Achieve Carbon Neutrality Research Articles

1-Dimensional metal Nitride-Supported platinum nanoclusters for Low-Temperature hydrogen production from formic acid

Formic acid is widely recognized as a suitable liquid hydrogen carrier for linking renewable energies toward various economic sectors. Designing efficient and stable heterogeneous catalysts for low-temperature hydrogen generation from formic acid is vital for this topic. In this study, a rational hierarchical architecture is explored by assembling Pt nanoclusters with 1-dimensional (1D) GaN nanowires. The catalytic architecture describes a considerable hydrogen production activity of 54.89 mmol·gcat−1·h−1 with a nearly 100 % selectivity and a turnover frequency (TOFPt) of 505.7 h−1 under near ambient condition, enables the achievement of a high turnover number of 306,981 mol H2 per mole Pt over 200 h of long-term operation. Through comprehensive mechanistic studies, it is unraveled that the synergistic effect between Pt nanoclusters and GaN significantly reduces the energy barrier for the formation of the key HCOO* intermediate from formic acid dehydrogenation whereas significantly increase the energy barrier of HCOOH → HCO* + *OH. It thus simultaneously contributes to improving the activity and selectivity of formic acid decomposition toward H2. This study proposes a promising strategy for hydrogen generation from formic acid at low temperatures, which is critical for achieving carbon neutrality by coordinating industrial waste heat with renewable energies via liquid hydrogen carriers.

Projecting Future Mercury Emissions From Global Biofuel Combustion Under the Carbon Neutrality Target

AbstractBiomass plays a crucial role in the low‐carbon energy transition, with a projected contribution of 18.7% to the global energy supply by 2050. However, biofuel combustion has been a notable source of toxic mercury emissions, yet the future trends and distribution of the emissions remain inadequately understood. Here, we projected biofuel combustion under various Shared Socioeconomic Pathways (SSPs) using the Global Change Assessment Model and assessed associated mercury emissions in cooking, heating, and power generation over 2020–2050, aligning with the carbon neutrality target. Our analysis reveals that global biofuel mercury emissions are projected to be 9.90–18.40 tons by 2050, compared to the annual emissions of 13.89 tons in 2020. Notably, a substantial increase in emissions from power generation is expected, escalating from 0.57 tons in 2020 to 4.69–8.27 tons by 2050, with China and Southeast Asia emerging as primary contributors. Conversely, mercury emissions from cooking and heating are expected to decrease from 13.32 tons in 2020 to 4.40–11.53 tons by 2050, except in Africa under SSP2, where the emissions may increase from 5.91 to 6.69 tons. Our findings provide a scientific basis for policies aimed at achieving carbon neutrality targets while adhering to the Minamata Convention on Mercury.

Self-adaptive radiation recuperator with double phase transition temperature switches based on VO2 intelligent films

Developing renewable energy for heating and cooling to achieve carbon neutrality and environmental protection is of great significance. The combination of photothermal (PT) and radiative cooling (RC) technology to continuously obtain energy throughout the day is gradually attracting interest, in which vanadium dioxide (VO2) intelligent phase transition film serves as a bridge between the daytime PT mode and the nighttime RC mode. The high phase transition temperature of VO2 poses a challenge to environmental adaptability and dynamic switching in practical applications. In this work, a novel self-adaptive radiation recuperator with double phase transition temperature (37 °C and 68 °C) switches is proposed to exchange energy from the sun and outer space by radiation. Compared with VO2 and W-doped VO2 single-layer structure, this method has a higher self-adaptability to easily achieve the phase transition temperature of mode switching. The absorptivity of the radiation recuperator is 0.75 in the solar band (0.3–2.5 μm), and the emissivity switching capability is present from 0.3 to 0.86 in the atmospheric window band (8–14 μm). The transition mode generated by the presence of double phase transition temperature improves temperature self-adaptability and improves energy collection efficiency in dynamic environments.

How can managerial practices for Circular Business Models contribute to achieving carbon neutrality? A taxonomy of their preventive and corrective role

The implementation of managerial practices for Circular Business Models (CBMs) can significantly advance a sustainability transition pathway of companies, particularly in addressing environmental issues. However, there is a lack of studies investigating how these practices can contribute to achieving carbon neutrality. This research gap is addressed in this study using a mixed-methodological approach: the Decision-Making Trial and Evaluation Laboratory (DEMATEL) and the Delphi methods. From the literature, we identified a set of eight prevalent managerial practices for CBMs implemented by companies across various industry sectors. The experts involved in the empirical analysis assessed this set of practices using first the DEMATEL, and a preliminary taxonomy showing the contribution of managerial practices to achieving carbon neutrality was proposed, considering their preventive (i.e., avoiding carbon emissions) and corrective (i.e., capturing and storing carbon from the atmosphere) role. The preliminary taxonomy was subsequently refined through the Delphi method to reduce its degree of subjectivity and enhance its effectiveness. Our results show how managerial practices for CBMs can play both a preventive and corrective role in achieving carbon neutrality, with ‘Product Design for Circularity’ and ‘Energy efficiency and usage of renewable energy sources’ standing out as contributing more than the others. Companies aiming to pursue a decarbonization strategy can also leverage a range of managerial practices for CBMs.

ПРИОРИТЕТЫ ТЕХНОЛОГИЧЕСКОЙ МОДЕРНИЗАЦИИ ДЛЯ ДОСТИЖЕНИЯ УГЛЕРОДНОЙ НЕЙТРАЛЬНОСТИ ЭКОНОМИКИ КАЗАХСТАНА

This article explores the directions for improving the technological development of Kazakhstan in light of the implementation of the Strategy for Achieving Carbon Neutrality by 2060. By studying international experience and assessing the level of technological development and scientific achievements of the country within the context of global trends, the authors identify key problem areas and barriers that hinder the fulfillment of national commitments in researching technologies to reduce greenhouse gas emissions in the country's basic economic sectors. The article concludes by justifying the priority paths and mechanisms for the technological modernization of the national economy as a key driver for Kazakhstan's transition to low-carbon development. Keywords: Technological modernization, carbon neutrality, decarbonization of basic sectors, industrial-innovative development, energy efficiency, greenhouse gases.

Enhanced Data Processing and Machine Learning Techniques for Energy Consumption Forecasting

Energy consumption plays a significant role in global warming. In order to achieve carbon neutrality and enhance energy efficiency through a stable energy supply, it is necessary to pursue the development of innovative architectures designed to optimize and analyze time series data. Therefore, this study presents a new architecture that highlights the critical role of preprocessing in improving predictive performance and demonstrates its scalability across various energy domains. The architecture, which discerns patterns indicative of time series characteristics, is founded on three core components: data preparation, process optimization methods, and prediction. The core of this architecture is the identification of patterns within the time series and the determination of optimal data processing techniques, with a strong emphasis on preprocessing methods. The experimental results for heat energy demonstrate the potential for data optimization to achieve performance gains, thereby confirming the critical role of preprocessing. This study also confirms that the proposed architecture consistently enhances predictive outcomes, irrespective of the model employed, through the evaluation of five distinct prediction models. Moreover, experiments extending to electric energy validate the architecture’s scalability and efficacy in predicting various energy types using analogous input variables. Furthermore, this research employs explainable artificial intelligence to elucidate the determinants influencing energy prediction, thereby contributing to the management of low-carbon energy supply and demand.

Porous nickel-based catalyst doped with fluorine can efficiently electrocatalyze the reduction of CO2 to CO

The electrocatalytic carbon dioxide reduction reaction (CO2RR) to produce high-value-added products is considered an effective method for achieving carbon neutrality and mitigating greenhouse effects. However, due to the coexistence of competing hydrogen evolution reaction (HER) alongside CO2RR, the selectivity of catalysts still requires improvement. Moreover, the complex preparation methods and high cost of noble metal catalysts pose challenges. Therefore, it is crucial to find a catalyst that is easy to prepare, cost-effective in terms of raw materials, and exhibits high selectivity. In this study, chitosan was utilized as a carbon source for the catalyst, with nickel as the primary metal. Through gasification at 650°C and morphology control via formation of hollow structures using Cd metal particles, along with F doping modification, an electrocatalyst (NiCd650F0.2) was prepared. This catalyst exhibited the highest CO selectivity of 90.3 % at −1 V vs. RHE, with a CO partial current density of −10.68 mA·cm−2 at −1.2 V vs. RHE. Stability tests demonstrated that its selectivity and activity remained excellent over 8 hours. Density functional theory (DFT) calculations further indicated that F doping significantly lowers the adsorption energy barrier of reactions, promoting reaction kinetics and enhancing catalyst selectivity.

CO2 hydrogenation to methanol over Cu-CeO2-ZrO2 catalysts: The significant effect of metal-support interaction

CO2 hydrogenation to methanol is an important pathway to achieving carbon neutrality, with metal-support interaction (MSI) being crucial in the design and optimization of catalysts for this process. In this study, Cu-CeO2-ZrO2 catalysts (CuCe + Zr, CuZr + Ce, CeZr + Cu, and CuCeZr) with different interactions between metal Cu and supports were successfully prepared. We mainly address the problem that how the MSI affects the catalytic performance. The CuCeZr prepared by one step solid-phase method shows the optimal catalytic activity and stability for CO2 hydrogenation, even better than the benchmark commercial Cu-ZnO-Al2O3 catalyst for syngas to methanol. Based on the investigation of the structure-performance relationship of catalysts, we propose that the excellent catalytic activity of CuCeZr is mainly determined by its largest surface area of metallic Cu (SCu) and the most amount of Cu species at Cu-support interface, both resulting from the strongest MSI between metallic Cu and CeO2-ZrO2 support. Furthermore, in situ DRIFTS showed that the strong SMI in CuCeZr promotes the formation of formate and its rapid transfer to methoxy, thereby efficiently producing methanol. This work reveals the intrinsic active sites of Cu-CeO2-ZrO2 catalysts from a MSI perspective, providing useful insights for researchers to design highly efficient Cu-based catalysts.

Can green finance act as a catalyst to renewable energy deployment? Evidence from China using a spatial econometric approach

There is international consensus on leveraging green finance in renewable energy deployment because both are viewed as crucial for achieving carbon neutrality. We employ a spatial econometric approach to examine whether green finance can stimulate renewable energy uptake using energy data from 30 provinces in China for the period 2006–2020. We also investigate the moderating influence of government interventions in the form of environmental regulations and natural gas promotion. To assess the overall impact of China's inaugural green bond policy, introduced in 2015, we conduct a quasi-natural experiment combining the spatial Durbin model and difference-in-difference (DID) method. The empirical results reveal the following: Firstly, green finance can enhance renewable energy utilization, with spillover effects observed from green finance in one province to neighboring provinces. Secondly, environmental regulations and natural gas promotion have beneficial moderating effects, supporting green finance in advancing renewable energy deployment. Thirdly, a high level of implementation of green bond policy generates local and external boosts for renewable energy. These findings can inform government and environmental organizations in designing and implementing policies to expand renewable energy deployment.

New Insights on the Understanding of Sulfur-Containing Coal Flotation Desulfurization

The clean and efficient utilization of coal is a promising way to achieve carbon neutrality. Coking coal is a scarce resource and an important raw material in the steel industry. However, the presence of pyrite sulfur affects its clean utilization. Nonetheless, this pyrite could be removed using depressants during flotation. Commonly used organic depressants (sodium lignosulfonate (SL), calcium lignosulfonate (CL), and pyrogallol (PY)) and inorganic depressants (calcium oxide (CaO) and calcium hypochlorite (Ca(ClO)2)) were chosen in this study. Their inhibition mechanism was discussed using FTIR, XPS, and molecular dynamics (MD) methods. The desulfurization ability of organic depressants was shown to be better than inorganic ones. Among the organic depressants, PY proved to be advantageous in terms of low dosage. Physical adsorption was identified as the main interaction form of SL, CL, and PY onto the surface of pyrite, as evidenced from FTIR and XPS analyses. Similarly, MD simulation results showed that hydrogen bonds played a proactive role in the interactions between PY and pyrite. The diffusion coefficient of water molecules on the pyrite surface was also observed to decrease when organic depressants were present, indicating an increase in the hydrophilicity of pyrite. This research is of great significance to utilize sulfur-containing coal and minerals.

Solar Hydrogen Production and Storage in Solid Form: Prospects for Materials and Methods.

Climatic changes are reaching alarming levels globally, seriously impacting the environment. To address this environmental crisis and achieve carbon neutrality, transitioning to hydrogen energy is crucial. Hydrogen is a clean energy source that produces no carbon emissions, making it essential in the technological era for meeting energy needs while reducing environmental pollution. Abundant in nature as water and hydrocarbons, hydrogen must be converted into a usable form for practical applications. Various techniques are employed to generate hydrogen from water, with solar hydrogen production-using solar light to split water-standing out as a cost-effective and environmentally friendly approach. However, the widespread adoption of hydrogen energy is challenged by transportation and storage issues, as it requires compressed and liquefied gas storage tanks. Solid hydrogen storage offers a promising solution, providing an effective and low-cost method for storing and releasing hydrogen. Solar hydrogen generation by water splitting is more efficient than other methods, as it uses self-generated power. Similarly, solid storage of hydrogen is also attractive in many ways, including efficiency and cost-effectiveness. This can be achieved through chemical adsorption in materials such as hydrides and other forms. These methods seem to be costly initially, but once the materials and methods are established, they will become more attractive considering rising fuel prices, depletion of fossil fuel resources, and advancements in science and technology. Solid oxide fuel cells (SOFCs) are highly efficient for converting hydrogen into electrical energy, producing clean electricity with no emissions. If proper materials and methods are established for solar hydrogen generation and solid hydrogen storage under ambient conditions, solar light used for hydrogen generation and utilization via solid oxide fuel cells (SOFCs) will be an efficient, safe, and cost-effective technique. With the ongoing development in materials for solar hydrogen generation and solid storage techniques, this method is expected to soon become more feasible and cost-effective. This review comprehensively consolidates research on solar hydrogen generation and solid hydrogen storage, focusing on global standards such as 6.5 wt% gravimetric capacity at temperatures between -40 and 60 °C. It summarizes various materials used for efficient hydrogen generation through water splitting and solid storage, and discusses current challenges in hydrogen generation and storage. This includes material selection, and the structural and chemical modifications needed for optimal performance and potential applications.

Spatiotemporal evolution and driving factors of China's carbon footprint pressure: Based on vegetation carbon sequestration and LMDI decomposition

Evaluating carbon footprint pressure (CFP) scientifically and quantifying the environmental impact of economic activities precisely are crucial for informing policies on carbon emission reduction and achieving carbon neutrality in China. This study revealed China's CFP from 2005 to 2021 using data sets of fossil fuel carbon emissions and vegetation carbon sequestration from remote sensing. We investigated the drivers of CFP using LMDI decomposition. Additionally, we used the Tapio model to examine the decoupling of CFP and economic growth. The findings indicate that China's CFP has increased over time and shows a positive spatial correlation. Rapid economic growth and significant population expansion are the primary drivers of the surge in CFP. Conversely, optimizing energy structure, reducing energy intensity, and enhancing ecological quality are key to alleviating the rising pressure on China's carbon footprint. Moreover, we observe a weak decoupling of China's CFP and economic growth. Notably, it is more challenging to achieve an ideal decoupling state in the western region than in the central and eastern regions.

Carbon emission accounting and decarbonization strategies in museum industry

Carbon peaking and achieving carbon neutrality have emerged as pivotal strategic imperatives in China. These objectives not only drive a shift in production, lifestyle, and consumption patterns but also illuminate a path towards a comprehensive green metamorphosis in China’s economic and social development landscape. The distinctive nature of museums as quintessential public edifices, requiring sustained regulation of temperature and humidity alongside attracting substantial foot traffic, positions them as crucial pioneers in the pursuit of carbon peaking and neutrality. It is essential for museums to leverage their leadership and advocacy roles to catalyze low-carbon construction practices across society. This study delves into the energy dynamics specific to the museum sector, delving into the recycling of exhibition materials, methodologies for carbon footprint assessments of visitors and museum staff, and the establishment of a standardized carbon emission accounting framework tailored to the museum industry. Through meticulous examination of representative cases and subsequent analysis, this research delineates decarbonization strategies, offering indispensable technical scaffolding for carbon assessment and emission reduction efforts within the museum realm.

Higher Onshore Wind Energy Potentials Revealed by Kilometer‐Scale Atmospheric Modeling

AbstractReliable and highly resolved information about onshore wind energy potential (WEP) is essential for expanding renewable energy to eventually achieve carbon neutrality. In this pilot study, simulated 60 m wind speeds (ws60m) from a km‐scale, convection‐permitting 3.3 km‐resolution ICON‐LAM simulation and often‐used 31 km‐resolution ERA5 reanalysis are evaluated at 18 weather masts. The estimated ICON‐LAM and ERA5 WEPs are then compared using an innovative approach with 1.8 million eligible wind turbine placements over southern Africa. Results show ERA5 underestimates ws60m with a Mean Error (ME) of −1.8 m s−1 (−27%). In contrast, ICON‐LAM shows a ME of −0.1 m s−1 (−1.8%), resulting in a much higher average WEP by 48% compared to ERA5. A combined Global Wind Atlas‐ERA5 product reduces the ws60m underestimation of ERA5 to −0.3 m s−1 (−4.7%), but shows a similar average WEP compared to ERA5 resulting from the WEP spatial heterogeneity.

A dynamic multi-objective optimization model for inner-industry carbon responsibility allocation based on carbon tax and carbon offsets accounting

The setting of Intergovernmental Panel on Climate Change (IPCC) raises concerns on curbing the excessive carbon emissions, and European Union (EU) has been proactively attempting “green” initiatives striving to achieve carbon neutrality. The current Carbon Border Adjustment Mechanism (CBAM) only works on short-term carbon reduction without much “greenness” investment incentives so far, and few studies focus on the long-standing inner-industrial carbon reduction coordination. To address these issues, this paper creatively presents a dynamic multi-objective carbon responsibility allocation model (CRAM) for EU carbon market, allows the carbon trade with a taxation based on carbon offsets accounting, and considers the final targets of sustainable “greenness” investment incentives. To find the optimal results of the designed dynamic CRAM, an improved KT-NSGA-II algorithm is proposed to detect the Pareto frontiers of each successive periods. Data from EU Cement and Aluminium industries are then selected for empirical analysis to compare the proposed CRAM to conventional CBAM model. The findings demonstrate that the superiority of CRAM in carbon emissions reduction, economic benefits improvement and green invests encouragement. With the adjustment of the inner-industrial carbon allowance trade, total carbon emissions decreased by 28.03% and the “greenness” investment initiative increased by 39.24% in contrast to the CBAM. The sensitivity analysis of the model also provides suggestions on the settings of carbon quota and tax with different industrial production process, and proposes policy recommendations for CRAM implementation.

China's carbon neutrality policy facilitates halving industrial water withdrawal

Abstract China concurrently confronts acute water resource challenges and substantial carbon emissions, with its industrial sector being a significant freshwater consumer and a primary carbon emitter. China has committed to achieving carbon neutrality by 2060, yet the exact impact of this goal on industrial water withdrawal (IWW) remains unclear. Here, we project IWW in China considering both scenarios with and without the carbon neutrality target, based on industry-specific water quota standards and projections of industrial product output. Our findings indicate a 53.76% (51.41 km³) reduction of IWW by 2060 under a carbon neutrality scenario, compared to business-as-usual, with the IWW peak advancing from 2035 to 2025. The thermal power industry holds the largest water withdrawal reduction, accounting for 75.74% (38.94 km³) of the total reduction. Additionally, both the East coastal region and the Middle Yangtze River region could reduce 62.08% (31.96 km³) of IWW under the CN scenario, with Jiangsu province emerging as a significant contributor. This study provides a reliable basis for evaluating the potential for future water withdrawal reduction within the industrial sector and suggests that achieving the carbon neutrality target could offer a promising direction for alleviating China's water scarcity challenges.

A research on the construction path of ecological city under the concept of carbon neutrality—A case study of Chinese city

<p class="GTC-Norm" style="text-align: justify; text-justify: inter-ideograph; text-indent: 0cm; line-height: 120%; margin: 12.0pt 0cm 6.0pt 0cm;"><span lang="EN-US" style="font-size: 10.0pt; line-height: 120%; font-family: 'Times New Roman',serif; color: windowtext;">Under China’s ambitious goal of peaking carbon dioxide emissions by 2030 and achieving carbon neutrality by 2060, we should re-examine the way of urban development, study the key to carbon pollution, change the original urban renewal path, and seek energy-saving and emission reduction. Therefore, this paper takes Xiamen City as an example, through questionnaire survey, mathematical statistics analysis and other methods, combined with the practice of low-carbon city and ecological civilization construction in Xiamen City, this paper makes an in-depth analysis of carbon pollution problems such as transportation carbon emissions, domestic waste disposal carbon emissions and industrial waste carbon emissions in Xiamen City, and puts forward the urban renewal path of Xiamen City to effectively reduce carbon emissions based on the concept of carbon neutrality, which provides a low-carbon plan for Xiamen City</span><span lang="EN-US" style="font-size: 10.0pt; line-height: 120%; font-family: 'Times New Roman',serif; mso-fareast-font-family: 等线; mso-fareast-theme-font: minor-fareast; color: windowtext; mso-fareast-language: ZH-CN;">’</span><span lang="EN-US" style="font-size: 10.0pt; line-height: 120%; font-family: 'Times New Roman',serif; color: windowtext;">s urban renewal and is of great significance for Xiamen City to achieve the dual-carbon goal.</span></p>

The phenomenon of China’s carbon accounting policies and practices

Purpose This study aims to explore China’s carbon accounting policies and practices to enhance its carbon accounting and trading practices and achieve carbon neutrality. Design/methodology/approach This study adopts a phenomenological methodology to explore carbon accounting by setting the scope of the phenomenon, establishing research methods, conducting interviews with 30 participants from 14 emitting entities and four accounting firms and establishing methods for data analysis. Five themes were identified using a five-step coding method. Findings The results show no uniformity in the accounting treatment of carbon trading; however, common characteristics exist, and they have generally adopted simplified and conservative accounting methods under China’s emission trading scheme. Their common characteristics are that the granted allowances are not recognised as assets by most emitting entities, emissions allowance assets are measured using the historical cost method, most emitting entities only conduct accounting when there are actual cash flows or outflows with regard to carbon emissions allowance trading, and only a few emitting entities disclose carbon trading information in their financial statements or corporate social responsibility reports. Originality/value This study highlights accountants’ crucial role in carbon activities by guiding emitting entities’ low-carbon initiatives and culture and transforming managers’ mindsets. It also introduces the China Accounting Standards Committee-based accounting methods for allowances and obligations, aiding carbon disclosure quality and sustainability. These findings also inform the carbon accounting standards that may enhance corporate accountability and address climate change.

Ultrafine Rhodium-Chromium Mixed-Oxide Cocatalyst with Facet-Selective Loading for Excellent Photocatalytic Water Splitting.

The development of water-splitting photocatalysts capable of generating green hydrogen (H2) from water and sunlight is crucial for achieving carbon neutrality. Further enhancement of the photocatalytic water-splitting activity is essential to realizing this objective. Photocatalysts with specific exposed crystal facets can facilitate efficient charge separation of electrons/holes, thereby achieving high activity for water splitting. However, there have been no reports of ultrafine (∼1 nm) cocatalysts being loaded onto specific crystal facets of photocatalysts, despite cocatalysts being the actual reaction sites for water splitting. This study establishes a novel method for achieving facet-selective loading of ultrafine H2-evolution cocatalysts onto the {100} facets, which are the H2-evolution facets, of a strontium titanate photocatalyst. The resulting photocatalyst exhibits the highest apparent quantum yield achieved to date for strontium titanate. This research holds the potential to further improve various types of advanced photocatalysts and is expected to accelerate the transition to carbon neutrality.

Optimum power control and coordinate sizing for the stand-alone wind-energy storage integrated hydrogen production system

The stand-alone wind-energy storage integrated hydrogen production technique is becoming a key and emerging technique to achieve carbon neutrality. However, the conflict between the random wind power fluctuation and the stable power demand of the electrolyzer lowers the system's operation stability and reliability. To address this issue, a modified output power smooth control strategy for the wind turbine that considers the dynamic performance of the electrolyzer is proposed. The output power of the wind turbine can be smoothed following the need of the electrolyzer, which helps reduce the electrolyzer's start-stop times and the battery's charging and discharging cycles. Eventually, the efficiency and life span of the hydrogen production system is enhanced. Afterward, an operational strategy for the hydrogen production system is provided, and a coordinated sizing strategy for the wind turbine, energy storage system, and electrolyzer is proposed. The results of case studies, which use the real data obtained from a hydrogen production demonstration project, prove that the overall lifecycle revenue for the hydrogen production system is remarkably increased. Finally, a long-term simulation model for a stand-alone wind-energy storage integrated hydrogen production system was developed. Simulation results validate the effectiveness of the proposed method.