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This article discusses the urgent need for decarbonization of energy sectors to address the energy crisis and climate change caused by conventional energy infrastructures heavily reliant on fossil fuels. The article proposes various technical efforts such as renewable energy generation, hydrogen-based clean energy storage and transmission, and demand response programs to achieve carbon neutrality. It also highlights the importance of studying and designing the new structure of renewable energy-based multi-energy systems. The article includes research topics related to modeling, analysis, and simulation of multi-energy systems, carbon footprint tracking, low-carbon planning, clean energy and carbon markets, and the application of AI and Big Data techniques. The article also presents specific research studies conducted in China on market regulation and risk measurement, control strategies for renewable energy sending systems, integration of electricity, carbon, and green certificate markets, robust unit commitment models, and planning of multi-energy systems. The authors emphasize that the views expressed in the article are solely their own and do not represent those of their affiliated organizations or the publisher. [Extracted from the article]

• A process of EG targeted CCLG process is proposed to improve the energy efficiency. • The CO 2 emissions of the whole process is only 0.018 kg-CO 2 /kg-EG. • A series of molecular simulations are used to investigate the optimal temperature and optimal C/O mass ratio for the CCLG process. • The results of MD simulations are verified with experiment results to study the reaction mechanism. The CO 2 capture technologies such as chemical-looping gasification (CLG) and reformation (CLR) receive more and more attention under the globally warming environment. In this paper, the mechanism of coal chemical-looping gasification (CCLG) process with copper-based oxygen carrier is analyzed by molecular dynamics (MD) simulation and steady-state process simulation to produce high purity ethylene glycol (EG). Firstly, the effect of temperature and mass ratio of coal and CuO on CCLG process are investigated with gasification experiments. Secondly, the MD simulations in ReaxFF force field are performed in purpose of obtaining the micro-level information and cross-reference with experimental results. Finally, an innovative process to produce high purity EG is designed based on CCLG process from the above simulations and experiment results. The results of gasification experiments show that the optimal reaction temperature is 850°C and the optimal mass ratio of coal to CuO is 1:1.5. The results obtained from the MD simulations are found accordant with the experimental results. The EG targeted CCLG process basically meets the mass ratio required by the production of EG, and the CO 2 emissions of the whole process is only 0.018 kg-CO 2 /kg-EG. [Display omitted]. [ABSTRACT FROM AUTHOR]

In achieving the "double carbon" target, the emission trading system (ETS), as a key market-based emission reduction mechanism, assumes the responsibility of addressing climate change and implementing reform. Most studies focus only on the emission reduction effects of green policy, but weighing the relationship between emission reduction and development is a practical dilemma to be faced. Taking China's pilot ETS as an example, this problem was analyzed using the synthetic control method, and the specific impact channels are discussed. It was found that: (1) Carbon emissions and carbon emission intensity in the pilot ETS areas of Tianjin, Hubei and Chongqing decreased significantly, and economic growth has progressed to a certain extent. Robustness tests basically verified the effectiveness of the policy implementation. (2) The pilot ETS mainly has an impact through the transformation and upgrading, and technological innovation channels, promoting significant improvements in energy structure, industrial structure, energy efficiency and the number of patent applications. This study releases a positive signal for the compatibility of emission reduction and economic development goals at the national level for China's pilot ETS. • The pilot ETS significantly reduced carbon emissions and carbon emission intensity. • The pilot ETS promoted economic growth to some extent. • Transformation and upgrading, and technological innovation are the influencing channel. • The SCM method can synthesize the "ideal" control unit to evaluate the policy effects. [ABSTRACT FROM AUTHOR]

• We model China's emission trajectories under the dual goals by scenario analysis. • China's emission trading scheme (ETS) is simulated through a non-linear programming. • Linking the ETS to dual goals saves emission abatement costs (EACs) by 61.41%–80.33%. • Historical responsibility scheme is optimal for its lowest initial EACs without ETS. • Peaking emissions in 2030 generates more room for economic growth in the next decade. China has committed to goals of reducing its carbon intensity by 60%–65% in 2030 above the 2005 levels and peaking its carbon emissions by latest 2030. While a unified national emission trading scheme (ETS) has been recognized as the crucial instrument to fulfill these ambitious dual goals, its potential performance remains underexplored. This paper quantifies China's need for emission reduction under the dual goals in 2030 by setting three scenarios for peak emissions. Four initial allocation schemes of carbon emission allowance (CEA) are compared according to the emission abatement costs (EACs) of China and its 30 provinces. By estimating the provincial marginal abatement cost curves, China's ETS is simulated through a nonlinear programming aimed at minimizing its total EACs. We find that in achieving the dual goals it makes economic sense to operationalize the ETS that would reduce China's EACs by 61.41%–80.33% in 2016–2030, at a carbon price of 394.55–425.75 RMB per ton CO 2. Peaking China's emissions in 2030 is the preferred choice that will trigger the largest GDP in 2016–2030. The historical responsibility scheme is recommended for the CEA allocation because of the lowest initial EACs without ETS. To allow more room for economic growth after China peaks emissions, there is a need for overfulfilling the goal of carbon intensity reduction by 2030, which is consistent with China's latest climate mitigation targets. This research not only highlights the role of ETS in realizing China's dual goals, but provides a scientific framework for evaluating the environmental policies towards multiple goals in a cost-effective manner. [Display omitted] [ABSTRACT FROM AUTHOR]

Blending hydrogen into the existing natural gas pipeline network is regarded as the most potential transportation mode on the utility-scale. However, the impact of hydrogen on the operation performance of the pipeline remained unclear. This paper analyzes the economic and environmental performance of natural gas pipeline under different hydrogen blending ratios and different hydraulic boundary conditions. In order to reduce the operation costs and carbon emissions in each condition, this paper establish a non-linear optimization model to get the new operation plan of the pipeline system. Further, in order to characterize different boundary conditions of the system, four scenarios, namely, the baseline scenario (BS), the setpoint of flow rate scenario (SF), the setpoint of pressure (SP), and the setpoint of heat flow rate (SH) are proposed in this paper. Two studied cases demonstrated that: (1) the original compressor for natural gas can adapt to a hydrogen blending without change the type of compressor. (2) The optimization model has significant potential in reducing the economic cost and carbon emissions of the system with an average decrease of 11.48%. (3) For every 1% of hydrogen added, the annual operating cost of the system is reduced by $0.73 million (3.29%) in SF, 0.017 million (0.08%) in SP, or increased by $1.67 million (7.50%) in SH. Moreover, the annual carbon emission is reduced by 0.38 kt (3.53%) in SF, 0.047 kt (0.44%) in SP, or increased by 0.76 kt (7.14%) in SH. However, when the hydrogen mixing ratio is more than 8%, the contrary trend may occur. (4) The maximum blending ratio at different points of the multi-source pipeline network are physically interdependent. The paper proposed an optimization model for the 2-E analysis of the pipeline and can provide theoretical guidance for the further application of this transportation mode. • Hydraulic impact of hydrogen on natural gas pipeline is estimated. • Factors that constrain further hydrogen blending are analyzed. • A power optimization model is proposed for the given hydrogen blending ratio. • Pareto set of hydrogen blending are obtained for multi-source pipeline. [ABSTRACT FROM AUTHOR]

• A new fusion research method is proposed to comprehensively optimize CCLG process. • Main reaction conditions are investigated to achieve low CO 2 emission. • Valuable reaction kinetic parameters are explored from microscopic perspective. • The performance of CuO is better than Fe 2 O 3 through eight cycle experiments. Carbon dioxide (CO 2) emission reduction has become an urgent topic to be studied and solved with the in-depth understanding of global warming and frequent occurrence of extreme climate. At present, the application of chemical looping technology in coal gasification to produce high purity synthesis gas is an important way to achieve CO 2 emission reduction, ensure energy security, and promote ecological civilization. In this paper, a new fusion research method combining multi-scale modeling and experimental testing is adopted to comprehensively optimize the coal chemical looping gasification (CCLG) process, aiming at ruducing CO 2 emissions in the synthesis gas production of CCLG. In order to investigate the effect of main reaction conditions on CCLG process, the pyrolysis and gasification experiments of Meihuajing coal are carried out in a tubular furnace reactor with Fe 2 O 3 and CuO as oxygen carriers respectively. Subsequently, the multi-scale simulation of CCLG process including molecular dynamics (MD) and computational fluid dynamics (CFD) simulations is performed to validate the experimental results and supplement important reaction kinetics data. Both of multi-scale modeling and experimental testing suggest that the optimum pyrolysis temperature range, gasification temperature range, char/oxygen carrier mass ratio (C/O), and steam flow are below 900 ℃, 900–950 ℃, 1:1.5, and 0.15 g/min respectively, providing an effective guidance for the optimal design of practical CCLG pilot plant. [ABSTRACT FROM AUTHOR]

In response to resource depletion and tightening carbon emissions policies, the product oil is gradually being substituted by biofuels and faced with falling demand. A large number of studies have been done on the optimization of the biofuel supply chain, but few of them have considered the existing petroleum pipelines for policy reasons. Market-based reforms in the oil and gas industry have provided the possibility of pipeline sharing, whereby pipeline owners can use the remaining delivery capacity to transport other liquid fuels that are allowed into the pipeline, such as biofuels, thereby increasing pipeline benefits and reducing biofuel logistics costs. This paper develops a logistics optimization model considering multi-product pipeline scheduling from the perspective of biofuel suppliers and proposes a pipe-rail transportation mode to assess the optimization potential of logistics costs. Finally, this paper verifies the feasibility of the proposed approach using a logistics system in a region of China as a practical case study and conducts a sensitivity analysis on whether changes in the demand for product oil and biofuels affect the choice of pipeline opening location, concluding that there is no effect within a 4-fold increase in biofuel production and a 0.78-fold decrease in product oil demand. • Propose a method to evaluate the sharing capacity of single-source pipelines. • Develop a logistics optimization model considering pipeline scheduling. • Propose a pipe-rail transportation mode. • Reduce biofuel logistics costs by 8.64% or 8.41%. • Pipeline sharing program will not be affected until biofuels increase 4 times. [ABSTRACT FROM AUTHOR]

The integrated energy system which coordinates natural gas, renewable energy, and other energy subsystems is an effective way to promote a low-carbon economy. An effective framework for system assessment and optimisation is a critical issue. This paper takes a natural gas-wind-photovoltaic integrated energy system as the research object and uses the simulation software to analyse its techno-enviro-economic feasibility. Firstly, a mathematical model is customised to optimise the system installation and operation plans. Renewable electricity replaces some natural gas, resulting in pipeline pressure fluctuation. Here, the Stoner Pipeline Simulator software is used to simulate pipeline network operation to quantify the aforementioned pressure fluctuations. The proportion of renewable energy is gradually reduced until the network pressure fluctuation is less than 20% to ensure the stability of pipeline operation. Then, the optimal operation scheme can be determined. Taking three cities in Shandong, China, as cases, the results show that the proposed system is beneficial for urban energy internet development: (i) the total net present cost is reduced by 19.7%, 19.8%, and 20.8%, (ii) annual CO 2 emission is reduced by 23.7%, 18.4%, and 12.2%; (iii) the levelised cost of energy is 0.142 $/kWh, 0.143$/kWh, and 0.153$/kWh. [ABSTRACT FROM AUTHOR]

As the demand of fossil fuel declines, improving the infrastructure development of fossil fuel supply chain is the efficient way to reduce cost and carbon emissions. This paper analyzes the impact of declining oil demand on the infrastructure development of the oil products delivery system. A mathematical model is proposed to simulate the transportation and storage schemes, and then is generalized to different forms based on four disposal strategies of idle depots and five sub-scenarios of declining demand. The discussed disposal strategies include storage of other fuels, relocation, destruction and to be sold. A comprehensive evaluation system is also formulated to evaluate the utilization efficiency of the transit depots. Finally, the oil products delivery system in Northwestern China is used to validate the proposed method. Compared with the current system, improving the utilization rate of the depot under declining demand sub-scenarios can improve the economic efficiency by 10.6%, 8.9%, 17.3%,21.3% and 21.6%. With the decline in demand, the economy of destruction of transit depot is better than others, while the environmental benefit of storing other fuels is better than other strategies. • A mathematical model simulated the schemes of the oil products delivery system is developed. • A comprehensive evaluation system of depot's utilization efficiency is proposed. • The simulation model is generalized to different models based on four depot disposal strategies. • Different disposal strategies bring different economy and environment effects. [ABSTRACT FROM AUTHOR]

This article is devoted to discussing the feasibility and the optimal scheme to implement an electric-thermal carbon emissions neutral industrial park and perform a 3E analysis on various scenarios. A carbon emissions neutral framework of electric-thermal hydrogen-based containing MILP energy optimisation model is constructed. Photovoltaic power generation, electrolysis hydrogen production are considered in the model. There is an optimal scheme for realising carbon emissions neutrality in industrial parks, which will cost a relatively high price and the compromise scheme which can implement low carbon emissions is also worth studying. The results of the real-world case show that the present value of the cost of achieving carbon emissions neutrality is $ 8.61 billion (109). The scheme presents a compromise between environment and economy will cost $3.95 billion while bringing a 61 % reduction in emission compared with the baseline, which relies upon on-grid and natural gas. And the scheme is most affordable when hydrogen energy accounts for 95 %. Finally, in order to verify the generalisation of the roadmap, the analysis method has been applied to other industrial park cases of typical cities around the world, and the feasibility of achieving the carbon emissions near-neutral goal in these areas is evaluated. • A roadmap covered schemes of compromised low carbon and carbon emissions neutral was proposed. • A carbon emissions neutral framework of an electric-thermal hydrogen-based system is constructed. • An overall 3E analysis method coupled with an optimisation model is proposed. • Scheme to achieve carbon emissions neutral of an industrial park and various scenarios were studied. • Feasibility analysis of carbon emissions neutral cases along with typical cities worldwide. [ABSTRACT FROM AUTHOR]

Distributed energy systems (DES) with hybrid sources has become a more effective way to increase the flexibility of energy supply. Current relevant research on DES design optimization strives to improve system efficiency and sustainability through independent application of subsystem interconnection and demand response. This paper aims to analyze the coupling impact of the above two strategies on the performance of DES. A general multi-objective mathematical programming model is proposed to work out the optimal design and operation scheme of DES, as well as flexible management of electricity, cooling energy, heating energy and steam. The minimum annual cost, carbon emission and energy demand deviation are set as objective functions. Additionally, the augmented ε-constraint method is introduced to search for the trade-off among three indicators. A composite community in China is taken as a case and three scenarios are carried out for comparison. Results reveal that the annual cost and carbon emission are further decreased by 7.3% and 32.1% under the coupling impact of subsystem interconnection and demand response. Eventually, the preferred strategy is analyzed in detailed to illustrate how this coupling strategy further improves the performance of DES. • The coupling impact of subsystem interconnection and demand response is analyzed. • DES is evaluated by economic, environmental and demand deviation indicators. • A tri-objective MILP model is built to determine the optimal coupling strategy. • The AUGMECON is introduced to search for the trade-off between three indicators. • The annual cost and carbon emission are further decreased by 7.3% and 32.1%. [ABSTRACT FROM AUTHOR]