Increased Energy Use Research Articles

Balancing environmental impacts and economic benefits of agriculture under the climate change through an integrated optimization system

The present study proposes a framework to mitigate impact of climate change on the rice production by maximizing the yield while the energy use and ecological impacts on the river ecosystem as the irrigation source are mitigated. Coupled general circulation model- soil and water assessment tool (SWAT) was utilized to project the impact of climate change on the stream flow. Fuzzy physical habitat simulation was applied to develop the ecological impact function of the river. Moreover, a data-driven model was developed to predict the rice yield through changing water and energy consumption. Finally, all the simulations were utilized in the structure of the optimization model in which minimizing loss of the production, greenhouse gas emission by reducing energy use and physical habitat loss were considered as the objectives. Based on the results, the Nash–Sutcliffe model efficiency coefficient of the SWAT is 0.7 that demonstrates its reliability for simulating the impact of climate change on river flow. The optimization model is able to reduce the impact of climate change on yield of production by balancing water and energy use. In the most pessimistic scenario, water use should approximately be reduced 25% for protecting river ecosystem. However, the optimization model approximately increased energy use 16% for preserving the yield of the rice. Conversely, model decreased the energy use 40% compared with the current condition due to increasing water supply. Moreover, physical habitat loss is less than 50% that means the combined optimization model is able to protect river habitats properly.

Design of a Lifecycle-Oriented Environmental and Economic Indicators Framework for the Mechanical Manufacturing Industry

As a result of the worldwide depletion of natural resources, increased energy use, and environmental, economic, and social imbalance, organizations are working to identify the proper strategies supporting the continuous reduction of their impacts. While this trend is fundamentally agreed upon in the literature, several manufacturing industries still fail to identify which elements most influence their contributions to the impact of sustainability and how to easily manage the calculation of these effects within a manufacturing system. The purpose of this article is to incorporate sustainability practices into manufacturing by developing a set of key performance indicators (KPIs) for assessing and improving environmental and economic management practices at the corporate and production level. The definition of the framework began with in-depth research of the leading indicators and framework types in the literature, integrating the most exploited industrial standards to make them easily acceptable in the industrial domain. Then, to provide a broad view of company behavior, the framework has been designed to take either an inventory and impact point of view, thus providing indicators for the online monitoring of the company operations, or assessing their impacts in an LCA-LCC perspective. In selecting the indicators and the definition of the framework structure, five industrial cases covering different business sectors were involved in identifying the most critical indicators in terms of calculability and defining a structure that would allow for their application in various business situations. Therefore, the defined framework has been validated at a conceptual level, thus laying the basis for future quantitative validation. Twenty key performance indicators (KPIs) for assessing the sustainability of manufacturing firms have been created based on the 163 indicators studied.

Energetics and profitability of peanut (Arachis hypogaea)-based cropping systems as influenced with conservation agricultural practices

Increasing energy use efficiency and reducing greenhouse gases (GHGs) emissions from agriculture are majorchallenges to achieve sustainable development goals (SDGs). An experiment, comprising 14 treatments, viz. sole peanut (Arachis hypogaea L.), peanut-fallow-sesbania, peanut-fallow-green gram (GG), peanut-conventional tilled wheat (CTW), peanut-CTW-sesbania, peanut-CTW-GG, peanut-CTW-wheat straw incorporation (WSI), peanut-zero tilled wheat (ZTW), peanut-ZTW-sesbania, peanut-ZTW-GG, peanut-ZTW-WSI, peanut+pigeonpea, peanut+pigeonpeasesbania and peanut+pigeonpea-GG was laid out in randomized block design with three replications for five consecutive years (2011–12 to 2015–16) at Junagadh, Gujarat, at fixed site to study the influence of conservation agricultural practices on energetics and profitability of peanut-based cropping systems. Green manuring with sesbania significantly improved the pod yield of peanut (12.8%) and seed yield of pigeonpea (8.9%). Zero tillage (ZT) improved wheat yield by 4.8% over Conventional tillage (CT). The energy requirement of peanut+pigeonpea intercropping was 16.7% lower than peanut–wheat cropping system irrespective of GM and WSI. Peanut–ZT wheat with sesbania green manure recorded highest energy output (251.2 × 103 MJ/ha) and net energy (201.0 × 103 MJ/ha). This cropping system also fetched the highest system productivity (4551 kg/ha), and system profitability (` 125.7 × 103/ha) followed by peanut–ZT wheat (INR 120.6/ha × 103/ha). Therefore, peanut–ZT wheat–green manuring (sesbania/greengram) cropping system was found as productive, economical and energy efficient which might be promoted to intensify the sole peanut cropping in Saurashtra region of Gujarat.

COVID-19 pandemic ramifications on residential Smart homes energy use load profiles

The COVID-19 pandemic has significantly affected people’s behavioral patterns and schedules because of stay-at-home orders and a reduction of social interactions. Therefore, the shape of electrical loads associated with residential buildings has also changed. In this paper, we quantify the changes and perform a detailed analysis on how the load shapes have changed, and we make potential recommendations for utilities to handle peak load and demand response. Our analysis incorporates data from before and after the onset of the COVID-19 pandemic, from an Alabama Power Smart Neighborhood with energy-efficient/smart devices, using around 40 advanced metering infrastructure data points. This paper highlights the energy usage pattern changes between weekdays and weekends pre– and post–COVID-19 pandemic times. The weekend usage patterns look similar pre– and post–COVID-19 pandemic, but weekday patterns show significant changes. We also compare energy use of the Smart Neighborhood with a traditional neighborhood to better understand how energy-efficient/smart devices can provide energy savings, especially because of increased work-from-home situations. HVAC and water heating remain the largest consumers of electricity in residential homes, and our findings indicate an even further increase in energy use by these systems.

Simultaneous Reduction of Thermal Stratification and Ammonia Concentrations in Poultry House During Brooding and in Cool Weather

HighlightsPen-scale system eliminated thermal stratification while full-scale system reduced thermal stratificationPen-scale system was moderately effective in trapping ammonia and reduced pen ammonia concentrations modestlyAmmonia trapping performance was mainly affected by dust build-upDust build-up was partly mitigated by a shakerCitric acid coated burlap placed upstream of livestock barn exhaust fans may reduce ammonia and dust emissionsAbstract. High ammonia (NH3) concentrations during poultry brooding can reduce bird performance and welfare. Thermal stratification during brooding can increase energy use and reduce bird welfare. A proof-of-concept heat recovery and NH3 control (HRAC) system consisting of a low-cost NH3 filter consisting of citric acid treated burlap placed upstream of a fan was evaluated for its ability to reduce barn NH3 concentration and thermal stratification. In the lab, 5% citric acid on burlap trapped 13 times more NH3 per unit mass of sorbent than activated carbon reported in the literature. Pen-scale and barn-scale HRAC prototypes using 15% citric acid on burlap eliminated and greatly reduced thermal stratification, respectively. The pen-scale HRAC had significant NH3 removal efficiencies ranging from the 17% to 42% in seven of nine events and compared, to the Control pens (no HRAC), significantly reduced floor [NH3] in two of nine events by 26% and 42%. The pen-scale HRAC also reduced footpad dermatitis at 15 d. Performance of the full-scale HRAC was highly variable. Clogging of the filter with particulate matter reduced airflow rates that was partially mitigated using a shaker. A vertical HRAC with a shaker might improve performance. There is need to investigate the effectiveness of 5% citric acid. The citric acid-treated burlap screen placed upstream of barn exhaust fans could reduce dust and NH3 emissions. Keywords: Breakthrough curve, Burlap, Citric acid, Emissions, Energy use, Footpad dermatitis.

User centred design and energy efficient packaging collection infrastructure supporting circular future lifestyles

The collection and recycling of packaging and life cycle assessments have traditionally been developed from a technical perspective, not including the actors in the chain. How recycling should be done depends on who you ask, and whether you look at the issue from an energy, material, legal or user perspective. FTI, the Packaging and Newspaper Collection organization is responsible for better circularity and collecting these fractions in Sweden’s municipalities. When recyclable materials end up in the wrong place, it causes problems leading to increased energy use in the life cycle. The ongoing project Tjårven, aims to reduce energy use in connection with packaging collection, as well as potential energy gains in the second stage of the packaging life cycle, by redesigning packaging collection from a user centred perspective. To do this, design interventions are developed based on observed and self-reported user behaviour, a literature review of state-of-the-art collection infrastructure and an understanding of the system developed using actor-based LCA methodology. The latter methodology is used to show the energy use in the lifecycle, including the actions of the actors in the chain. The interventions developed will be tested through a case study that will be evaluated to see if it helps to achieve more energy efficient collection infrastructure, allowing for better circularity and therefore more sustainable future lifestyles. The present article presents the first part of the project, summarizing the results from the user centred observations, literature review and initial actor-based LCA model.

Greenhouse gas emissions within the exergoenvironmental assessment of a compact combined cooling, heating and power system

Because of the significant public concern regarding climate change (and global warming), greenhouse gas (GHG) emissions have been successfully employed to communicate environmental impacts. This study develops a life cycle assessment of the equipment and energy flows of a combined cooling, heating and power system, expressing the environmental impacts as GHG emissions. Environmental data was used as input to an exergoenvironmental assessment based on the SPECO methodology. The GHG emissions associated with the consumption of natural gas and grid electricity are 0.258 and 0.227 kg CO2-eq/kWh, respectively. The internal combustion engine is responsible for the highest share of GHG emissions (15.95 kg CO2-eq/h), of which 15.80 kg CO2-eq/h is due to the formation of pollutants and the remainder refers to equipment. From the combined analysis of exergoenvironmental parameters, strategies that increase energy use and decrease irreversibilities should focus on the absorber heat exchanger, the steam generator, and heat recovery unit. Some of the recent energy policy responses to the COVID-19 crisis include the deployment of energy solutions such as combined energy systems, and exergoenvironmental assessments can promote the adoption of these more efficient systems.

Energy burden and air conditioning adoption in New York City under a warming climate

• Adaptation to summer heat can place uneven economic burden across households • Climate change intensifies relative energy costs of air conditioning use • Low income homes see large burden increase in spite of lower thermal load rise Global climate change has increased the need for cooling indoor spaces, leading to a rise in adoption of air conditioning. This adoption, while decreasing health risks, can increase energy use and pose economic burdens in low income households. Here, we estimate the burden associated with cooling, as well as potential extreme heat exposure without it in the largest city in the US, New York using a coupled weather and building energy model, utility pay scales, and household income data from the US Census.Results show uneven distribution of AC economic burden, with lower income neighborhoods experiencing the largest relative costs. High-burden neighborhoods see the largest climate-driven increases in spite of lower enthalpy increases. These neighborhoods also have the most exposure to indoor extreme heat, which may triple by end of century. Energy burden may pose a barrier to AC operation, with estimated cost in the lowest income households reaching up to 6.1% of income for a 100 m 2 dwelling, which could increase to 8% by end of century. We also explore adaptation strategies and quantify their impacts, finding that modifying traditional set points and reflective roofs can reduce energy burden significantly, by up to 20% in the highest burden neighborhoods.

Raising Awareness for Pollution Prevention Measuring Individual Pollution Indicators

The research study aims to assess and raise awareness about pollution at the level of an individual, which would contribute to that individual being more careful and aware of the pollution he does and thus reduce the level of pollution in the future. As part of the project, software for measuring and analyzing the individual environmental footprint will be developed and the target will be the younger generation, students and high school students. All those that have been measured with a smaller environmental footprint and who passed the test and have been trained as part of project seminars and have been appointed ambassadors for environmental protection will receive a certificate. As part of the project, a seminar has been organized for education and to raise awareness about pollution. After all, all the ambassadors have been trained and went to other high schools and there they will hold in the presence of their mentors and the lectures about their experiences and awareness-raising and what are the benefits and show them how to use the online calculator that has been developed as part of the project. Research on the ecological footprint has been realized as an indicator of pollution and preservation of the environment. The project examines the current situation in issues related to energy management (increased energy use, limited reserves of raw materials, global warming, etc.). The findings discuss the results and recommendations are provided.

How and why did fossil fuel use change in Fukushima Prefecture before and after the Great East Japan Earthquake?

The Great East Japan Earthquake (GEJE) in March 2011 greatly changed the spatial pattern of energy use in Fukushima Prefecture. The previously nuclear-reliant energy policy has transformed, with energy now generated mainly by fossil fuels and renewable sources. The spatio-temporal variation of fossil fuel use and the major causes of these changes have not previously been fully clarified.This study quantified the annual fossil fuel use in eight user sectors at high spatial resolution using a bottom-up approach. The total fossil fuel use in Fukushima is estimated to have increased by about 91,233 TJ from 2010 to 2015, despite decreases in most socioeconomic indicators. The increase was mainly attributed to changes in electricity generation (104,521 TJ). The three sectors with the greatest decrease in energy use were road transportation (-7159 TJ), industrial and commercial (-3608 TJ), and residential (-2334 TJ). Spatial analysis using high-resolution maps identified areas of increased energy use mainly in central, southeastern, and northeastern Fukushima and confirmed some local variations in energy use by sector. It showed that decreasing energy use in the area within 20 km of the Fukushima Daiichi Nuclear Power Station resulted in increased use in areas located >20 km from the power station. Sensitivity analysis clarified the relations among factors underlying each sector’s changing energy use before and after the GEJE. For instance, consider the electricity generation sector: reduced energy use was caused by decreased energy use intensity (-23,299 TJ) and the increased use of biomass (-4848 TJ), whereas increases were caused by rising utilization efficiency (102,410 TJ) and increased electricity generation capacity (35,988 TJ), which led to a large overall increase for this sector (104,521 TJ). However, road transportation’s negative energy use change (-7159 TJ) arose owing to decreased traffic volumes (-7573 TJ) and decreased energy use intensity (-7177 TJ), despite some positive energy use changes caused by the increased proportion of large vehicles (3684 TJ) and changes in mean travel speed (1381 TJ). The approach used in this study will be helpful for policy makers to evaluate spatio-temporal variations and develop policies to reduce energy use in response to unusual local events.

Characteristics of Bioethanol from Musa Salaccensis ZOLL

The high increase in energy use causes renewable energy solutions such as wind energy, geothermal energy, biomass and others. Biomass is one solution for Indonesia to obtain energy, because Indonesia has the potential for biomass, both biodiesel and bioethanol. The biomass to be studied is Bioethanol. Forest banana is a type of wild plant that grows in the forests of North Kalimantan and is not consumed by residents because there are many seeds in the banana. The purpose of this study was to examine the characteristics of bioethanol from forest bananas. The stages of the research method that will be carried out include several stages, namely 1) making bioethanol, 2) measuring ethanol content, and 3) testing the characteristics of bioethanol. The stages of bioethanol testing carried out characteristic tests including: 1) Ethanol Content Analysis, 2) Moisture Content Analysis, 3) Density Analysis, 4) Specific Gravity and API Gravity Analysis, 5) Calorific Value Analysis. Based on the research results obtained, the quality of the bioethanol produced has a density value and specific gravity in accordance with the bioethanol quality standard, which is 0.46. The calorific value which has a close relationship with API Gravity is close to the maximum value in the bioethanol quality standard, which is 3702.30 kcal/kg. The value of ethanol content and water content still does not meet the quality standards, namely 24.8% and 86%. This is due to the lack of distillation process in this study.

Characteristics of Bioethanol from Musa Salaccensis ZOLL

The high increase in energy use causes renewable energy solutions such as wind energy, geothermal energy, biomass and others. Biomass is one solution for Indonesia to obtain energy, because Indonesia has the potential for biomass, both biodiesel and bioethanol. The biomass to be studied is Bioethanol. Forest banana is a type of wild plant that grows in the forests of North Kalimantan and is not consumed by residents because there are many seeds in the banana. The purpose of this study was to examine the characteristics of bioethanol from forest bananas. The stages of the research method that will be carried out include several stages, namely 1) making bioethanol, 2) measuring ethanol content, and 3) testing the characteristics of bioethanol. The stages of bioethanol testing carried out characteristic tests including: 1) Ethanol Content Analysis, 2) Moisture Content Analysis, 3) Density Analysis, 4) Specific Gravity and API Gravity Analysis, 5) Calorific Value Analysis. Based on the research results obtained, the quality of the bioethanol produced has a density value and specific gravity in accordance with the bioethanol quality standard, which is 0.46. The calorific value which has a close relationship with API Gravity is close to the maximum value in the bioethanol quality standard, which is 3702.30 kcal/kg. The value of ethanol content and water content still does not meet the quality standards, namely 24.8% and 86%. This is due to the lack of distillation process in this study.

The role of climate change and decentralization in urban water services: A dynamic energy-water nexus analysis

Urban water services, including drinking water supply and wastewater treatment, are highly energy dependent, contributing to the challenges described under the water-energy nexus. Both future climate change and decentralized water system adoptions can potentially influence the energy use of the urban water services. However, the trend and the extent of such influences have not been well understood. In this study, a modeling framework was developed to quantify both the separate and the combined influences of climate change and decentralization on the life cycle energy use of the urban water cycle, using the City of Boston, MA as a testbed. Two types of household decentralized systems were considered, the greywater recycling (GWR) systems and the rainwater harvesting (RWH) systems. This modeling framework integrates empirical models based on multilinear regression analysis, hydrologic modeling, water balance models, and life cycle assessment to capture the complex interactions among centralized water services, decentralized water system adoptions, and climate parameters for cumulative energy demand (CED) assessment, considering all residential buildings in Boston. It was found that climate change alone will slightly increase the energy use of the centralized systems towards the end of the century, due to the cancelation effect amongst changes in water quality, flow rate, and space and water heating demand. When decentralization is considered alone, we found economically viable decentralized systems may not necessarily produce energy savings. In fact, RWH adoptions may increase energy use. When climate change and decentralization are combined, they will increase the water yield and cost savings of the decentralized systems, while reducing the energy use from the centralized systems. When the centralized systems are further added into the picture, the CED of the entire urban water cycle is projected to increase by 0.9% or 2.3% towards the end of the century under climate change if GWR or RWH systems are adopted by respective cost saving positive buildings.

518 Late-Breaking: Effect of Feedlot Diets on Environmental Emissions from Four Representative U.S. Feedlots and the Beef Production System

Abstract Our objective was to evaluate effects of feedlot dietary management strategies on environmental impacts and net returns of feedlot operations in the United States. Representative feedlots were simulated with the Integrated Farm System Model (IFSM 4.6; USDA-ARS, University Park, PA) to quantify baseline environmental impacts of feedlot production and full US beef cattle production systems. The simulated dietary strategies included: 10% increase in feed efficiency, use of less water intensive forages, 10% increase in byproduct inclusion, 10% improvement in water use efficiency of corn, and steam-flaking of corn. Days on feed and head finished per year were held constant for all strategies to have equal comparisons to baseline results. Dietary management strategies were individually modeled and simulated in IFSM for each feedlot operation to obtain intensities (expressed per kg gain) for greenhouse gas (GHG) emissions, fossil energy use, blue water consumption, and reactive nitrogen loss. Feedlot operations were then linked with cow-calf, stocker, and backgrounding operations to estimate environmental intensities (expressed per kg CW) for full cattle production systems. Improving feed efficiency had the greatest effect on reducing carbon emission intensities (6%), energy use intensity (8%), blue water use intensity (9%), and reactive N loss intensity (4%) for feedlot operations. Increasing corn byproduct inclusion resulted in 9% reduction in blue water use intensity. However, byproduct inclusion increased reactive N loss intensity by 11% as a result of greater protein concentrations in the diet. Switching from rolled corn to steam flaked corn increased energy use intensity by 9%, but little to no changes (1% increase to 3% reduction) were observed for other environmental intensities. Improved feed efficiency was the most effective strategy to reduce environmental footprints of beef cattle production (1 to 2% reductions). Overall, feedlot dietary strategies were less pronounced for the full beef production system compared with feedlot results.

Rebound effect with energy efficiency determinants: a two-stage analysis of residential electricity consumption in Indonesia

This study aims to estimate the economy-wide rebound effect using the determinants of household energy demand in Indonesia. Identifying the size of the rebound effect is essential for the government's energy efficiency and carbon emission reduction programs. The estimation of the rebound effect uses a two-stage analysis with panel data of every province in Indonesia from 2002 to 2018. We employ the Input Demand Function of the Stochastic Frontier Analysis to measure the energy efficiency of residential aggregate in Indonesia. In the second stage, we adopt the dynamic panel data model to estimate the economy-wide rebound effect. The estimated dynamic panel data model reveals that the magnitudes of the short-run and long-run rebound effects were 87.2% and -45.5%, respectively. In other words, a 1% increase in household energy efficiency results in a reduction in energy consumption of 0.13% in the short term and 1.45% in the long term. Our research also discovers that a backfire rebound effect exists in provinces with high energy efficiency. Therefore, we prove to backfire claims that improving energy efficiency will increase energy use. Henceforth, energy efficiency programs in the household sector still need to be implemented, followed by increasing technological innovation and improving housing policy.

Photovoltaics in the built environment: A critical review

In this manuscript we review research on the feedback mechanisms between photovoltaic energy production and the urban environment, with an emphasis on synthesizing what is known, while drawing attention to limitations, and indeed errors in, the literature on this topic.We include in our analysis studies on photovoltaic (PV) systems in urban settings – on buildings, as shade structures, or as stand-alone arrays within an urban environment. We further limit the review to studies that investigate how the urban setting affects the performance of PV systems or how PV systems affect their surrounding urban environment. Our review is based on a systematic search of the literature, which revealed 116 unique articles that addressed the underlying questions in a meaningful way. While there are conflicting results reported across this body of literature, our review and synthesis reveal two key findings: (1) PV can significantly warm the city during the day, provide some cooling at night, and potentially increase energy use for air conditioning of buildings in some climates and building types; and (2) placing PV in an urban setting can adversely affect PV efficiency, reducing overall power production up to 20% in comparison to PV applications in rural settings. It is recommended that future developments of PV technologies focus both on increased efficiency and the need to increase reflection of wavelengths of energy not converted to electricity by the PV cells. Furthermore, designs for urban PV systems should explicitly consider the effects of elevated urban temperatures, pollution, and shading on system performance.

Development of Solar Powered Biodiesel Reactor for Kuwait Sheep Tallow

Biodiesel is one of the more recent green fuel products in the world. It can be produced from several raw materials such as straight vegetable oils, animal fats, tallow, and waste cooking oils, and blended with diesel. Properties of biodiesel are different compared to fossil diesel in terms of production methods and emission levels released after combustion in an internal combustion engine. Kuwait consumes a huge amount of energy which is almost 8% to meet the increasing demand for electricity and water. Moreover, the use of electricity in the production of biodiesel increases energy use and cost of production. Kuwait is receiving an amount of solar irradiation ranging from 2050 kWh/m2 to 2100 kWh/m2. The present study is concerned with the evaluation of the potential to use solar energy to produce biodiesel from sheep fat waste as a raw material. An experimental test rig was set up for a single cylinder diesel engine in the laboratory, where a solar power system was used to assist the production process of biodiesel from tallow waste. The biodiesel is then blended with diesel at different volume percentages, such as graded as B20, B50, B75 and B100, respectively. The exhaust gases such as oxygen, carbon monoxide, carbon dioxide, nitric oxide and nitric dioxide where also analyzed. An optimum decrease in values of nitric oxide levels was observed at the load of 51%, 68%, 85% and 93% during the operation at blend of biodiesel B20, B50, B75 and B100, respectively. Nitric dioxide was decreased at the load of 51%, 68% and 85% during the operation using B20, B50 and B75, respectively. Optimum SFC was achieved at B20, B50 and B75 during high loads of 85% and 93%. It can be concluded that sheep tallow biodiesel shows a promising result in terms of fuel consumption and environmental emissions of greenhouse gases.

Towards a Sustainable Energy Planning Strategy: The Utilisation of Floor Area Ratio for Residential Community Planning and Design in China

Floor Area Ratio, commonly known as FAR, is a primary planning metric in urbanism. It is commonly known as the ratio of accumulated built floor areas against the size of a site/plot. In recent years, China's rapid urban development has resulted in a substantial increase in FAR, particularly in residential areas. A notable shift from low-rise row housing typology to a more common high-rise residential unit is certainly a key factor behind the increase of energy use in many Chinese cities. This factor highlights the need for a sustainable energy planning strategy at the community level. As a novelty, this study reflects on the FAR changes in the context of China, and evaluates the impacts on energy use at the community scale. This study tests four FAR models of 1.0, 2.5, 3.0, and 4.0 and provides a computational modelling analysis, with a comparison analysis. FAR models of 1.0 and 4.0 are typical models of low-rise and mid-to-high rise, respectively. Findings suggest FAR 4.0 as the least efficient for energy planning while FAR 1.0 is the least economically viable model. The results support policy development on FAR monitory, and paradigm shifts for future urban development models, particularly for the small to medium-scale residential compounds in cities.

Energy mix, technological change, and the environment

This paper studies the relationship between the energy mix and the environment using a theoretical framework in which two alternative energy sources are considered: fossil fuels (dirty energy) and renewable energy (clean energy). We find that a positive aggregate productivity shock increases energy consumption and emissions but reduces energy intensity and emissions per unit of output as renewable energy consumption increases, that is, carbon emissions are procyclical but emissions per unit of output are countercyclical. Second, an energy efficiency improvement provokes a “rebound effect” above 100% (the backfire effect), resulting in a rise of pollutant emissions by increasing energy use. Third, a technological improvement in emissions leads to a reduction in emissions per unit of fossil fuel, but also implies a slow-down in the adoption of renewable energy sources. Finally, we consider the case of a decentralized economy in which the government chooses an optimal specific tax on fossil fuel to maximize social welfare. We show that the “second-best” policy is highly effective in correcting the negative effects of the environmental externality and able to almost achive the centralized economy outcome.

Increase energy use efficiency and economic benefit with reduced environmental footprint in rice production of central China.

Identifying an energy-efficient system with low energy use, low global warming potential (GWP), and high profitability is essential for ensuring the sustainability of the agro-environment. Given the global importance of China's rice production, this study determines energy, environmental, and economic performances of transplanted (TPR) and direct-seeded rice system (DSR) in central China. The results showed that total energy inputs for TPR and DSR were 31.5 and 22.8 GJ ha-1 across two growing seasons, respectively. Higher energy input for TPR primarily resulted from extra energy use of the nursery beds and transplanting. Higher energy output of DSR (202.5 GJ ha-1) over that of TPR (187.7 GJ ha-1) was due to a slightly higher yield from DSR. Therefore, DSR exhibited significantly higher energy use efficiency than that of TPR. Lower specific energy for DSR (2.78 MJ kg-1) relative to TPR (4.02 MJ kg-1) indicated that the energy used to produce per unit of rice grain could be reduced by 30.8% by adopting DSR. On average, GWP of DSR was reduced by 5.6% compared with TPR. Moreover, DSR had a 55.8% higher gross return and a 25.7% lower production cost than those of TPR. Overall, compared with TPR, DSR has the potential to increase gross economic return and energy output with reduced energy input and emissions. Therefore, this study suggests that DSR is an environmentally-sound and economically-viable production system. As such, DSR is noted as an energy-efficient and climate-smart production system that could be used by policymakers and farmers to achieve not only improvements in the environment but also financial benefits.