Which plastic recycling approaches maximize climate benefits and balance fossil energy? Evidence from the Japanese experience

Impact of renewable and fossil energy on sectoral CO2 emissions: empirical evidence from the United States and China

The problem of fossil energy limitations encourages the development of renewable energy, one of which is biomass. Wood powder waste that has been underutilized has the potential to be processed into biomass pellets as an environmentally friendly alternative fuel. This study aims to design dies and rollers on biomass pellet machines that are capable of processing wood powder waste into cylindrical pellets with a focus on their strength and safety analysis. The methods used to determine strength and safety are simulations using solidworks as well as theoretical calculations to validate the results. The results showed that the design of dies with a hole diameter of 8 mm and a suitable roller can produce biomass pellets with a good level of density and efficiency. Simulations of voltage, strain and safety factors on components indicate a safe and feasible design to implement. This research contributes to the development of biomass pellet machine technology and the use of wood powder waste into renewable and environmentally friendly energy.

ABSTRACT To consume fossil energy and to mitigate global warming, carbon dioxide (CO 2 ) released from burning fossil energy needs to be captured and stored, because it is believed that released carbon will lead to global temperature rise. Most of the CO 2 captured is stored in geological formations like saline aquifers and oil or gas reservoirs. This article addresses the challenges in these areas. When an aquifer has a closed boundary, the storage capacity which is the compressibility‐limited incremental storage is about 1% of the pore volume or at most a few percent because of pressure buildup. Because of this limit, many authors argue that actual aquifer boundaries are semi‐closed or open so that the aquifer size is very large or infinite. Such a large aquifer faces the challenges of reservoir characterization, and monitoring, reporting, and verification (MRV), because the large aquifer needs to be characterized, tested, and monitored, and the semi‐closed boundaries also need to be tested for CO 2 leakage. To relieve the pressure buildup, production wells are used to simulate the process of CO 2 displacing water. Then another challenge emerges from the displacement process: separation of CO 2 and water, treatment of a large volume of produced water, and reinjection of CO 2 . Water disposal can be even more problematic than CO 2 emission. Although oil and gas reservoirs are well characterized, their storage capacity is limited. The wells used in oil and gas reservoirs are Class II which does not satisfy the specifications of Class VI used for permanent CO 2 storage. CO 2 may leak through cement and interfaces of cement with reservoirs and casings, and so forth. The leakage was widely observed in existing abandoned wells and the leak rates varied significantly depending on the well conditions. Although CO 2 helps to produce oil and can be stored in a CO 2 ‐enhanced oil recovery (EOR) process, CO 2 emitted from capturing CO 2 and burning the extra oil is not lower than the amount stored. Because of these challenges and economic hurdles, the executed CO 2 storage projects are far fewer than what was planned and needed to achieve the net‐zero target, being about 6%–30%. This article suggests that more fundamental research is needed to study the techno‐economic feasibility to safely store CO 2 in geological formations and to estimate the economic burden from CO 2 storage.

Cyclopentadiene is an important intermediate that is widely used in the production of useful chemicals, high-density aviation fuels and polymers. Conventional technologies for the production of cyclopentadiene from fossil energies suffer from low yield and selectivity. Therefore, the selective production of cyclopentadiene from renewable biomass is highly expected. In this work, a series of metal phosphates were found to be effective solid acid catalysts for the selective synthesis of cyclopentadiene from the dehydration of 1,3-cyclopentanediol, a platform compound that can be obtained from the aqueous phase rearrangement of furfuryl alcohol followed by hydrogenation. Among the investigated catalysts, lanthanum phosphate (LaP) exhibited the best performance. Over it, 100% 1,3-cyclopentanediol conversion and higher than 90% carbon yield of cyclopentadiene were achieved at 473 K under atmospheric pressure. Based on the results of characterization, the excellent performance of LaP catalyst can be rationalized by its higher amount of acid sites and average pore size.

ReFi tokens as climate-finance assets: Connectedness with renewable energy token and fossil energy

From energy consumption control to carbon emission control in fossil and renewable energy rich regions: A general equilibrium analysis of Inner Mongolia

Economic development and carbon emissions across world regions: Exploring heterogeneous drivers.

Abstract Solar power is a feasible replacement for fossil fuel-based energy sources since it reduces carbon footprints and greenhouse gas emissions, qualities needed for the fight against climate change. Still, solar energy constantly faces societal, environmental, and technical obstacles. Advanced computing techniques such as artificial intelligence (AI) can help to alleviate some of these technical challenges. This paper uses the PRISMA approach on the Scopus database for bibliometric analysis to investigate AI applications in Solar Photovoltaics (PV). We then arrange publication themes, analyse the publishing pattern to identify the most significant journals and publications using author keyword data. Co-occurrence analysis and trend visualisation were assessed using VOSviewer and Biblioshiny. Based on the findings, India, China, the United States, and Saudi Arabia dominate the publishing output, with high citation counts and extensive collaboration networks. Interestingly, four institutions in Saudi Arabia emerged as the lead with the most publication counts in this field. To identify current research gaps and future directions, we also evaluated hotspots and recent advancements in the AI applications within Solar PV research. AI-driven forecasting, fault detection, performance monitoring, cybersecurity, and Internet of Things (IoT) integration, which enables real-time and autonomous decision making, could potentially take the front stage in future renewable energy research.

Wind power generation forecasting system based on multi-model intelligent fusion strategy and probabilistic forecasting technology.

Highly efficient amino-functionalized ionic liquid membrane contactor coupled system for low-concentration carbon dioxide absorption and desorption.

Abstract In recent years, Southeast Asia has experienced rapid growth in energy use and greenhouse gas emissions. At the same time, the countries in the region have increasingly become net importers of fossil energy carriers. Against this backdrop, we use a novel decomposition approach to illustrate the historical linkages between energy trade and emissions in ten countries in Southeast Asia. Projecting future developments with and without additional efforts to reduce emissions, we show that an energy transition in line with climate targets laid down in the nationally determined contributions of these countries would greatly reduce their dependence on energy imports. We estimate that decarbonization could potentially reduce aggregate spending on fossil fuel imports by a total of more than USD 140 bn by 2030. Such savings could cover more than 70% of the investments in renewable energy sources required to meet these countries’ climate targets under the Paris Agreement.

The low-carbon transition represents the defining feature of China’s economic growth over the coming decades. Based on the perspective of energy input, this paper employs a Computable General Equilibrium (CGE) model to depict China’s current macroeconomic structure. By increasing energy inputs from sectors such as coal, oil, natural gas, hydropower, thermal power, nuclear power, wind power, and photovoltaic power, it estimates the potential range of economic growth associated with the low-carbon transition of China’s industrial sectors. The study finds that: (1) during the industrial low-carbon transition, increasing electricity-based energy inputs and increasing fossil energy inputs exert different impacts on the outputs of other sectors; (2) even when increasing the same type of energy input, the growth of output in other sectors shows varying patterns; (3) substituting original energy inputs with different types of energy leads to distinct changes in sectoral outputs. Estimating the potential range of economic growth in China’s industrial low-carbon transition contributes to achieving the “dual-carbon” and economic growth goals effectively.

Achieving decoupling between economic growth and carbon emissions is imperative for global sustainable development. This study provides a comparative analysis of this decoupling process in the European Union (EU) and BRICS countries from 1996 to 2023, employing the Tapio decoupling model and Logarithmic Mean Divisia Index (LMDI) decomposition analysis. Our findings reveal a stark contrast: the EU has achieved an average annual carbon emission growth rate of −1%, predominantly characterized by strong decoupling, whereas the BRICS nations exhibit an average growth rate of 6.26%, mainly in a state of weak decoupling. The LMDI results indicate that the intensity effect is the primary driver of carbon reduction in the EU, while the income effect is the most significant factor promoting emissions growth in the BRICS bloc. A novel finding is the identification of a near-symmetrical relationship between the energy transition effect and the fossil energy structure effect in the cumulative decomposition charts, offering a new perspective for evaluating energy system changes. The study concludes that while the EU demonstrates a more advanced decoupling pathway, significant internal disparities persist. For BRICS countries, mitigating the pressure from economic and population growth through industrial upgrading, differentiated energy policies, and enhanced renewable infrastructure is crucial. These insights provide valuable policy implications for both developed and developing economies in navigating their low-carbon transitions.

Fossil-based electricity consumption in Indonesia has continued to rise in recent years, driven by accelerated economic growth, expansion of the industrial and commercial sectors, and increasing household income levels. This strong reliance on fossil energy has contributed to higher carbon emissions and heightened vulnerability to supply instability. Therefore, understanding the key determinants of electricity consumption is essential for supporting Indonesia’s national energy transition agenda toward a more sustainable energy system. This study aims to examine the influence of the industrial sector, commercial sector, and income level on fossil-based electricity consumption in Indonesia during the 2019–2023 period. The study employs panel data analysis using the Random Effect Model (REM). This model was selected through the Chow test, Hausman test, and Lagrange Multiplier test, all of which indicated that REM provides the most efficient estimation for accommodating variations across provinces and years. The data were obtained from Statistics Indonesia (BPS), PT PLN, and other relevant official publications. The results reveal that the industrial sector, commercial sector, and income level all exert a positive and significant effect on electricity consumption. Industrial and commercial activities represent the primary drivers of rising national electricity demand, while increases in per capita income contribute to greater household electricity use. The coefficient of determination (R² = 0.7201) demonstrates that the model has strong explanatory power in describing interprovincial variations in fossil-based electricity consumption. These findings highlight Indonesia’s continued dependence on fossil energy, underscoring the need to accelerate renewable energy adoption and improve energy efficiencyas strategic steps to support the national energy transition.

China’s massive reliance on fossil energy consumption is considered as the major hindrance in achieving carbon neutrality and environmental protection goals. However, China is committed to reduce the proportion of non-renewable energy for achieving the dual goals of carbon peaking and carbon neutrality by 2030 and 2060, respectively. To meet these aspiring goals, China mainly relies on technological innovations and climate protections policies implementations for transforming fossil energy to renewable energy consumption. The present research is intended to assess the impact of environmental policy stringency (EPS) and technological innovations in China’s green energy transitions. Based on the nature of research data, the quantile regression model was applied to precisely explore the drivers of green energy transitions in China from 1990 to 2020 in various quantiles. The finding indices that technology innovation, EPS, and renewable energy index had accelerated the green energy transitions, while, the non-renewable energy consumption exhibited a negative impact. The results also revealed that impact of the solar and hydro installation capacity was significantly increase in the second quantile. The empirical analysis of this study informs several policy directions aimed at facilitating China’s green energy transitions and decarbonizing goals.

This paper empirically examines the nexus between fossil energy prices and carbon emissions using a balanced panel of 119 economies spanning the period from 1990 to 2023. The baseline regression results indicate that a 1% rise in fossil energy prices results in a 0.009% reduction in CO2 emissions, equivalent to approximately 3.1 million tons of CO2. Further analysis reveals two key mechanisms. First, energy efficiency partially mediates the price–emission relationship: higher prices significantly improve efficiency, which in turn reduces CO2 emissions, although a rebound effect of 13.6% offsets part of the expected savings. Second, renewable energy penetration serves as an additional pathway, with higher prices accelerating renewable adoption and thereby contributing to carbon mitigation. Overall, the findings confirm the direct and indirect impacts of fossil energy prices on emissions, underscoring their role as an effective lever for achieving global sustainability targets. Policy implications include the need to align fossil energy prices with true economic and environmental costs, while complementing price mechanisms with efficiency standards and renewable incentives to counterbalance hirebound effects.

Abstract The German government attributes a crucial role to green hydrogen in the energy transition, as it has the potential to reduce greenhouse gas emissions when used as an energy carrier. However, currently, green hydrogen is not yet competitive. On the one hand, its production is costly, and on the other, current electrolysis capacities are insufficient to meet the potential demand. Therefore, at least during a transitional period, green hydrogen must compete with gray hydrogen produced from fossil energy sources. In this paper, we examine three government instruments aimed at increasing the market share of green hydrogen: taxes on gray hydrogen, subsidies for the green retailer, and financial support for expanding green hydrogen production capacities. In a bi-criteria, game-theoretic model, in which the government acts as the Stackelberg leader, we observe that all three measures can improve the position of green hydrogen on the market. Notably, the state’s sole intervention can significantly increase the sales volume of green hydrogen. However, if the state’s main focus is on balancing its net gain from hydrogen market interventions, it should concentrate on taxes. If finances and the sales volume of green hydrogen are equally important, the state will increasingly focus on positive measures and support capacity expansions. In contrast, if the state’s expenditures do not matter, the additional use of subsidies leads to maximizing the market share of green hydrogen.

Abstract Biogas, generated through the anaerobic digestion of organic matter, is an attractive renewable energy source due to its continuous production and utilisation cycle. Rising concerns about the environmental impact of fossil fuel-derived energy have sparked interest in developing sustainable energy alternatives. Consequently, considerable research efforts have been directed towards biogas valorisation, particularly its main component, methane (CH 4 ). This is achieved by converting raw or upgraded biogas into high-value products, such as Zeolite-templated carbons (ZTCs), and concurrently producing cleaner hydrogen gas. ZTCs are highly ordered porous structures that exhibit high surface areas, uniform pore size distributions, and large pore volumes, rendering them attractive for various applications. These applications include gas storage, CO 2 capture, supercapacitors and batteries. In this study, we focused on the utilisation of simulated biogas (CH 4 and CO 2 mixture) and pure CH 4 (in this case, simulated ‘biomethane’) for the synthesis of zeolite-templated carbons (ZTCS). When CH 4 was utilised on both the one-step and two-step processes, the obtained ZTCs had higher surface area and hydrogen (H 2 ) adsorption. The highest surface area obtained was 2974 m 2 /g, while the best H 2 storage capacity, at 1 bar, was 2.77 wt%. Structural (XRD) and morphological (SEM and TEM) characterisations were found to be indistinguishable from those of the samples obtained when fossil-derived ethylene was used as a carbon source. Unfortunately, ZTCs were not obtained when simulated biogas was used as a carbon source, due to the zeolite having a greater affinity towards CO 2 than CH 4 , primarily because of the large quadrupole moment of CO 2 . This study has demonstrated that a sustainable source of carbonaceous feedstock, such as biogas-derived ‘biomethane’, can be converted into value-added products (ZTCs), thereby creating additional economic opportunities for industries within the biogas sector.

Biomass gasification for fuel production is a lower-carbon alternative as compared to the use of fossil resources. In biomass gasification, organic material is converted to gases including hydrogen, carbon monoxide, and carbon dioxide. This process has lower net carbon emissions than combusting fossil fuels because the plants used for fuel uptake carbon dioxide while they are growing. However, biomass gasification faces several technical challenges to widespread implementation, including the need for a pure oxygen stream for optimal gasification.1 Cryogenic distillation is a common method of producing pure oxygen from air at a higher efficiency than other technologies, but its energy requirements are significant and it is most efficient at very large production volumes.2 As a result, there is motivation for an energy-efficient method of producing oxygen in systems better suited for lower production volumes.In this presentation, we describe an electro-swing approach for oxygen sorption based on Co(II)-salen complexes. Their known affinity towards oxygen, which reduces upon oxidation to the respective Co(III) adduct, allows selective binding of oxygen from air and potential release into a pure oxygen stream. There has previously been limited investigation into electrochemically-triggered release of oxygen through the application of a positive potential.3 We first characterize several Co(salen) complexes and associated electrolyte solutions via cyclic voltammetry and chronoamperometry. We then investigate the conditions required to trigger release of oxygen from the oxidized complex. Finally, we demonstrate use of Co(salen) complexes in a 2-stage electrochemical cell, in which oxygen binding and release occur at the electrodes where oxidation and reduction of the Co(salen) complex take place. Overall, this work provides a proof-of-concept for a new oxygen separation strategy that can be further assessed and optimized in the future. Acknowledgements: This research was funded by the U.S. Department of Energy’s Office of Fossil Energy under award number FE0032348.