• Energy Research
• Closed Access close
• Open Source close
• 12. Responsible consumption close
• 6. Clean water close
• EC close

Abstract The economic giant China, enjoying miraculously high economic performance since the 1980s, is currently facing an economic performance slowdown, along with environmental sustainability challenges. Energy-industry investments might serve as a potential driver of economic performance, indirectly inducing environmental sustainability through investments in the energy-industry transition from old technology to a renewable one. This research provides an empirical assessment of the causal bond between energy-industry investment and economic performance across the regional development levels, employing a dynamic longitudinal data modeling on China’s 27 provincial and municipality units from 1997 through 2017. It developed an economic performance model to incorporate energy-industry investment as an aggregate production growth input. The core empirical findings are as follows. Firstly, the energy-industry investment and economic performance induced a positive and statistically significant mutual influence, manifested from their parameter estimates. Secondly, a bilateral causal bond is unveiled between energy-industry investment and economic performance based on the Dumitrescu-Hurlin technique, confirming the feedback hypothesis of a causal bond between the two variables. The results are consistent across the under-analysis panels in terms of the nature of the influence; however, the induced degrees of their influence significantly differed across the regional development levels. The intensity of the direct influence of energy-industry investment (0.049) on economic performance lags behind the feedback influence of economic performance (1.069) on energy-industry investment. Additionally, considerable heterogeneities are detected in influence intensities across the regional panels. Eastern China (region of high development) displayed the most substantial direct (0.058) and feedback influence (1.193), while western China manifested the least substantial intensity of direct (0.030) and feedback influence (0.836). After that, the central China (region of medium development) demonstrated a medium intensity of direct (0.037) and feedback influence (0.996). Finally, among other regressors, human capital, physical capital, inflation rate, and trade presented a positive and significant influence on economic performance. In contrast, the foreign direct investment significantly influenced the economic performance only in the eastern China. The empirical findings implied that energy-industry investment might serve as a vital driver of economic performance, with the most significant role in the highly developed regions and the least significant in the low developed regions, given the important explanatory variables. Based on empirical findings, policies are suggested.

Effects of climate change on water resources availability have been studied extensively; however, few studies have explored the sensitivity of water to several factors of change. This study aimed to explore the sensitive of water balance in water resources systems due to future changes of climate, land use and water use. Dynamical and statistical downscaling were applied to four global climate models for the projections of precipitation and temperature of two climate scenarios RCP 4.5 and RCP 8.5. Land use projections were carried out through a combination of Markov chains and cellular automata methods. These projections were introduced in a hydrologic model for future water supply evaluation, and its interactions with water use projections derived from a statistical analysis which served to assessment deficits and surplus in water to 2050. This approach was applied in the Machangara river basin located in the Ecuadorian southern Andes. Results showed that the water supply exceeds the water demand in most scenarios; however, taking into account the seasonality, there were months like August and January that would have significant water deficit in joint scenarios in the future. These results could be useful for planners formulating actions to achieve water security for future generations.

The accelerated urbanization process generates a significant increase in energy, whose sources are mainly polluting. The harmful effects of both processes are reflected in climate change. This article examines the equilibrium and causality relationship among urban concentration, non-renewable energy consumption, and the real per capita output in 110 countries during 1971-2017. Using data from the World Bank's World Development Indicators (2018), we classify countries into four groups according to their level of development. Our evidence suggests that urban concentration has a negative effect on real per capita output in high-income countries, while non-renewable energy consumption has a positive effect on all groups of countries. The cointegration tests show that there is short- and long-term equilibrium in all groups of countries. The results of the DOLS and PDOLS models indicate that the strength of the cointegration vector is weak in most of the countries and groups analyzed. The Granger-type causality tests show that there is bidirectional causality from the real per capita output to the urban concentration in high and middle-low-income countries. There is unidirectional causality from the population concentration towards the real per capita output in the low-income countries; from the non-renewable energy consumption to the real per capita output in high-income countries; from the real per capita output to the non-renewable energy consumption in the countries of medium-high and medium-low income; and from urban concentration to non-renewable energy consumption in high- and medium-high-income countries. Our results highlight the importance of promoting policies of urban planning and generation and consumption of renewable energy without limiting the expansion of the output.

CO2 emissions are the leading causes of deterioration in air quality and global warming. Likewise, it has been shown that clean energy reduces air pollution, so this would be a way out of environmental pollution. Some previous studies have focused on knowing the determinants of environmental pollution; however, they have omitted the State's role. Thus, this study explores the long-term nexus between CO2 emissions and renewable energy, energy efficiency, fossil fuels, GDP, property rights from 1995 to 2019 in nine developed countries. The results reveal a long-term equilibrium relationship in developed European countries, but not in developed non-European countries. The main results show that renewable energy and energy efficiency are negatively correlated with CO2 emissions. In developed European countries, a 1% increase in renewable energy consumption represents a 0.03% decrease in CO2 emissions. Finally, some policy measures are suggested to achieve environmental sustainability.

Most of the environmental degradation literature evaluates the determinants of polluting gas emissions as a spatially static process. However, environmental pollution is a problem that is not limited to the borders of the countries. One way to capture temporal and spatial changes in pollutant emissions is by using the benefits of spatial panel data models. This research aims to empirically examine the environmental impact of the shadow economy, the globalisation index, and the human capital index in 101 countries during 1995-2018. We employ a set of spatial autoregressive models (SAR), Durbin spatial models (SDM), and spatial lag models (SLX) of panel data to estimate direct, indirect, and total impacts. The results are stable before changes in the econometric specification and different ways of calculating spatial weights matrix. The results show that polluting gas emissions have a high spatial dependence on all specifications. The interdependence between the countries explains the spillover effect of environmental pollution on the rest of the countries that are geographically close. The policy implications derived from our research point to achieving sustainable economic and environmental development, where coordinated actions among countries and greater regulation of the behaviors of economic agents related to the shadow economy are recommended.

AbstractPrevious literature does not incorporate the spillover effects of institutional factors in the analysis of the determinants of energy intensity. This research aims to empirically examine the impact of institutional and economic factors on energy intensity using spatial panel data models. Specifically, the institutional factors included are civil liberties, political corruption, and women's political empowerment. We find robust evidence that there are spillover effects from regressors on the energy intensity of countries. We find that the index of civil liberties, political corruption, and women's political empowerment reduce energy intensity. In addition, we find robust evidence that real output per capita and oil price reduce energy intensity, while manufacturing industry increase it. Our results indicate that manufacturing activity requires greater attention from policymakers and academics to mitigate the harmful aspects of energy intensity. Likewise, our results constitute a new look at the approach to mechanisms to reduce energy intensity to achieve sustainable economic development consistent with Sustainable Development Goals 7 and 12.

AbstractThis study aims to evaluate the effects of the co‐digestion of agricultural residues with manure from camelids from the Andean zone. Different combinations of llama manure (LM) and vicuñas (VM) were made with amaranth (AS), quinoa (QS), and wheat (WS) residues. They were fermented using sewage sludge as inoculum. The co‐digestion was evaluated under mesophilic conditions for 40 days. The ratios of volatile substances of substrate / co‐substrate evaluated were 0:100; 25:75; 50:50, 75:25, and 100:0. Two substrate / inoculum ratios (SIR 1:1 and SIR1:2) were also evaluated. The results indicate that the maximum methane accumulation rate is obtained in SIR 1:1 for a VM‐AS ratio (25:75) with 540 mL/g volatile solid (VS). In general, the results did not increase with the increase in inoculum; rather, the tendency to improve methane yield is associated with an increase in the amount of agricultural residues, mainly AS. Regarding the kinetic modeling, the transfer model is the one that best adjusted the predicted values to those observed with an r2 between 0.991 and 0.999, and an RMSE value between 2.06 and 13.62 mL/g (volatile solid) VS. Finally, all the trials presented synergistic effects in their co‐digestion except the digesters formed by LM‐AS, LM‐QS and LM‐WS of SIR 1:2. These presented antagonistic effects in which the addition of the co‐substrate generated competition with the substrates, reducing methane production. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd

Due to regular influx of organic matter and nutrients, waste stabilization ponds (WSPs) can release considerable quantities of greenhouse gases (GHGs). To investigate the spatiotemporal variations of GHG emissions from WSPs with a focus on the effects of sludge accumulation and distribution, we conducted a bathymetry survey and two sampling campaigns in Ucubamba WSP (Cuenca, Ecuador). The results indicated that spatial variation of GHG emissions was strongly dependent on sludge distribution. Thick sludge layers in aerated ponds and facultative ponds caused substantial CO2 and CH4 emissions which accounted for 21.3% and 78.7% of the total emissions from the plant. Conversely, the prevalence of anoxic conditions stimulated the N2O consumption via complete denitrification leading to a net uptake from the atmosphere, i.e. up to 1.4±0.2 mg-N m-2 d-1. Double emission rates of CO2 were found in the facultative and maturation ponds during the day compared to night-time emissions, indicating the important role of algal respiration, while no diel variation of the CH4 and N2O emissions was found. Despite the uptake of N2O, the total GHG emissions of the WSP was higher than constructed wetlands and conventional centralized wastewater treatment facilities. Hence, it is recommended that sludge management with proper desludging regulation should be included as an important mitigation measure to reduce the carbon footprint of pond treatment facilities.

An air exposed single-chamber microbial fuel cell (SCMFC) using microalgal biocathodes was designed. The reactors were tested for the simultaneous biodegradation of real dye textile wastewater (RTW) and the generation of bioelectricity. The results of digital image processing revealed a maximum coverage area on the biocathodes by microalgal cells of 42%. The atmospheric and diffused CO2 could enable good algal growth and its immobilized operation on the cathode electrode. The biocathode-SCMFCs outperformed an open circuit voltage (OCV), which was 18%-43% higher than the control. Furthermore, the maximum volumetric power density achieved was 123.2 ± 27.5 mW m-3. The system was suitable for the treatment of RTW and the removal/decrease of COD, colour and heavy metals. High removal efficiencies were observed in the SCMFCs for Zn (98%) and COD (92-98%), but the removal efficiencies were considerably lower for Cr (54-80%). We observed that this single chamber MFC simplifies a double chamber system. The bioelectrochemical performance was relatively low, but the treatment capacity of the system seems encouraging in contrast to previous studies. A proof-of-concept experiment demonstrated that the microalgal biocathode could operate in air exposed conditions, seems to be a promising alternative to a Pt cathode and is an efficient and cost-effective approach to improve the performance of single chamber MFCs.