done on variable renewable energy production. It is shown that policy-only solutions, associated with a traditional cost-oriented optimisation, have a limited impact on helping the power sector to reach emission levels targets. Integrating the objective of reducing emissions to the management of power plants would reduce the absolute and cumulative carbon dioxide equivalent emissions. The counterpart is that the system electricity price tends to increase faster thus implying increased social costs.

Carsharing: mitigation strategy for transport-related carbon footprint

Carsharing (CS) plays an important role in environmental improvements and can be managed as a low-carbon transportation innovation to mitigate the transportation-related carbon footprint. By conducting a questionnaire survey regarding people’s willingness to adopt CS, as well as constructing metrological models to estimate the environmental consequences of the People’s Republic of China’s (hereinafter “China”) CS market, we find that environmental consequences are closely associated with the CS market. The present study makes a significant breakthrough in the field by building a bridge between them. Previous studies only estimated the environmental impact of CS independently. Analysis shows that a high level of people’s acceptance of CS predetermines the market trend and its continuity. Environmental benefits increase with market size. Results suggest that in 2017 alone, 1.69 × 109 million joules ( MJ) of energy savings and an equivalent carbon dioxide (CO2) emission reduction of 13,6000 tons were due to China’s CS market. During the same period, China’s CS market size increased from 430 million Renminbi (RMB) in 2016 to 1.729 billion RMB in 2017. A greater magnitude of the impact is predicted in 2020 and 2025, according to an analysis of China’s lasting CS market. The impact of CS on parking land use can be quantified through a metrological model. Notably, this is the first study to build a combined dynamic and static model for estimating the reduced parking demands with regard to land use due to CS. Results suggest that in 2017, 4.68 × 109 square meters (m2) of land use savings was theoretically due to China’s CS market. While previous studies have qualitatively linked reduced vehicle ownership and parking demand, few studies have quantified the magnitude of that impact, and no models have been developed. Such complementarity makes it possible to use multiple methods in a single research program, including a mixture of quantitative and qualitative approaches. While CS originated in Europe and America, numerous studies have examined the environmental impact of CS operations worldwide. Surveys in Europe indicate that per CS user reduces CO2 emissions by 50% and that the local environmental quality has been improved by CS. An estimated annual reduction of 0.58 tons of CO2-equivalent (CO2e) per household member per year was reported in North America due to observed changes in household driving. Analysis shows that mode shifts from public transit or private car usage to CS vehicles result in an average of 146–312 kilograms (kg) of CO2 reduction per member per year in Ulm, Germany, and that employing hybrid vehicles and electric vehicles (EVs) can reduce CO2 emissions by approximately 35% and 65%, respectively, in Lisbon, Portugal. Additionally, CS users reduce transportation-related carbon dioxide emissions by up to 45–55% per household. Results suggest that upon joining a CS organization, current CS members in the United States of America (USA) reduce their average individual transportation energy use and greenhouse gas (GHG) emissions by approximately 51%. With regard to the impact of CS on parking demands, results suggest that overall parking needs are reduced owing to the reduced volume of the vehicles caused by the adoption of CS. Additionally, policy implications affect CS operations greatly. Keen interest from policymakers gives a further boost to CS with regard to parking space and synergies with other mobility modes. Accordingly, recommendations for sustainable improvement of CS’s environmental benefits are as follows: CS systems should complement public transportation, as well as the proliferation of fuel-efficient CS EVs; CS operations should share preferential policies on energy savings and emission reductions; the induction of collateral environmental benefits in the context of intermodal supply, in consideration of the possible rebound effects of CS; the certification of credits for CS environmental impacts. The analysis presented herein is aimed at helping policymakers better appreciate the environmental contributions of the CS market, support the market continuously, and provide a platform for the exchange of experience (e.g., arguably, generalization of China’s CS’s operation pattern characteristic of a large proportion of new EV use in the CS market) and learn from each other in mitigating climate change in the transportation sector. We conclude with a summary of key findings and recommendations for policy formulation and future research.

Automatic structural design by a set-based parametric design method

Modern structural design faces new challenges, such as addressing the needs of several stakeholders and satisfying the criteria for achieving sustainability. The traditional design process does not allow resolution of these challenges. The purpose of this project was to investigate the applicability of a Set-Based Parametric Design method to the structural design process of bridges. The focus was on the early design stage, in which the design team evaluates design alternatives against a chosen set of criteria. The main challenge in this stage of design is that the process should be cost- and time-effective while allowing comparison of the different alternatives and their evaluation in terms of the different design criteria. Certainly, structural design is often performed by a discussion between the different stakeholders involved in this process, i.e. the client, contractor, and engineering team. An evaluation of alternatives against criteria requires a more detailed design, which is contradictory to the early design stage when information is scarce. The selected approach was to develop a script that can generate information for decision-making, automate the structural design process, perform common routine design tasks, and control the numerical analysis. The method combined Set-Based Design, Parametric Design, Finite Element Analysis and Multi-Criteria Decision Analysis. Three existing bridges were selected to demonstrate the applicability of the developed method. The method was successfully applied and it was observed that it resulted in bridges that were more efficient in terms of material costs and carbon dioxide equivalent emissions compared with existing bridges. By delaying the decisions and developing the sets of alternatives, various alternatives can be assessed and evaluated, in the design stage, against different sustainability criteria.

A municipal solid waste indicator for environmental impact: Assessment and identification of best management practices

Abstract The objective of this study was to develop an aggregate indicator to assess the environmental impact of municipal solid waste management in the small municipalities of the state of Sao Paulo, Brazil. Additionally, the study aimed at creating a classification of the municipalities considered to identify the best management practices. The study consisted of five phases: Phase 1: Selection of municipalities; Phase 2: Data collection (inputs); Phase 3: Use of the Waste Reduction Model; Phase 4: Analysis of results (outputs) and; Phase 5: Construction of the aggregate indicator and comparison between municipalities to analyze management practices. The results showed that the average waste generation was 223.89 kg (inhabitant−1 year−1), the average carbon dioxide equivalent (CO2e) emissions was 0.166 tons (inhabitant−1 year−1), the average amount of energy savings was 51.37 kWh (inhabitant−1 year−1) and that most municipalities had suitable final waste destinations. After developing the aggregate indicator, which was a geometric mean of the normalized indicators for waste generation, emissions of CO2e, energy consumption and quality of final destination, the municipalities were ranked. Among the ten best-ranked municipalities, six of them disposed of the waste in municipal landfills, and four, in private landfills. Only one municipality is part of a consortium, while seven of them have institutionalized selective collection. One of the critical points for good indicators is the presence of waste pickers. For further improvements in the management of these municipalities, it is suggested that practices involving recycling and the integration of waste pickers with proper technical training are developed and implemented further. It is also recommended fostering greater social inclusion and integrated participation in the management of municipal solid waste. The aggregate indicator developed was regarded as appropriate to assess the environmental impact of municipalities and to classify them, allowing the identification of the best management practices.

Effective climate change mitigation through cover cropping and integrated fertilization: A global warming potential assessment from a 10-year field experiment

Abstract In this study, field-specific data was collected from a 10-year experiment in central Spain in which vetch (Vicia sp. L.) and barley (Hordeum vulgare L.) were established as cover crops and compared to the traditional fall-winter fallow between two irrigated cash crops, maize (Zea mays L.) and sunflower (Helianthus annuus L.). The global warming potential (GWP) balance included direct and indirect (nitrous oxide (N2O) resulting from the deposition of ammonia (NH3) or from leached nitrate (NO3−)) soil greenhouse gas (GHG) emissions, changes in soil organic carbon (SOC) and albedo, and carbon dioxide equivalent (CO2eq) emissions from inputs, irrigation and farm operations. Several scenarios involving i) changes in the termination method of the cover crops, ii) consideration of the application of a distinct nitrogen (N) source (urea, slurry or manure instead of ammonium nitrate) or nitrification inhibitors, iii) employing the same N rate for all treatments (i.e., conventional instead of integrated fertilization), iv) modelling SOC accumulation over a 100-year horizon, and v) using default emission factors, were also analysed. Under the conditions of our experiment, cover crops mitigated yield-scaled emissions by 77.4% (barley) and 91.9% (vetch). Synthetic N fertilization (particularly the industrial production of fertilizer) contributed 38% to the balance of the cover cropping treatments, followed by SOC (22.5%), irrigation (14.7%) and albedo (14.5%). All scenarios led to notable mitigation efficacies, ranging from 39% mitigation (in barley when considering default or non-specific emission factors) to a net CO2eq sink (i.e., >100% mitigation) in the scenario consisting of the replacement of ammonium nitrate by urea or organic fertilizers although with side effects on NH3 volatilization and/or yields. Based on these results, the combined use of cover cropping and integrated soil fertility management could lead to the design of C-neutral irrigated cropping systems in semi-arid regions.

Impact of seasonal thermal energy storage design on the dynamic performance of a solar heating system serving a small-scale Italian district composed of residential and school buildings

Abstract A centralized solar hybrid heating system serving a small-scale district composed of 6 typical Italian residential buildings and 3 schools located in Naples (southern Italy) has been modelled, simulated and analysed by means of the dynamic software TRNSYS over a 5-year period. The plant is based on the operation of solar thermal collectors connected to a seasonal double U-pipe vertical Borehole Thermal Energy Storage (BTES) in order to address the seasonal misalignment between solar energy supply and thermal energy demand for heating purposes. In this paper a parametric analysis has been performed in order to investigate the performance of the district heating network upon varying the characteristics of the BTES in terms of: (i) thermal conductivity of soil, (ii) thermal conductivity of grout, (iii) U-pipe spacing, (iv) heat carrier fluid, (v) number of Borehole Heat Exchangers (BHEs), as well as (vi) type of BHEs connection (series, parallel or mixed). The primary energy consumption, the equivalent carbon dioxide emissions and the operating costs of the proposed district heating plant have been evaluated based on the simulation results upon varying the plant configurations and then compared with those associated to a conventional Italian decentralized heating system assumed as reference with the main aims of (i) assessing the potential reduction of primary energy consumption, global CO2 equivalent emissions and operating costs, (ii) exploring the influence of BTES characteristics on the overall system performance as well as (iii) establishing some simple rules for the initial design of BTES.

Mitigation of CO2e Emissions from the Municipal Solid Waste Sector in the Kingdom of Bahrain

Mitigating climate change to limit the global temperature increase (relative to pre-industrial temperatures) to 2 °C is receiving considerable attention around the world. Here, historical and future carbon dioxide equivalent (CO2e) emissions from municipal solid waste (MSW) in Bahrain were calculated using the revised Intergovernmental Panel on Climate Change (IPCC) 1996 and IPCC 2006 methods. The extent to which waste-to-energy (WtE) technologies can contribute to climate change mitigation was assessed by performing a multicriteria analysis. The results indicated that CO2e emissions from MSW in Bahrain have been increasing since the Askar landfill was constructed in 1986. Emission recalculations indicated that CO2e emissions from MSW contribute 6.2% of total emissions in Bahrain rather than the 11.6% reported in the second national communication. Methane emissions from MSW in 2030 are predicted to be 22–63 Gg. The WtE technologies anaerobic digestion and landfill gas recovery gave the best and gasification the worst multicriteria analysis model results. A database of WtE plants around the world should be compiled to allow decisions around the world to be based on best practices. The potential for maximizing energy recovery and decreasing costs needs to be investigated to allow WtE plants to compete better with renewable and nonrenewable energy sources.

Sustainability assessment of crop production in accord with energy, environment and economic performances in Nepal

Increasing crop production usually warrants increased use of energy in the system that triggers the question of locating an ‘appropriate’ operating point by weighing the economics of output and its environmental impacts. Sustainability of diverse cereals, legumes and vegetable production systems were assessed in lowlands of Nepal in light of the efficiency of energy use, CO2e (carbon dioxide equivalent) emissions and financial return–cost ratios. The energy saving potential of 238 farms selected in the study area is calculated adopting Data Envelopment Analysis (DEA). Based on the per-hectare energy consumption, vegetables (12.37 GJ), cereals (10.60 GJ) and legumes (3.80 GJ) crop production systems are ranked in descending order. Rice offered the highest per-hectare energy output (68.99 GJ) among the selected crops. Potential saving of energy inputs in the study area is shown to be between 18 and 35% without conceding yield of the particular crop production system. The highest environmental impact is due to garlic production (2997.13 kg CO2e ha−1); while rice, maize, wheat, lentil, mungbean and onion crops emit 60, 63, 28, 5, 3 and 86% CO2e emissions (of that of garlic crop), respectively. As expected, the vegetable production remains the most profitable system with the return–cost ratio of 2.96–3.52, followed by legume (1.83–2.16) and cereal (1.21–1.96) production systems.

Short Run Effects of Carbon Policy on U.S. Electricity Markets

This paper presents estimates of short run impacts of a carbon price on the electricity industry using a cost-minimizing mathematical model of the U.S. market. Prices of $25 and $50 per ton of carbon dioxide equivalent emissions cause electricity emissions reductions of 17% and 22% from present levels, respectively. This suggests significant electricity sector emissions reductions can be achieved quickly from a modest carbon tax, and diminishing reductions occur when increasing from $25 to $50. The model captures short run effects via operational changes at existing U.S. power plants, mostly by switching production from coal to natural gas. A state-level analysis yields the following conclusions: (1) states which reduce the most emissions are high coal-consumers in the Mid-Atlantic and Midwest regions, (2) 15 states increase emissions after carbon policy because they increase natural gas consumption to offset coal consumption decreases in neighboring states, and (3) a flat per-capita rebate of tax revenue leads to wealth transfers across states.