The challenge of global warming has become a driving force for a global energy transition.The Global Energy Interconnection (GEI) is a modern energy system aimed at meeting the global power demand in a clean and green manner.With the development of clean replacement, electricity replacement, and grid interconnection strategies, GEI contributes to the global temperature control by dramatically reducing the level of energy-related CO2 emissions.This study proposes an integrated framework for analyzing the mechanism of CO2 emission reduction via GEI implementation.The obtained results demonstrate that the total cumulative contribution of GEI to mitigating the effects of CO2 emissions (estimated by conducting a scenario analysis) corresponds to a total reduction of 3100 Gt CO2.The contributions of the clean replacement, electricity replacement, and carbon capture and storage GEI components to this process are equal to 55, 42, 5%, respectively.Using GEI, the utilization of clean energy in 2050 will increase by a factor of 4.5 at an annual growth rate of 4.4%, and the electrification rate will be 2.4 times greater than the current one.

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The scientific understanding of climate change is based on a solid physical-theoretical foundation, and long-term observation and research.By analyzing the accelerated rise of the global climate and its wide-ranging effects on the risk of natural ecosystems and the social economy, and, particularly in view of the stringent targets of 1.5 degrees set by the Paris Agreement to limit global temperature rise, this study contends that climate security has become a new, non-traditional,security issue.The fundamental approach to implementing the objectives of the United Nations Framework Convention on Climate Change (UNFCCC) and the Paris Agreement is to develop clean energy vigorously and to accelerate energy transformation.Furthermore, building a global energy interconnection is emphasized as one of the solutions to promoting energy transformation.

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China’s economic transformation and new growth pattern have significant implications for energy demand and greenhouse gas emissions.Using an extended version of a large computable general equilibrium model of China, we explore alternative futures for the Chinese economy and its energy needs over the period from 2015 to 2030.The simulation results show that encouraging household consumption and accelerating economic transition from investment-led to serviceled growth will boost China’s economic growth.Capping coal consumption will improve China’s energy consumption structure and reduce greenhouse gas emissions significantly.The simulation exercises imply that, with a well-designed policy, the Chinese government can meet the challenges of strong economic growth, lower carbon emissions, environmental benefits, and energy security.Moreover, the Chinese government’s goal of peaking carbon emissions at 2030 is achievable.

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This study modelled projected spatiotemporal changes in global wind and solar resources over land in the 21st century under the RCP2.6 and RCP8.5 climate scenarios using an ensemble mean drawn from 11 Coupled Model Intercomparison Project Phase 5 (CMIP5) models.These models’ performances were verified by comparing historical global near-surface wind speed and downward surface solar radiation over land.Compared to the baseline historical period 1985–2005, the distribution of relative projected changes in global wind and solar resources had great spatial and seasonal discrepancies.Under both climate scenarios, projected wind resources throughout the 21st century presented a decreasing trend in Asia and Europe but an increasing trend in the low-latitude Americas.In comparison, projected global solar resources over land generally showed an increasing trend throughout the 21st century, especially in Europe, eastern Asia,and eastern North America.Moreover, wind resources in the Americas had their most significant decrease and increase in January and July, respectively, while in Asia and Europe the decreasing trend as most prominent in January and October,respectively.The most significant increases in solar resources in the Americas, Asia, and Europe happened in October and July, respectively.Discrepancies between the variation trends of future global wind and solar resources suggest the complexity and nonlinearity of these resources’ responses to future climate change.

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Surface solar radiation research is important for understanding future climate change and the application of largescale photovoltaic systems.We used the coupled model intercomparison project phase 5 (CMIP5) under the RCP8.5 scenario to project potential changes in surface solar radiation, surface temperatures, and cloud fractions between 2006 and 2049 in China, as well as how these changes may affect photovoltaic power generation.The results show that the following.(1) For surface temperatures, the median trends of all considered models show warming in China of 0.05 K/year.The maximum positive trends for all-sky radiation appear in the southeast of China, reaching 0.4 W/m2/year.Cloud cover exhibits a mainly decreasing trend in the overall region of China.(2) The all-sky radiation of most selected regions shows a decreasing trend.The maximum negative value (−0.08 W/m2/year) appears in Qinghai.(3) Compared with the average photovoltaic power output from 2006 to 2015, the photovoltaic power output in western China will decrease by −0.04 %/year, while photovoltaic power output in southeastern China will increase by 0.06–0.1%/year.

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A key design parameter for fixed grid-connected photovoltaic (PV) arrays, the optimal tilt angle, does not only depend on the geographic location but is also directly affected by atmospheric conditions.In this paper, long-term variations of solar radiation (i.e.global solar irradiance, direct horizontal irradiance, diffuse irradiance, and ratios of direct and diffuse irradiance) in Beijing are considered to determine their effect on the optimal tilt angle for a fixed grid-connected PV array.We found that there is a declining trend in global solar irradiance over the past 55 years, mainly caused by the decreased direct horizontal irradiance.In contrast, the decline of diffuse irradiance is not obvious, leading to a considerable decrease in the direct irradiance ratio and consequent increase in the diffuse irradiation ratio.Likewise, the long-term optimal tilt angle shows a downward trend.Compared with the optimum in the 1960s, the optimal tilt angle has decreased by 2° in 2011–2015.These results suggest that the declining trend in the optimal tilt angle is mainly caused by the decrease in direct irradiance ratio, which is highly related to atmospheric conditions.Therefore, the design and construction of PV power stations must consider the variations of atmospheric conditions and solar irradiance to determine the optimal tilt angle.

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There has been great concern in the international community as to whether the Paris Agreement will effectively maintain the average global temperature increase below 2 °C from pre-industrial levels.When the nationally determined contributions (NDC) of the various state parties are added, it is clear that a gap remains.Thus, UNFCCC COP21 called upon all state parties and non-state actors to take additional actions to reduce emissions beyond NDCs in order to eliminate this gap.Against the background of energy consumption transformation and climate governance, Global Energy Interconnection (GEI), which features an innovative combination of advanced technologies such as clean energy, global connectivity, and ultra-high voltage transmission, offers a new option for global prosperity and growth with fewer emissions,lower economic costs, and a safer climate.However, it takes time for the international community to fully recognize, accept,and support GEI and the relevant organizations.Therefore, GEI organizations should take the initiative to reach out to the international climate governance system based on its characteristics of multiple tiers, circles, and poles enabling exchange of technology, funding, and projects in order to win widespread support for GEI and facilitate joint implementation.Only in this way will GEI bring further economic, social, and environmental benefits.

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Under the Paris Agreement, targets implemented for 2100 specify temperature increases well below 2 °C, with an ambitious target of 1.5 °C.China signed this agreement and will support these global targets.The question remains whether they are possible, especially considering the slow progress in recent decades, despite the fact that the Kyoto Protocol implemented these targets in 2010.The Intergovernmental Panel on Climate Change (IPCC) required modeling research teams to analyze possible pathways, policy options, and cost benefit analyses for GHG mitigation.China’s CO2 emissions from the energy and cement industries already accounted for almost 29% of global emissions in 2017, and this trend is expected to continue increasing.The role of China in global GHG mitigation is therefore crucial.This study presents a scenario analysis for China’s power generation against the background of the global 2 °C and 1.5 °C targets.We discuss the possibility of a lower CO2 emission power generation scenario in China in order to evaluate the national emission pathway towards these targets.Our findings suggest that China can accomplish rapid transition in the power generation sector, reaching its emission peak before 2025.This would make the global 2 °C target possible because energy system development is a key factor.Furthermore, the recent progress of key power generation technologies, potential for further investment in the power generation sector, and recent policy implementation all significantly contribute to China following a low carbon emission development pathway.

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Electricity sector, as one of the major emission sources of carbon dioxide (CO2), is responsible for reducing carbon emissions and is a major player that addresses global climate change.In the efforts to mitigate the impacts of climate change over the coming decades, decarbonizing power systems is critical.To achieve this goal, power generation systems need a transition from a high reliance on coal-fired power stations to a low-carbon energy mix.This paper proposes a transition planning method that includes the retirement of coal-fired generators and the integration of large-scale renewable power plants.Hence, transmission systems need to be upgraded simultaneously with the changing of generation mix to ensure system reliability.This paper also considers carbon emission cost and introduces and compares two models, which include carbon trading and carbon tax.Furthermore, issues related to the ramping of renewable power systems that are caused by the large penetration of renewable power generators are taken into account by adding the cost related to the sudden change of renewable generation (ramping cost) in the objective function.The proposed model is demonstrated on a modified IEEE 24-bus RTS system.

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Anthropogenic carbon emissions associated with energy consumption are rapidly increasing.Such carbon emissions are further directly related to global climate change.Thus, reducing carbon emissions to mitigate global climate change has been attracting increasing attention.Energy production and energy consumption is linked by energy networks.The network-constrained energy flow leads to a virtual circulation of embedded carbon emissions.This paper introduces the concept and significance of carbon emission flow (CEF), which helps identify the relationship between carbon emissions and energy consumption.Challenges for extending the CEF from an electricity network to multiple energy systems(MES) are analyzed, and CEF models in both the electricity network and MES are summarized.The distribution of CEF and transfer of carbon emissions are studied using realistic case studies based on the energy interconnection system of Southeast Asia and real-world MES in the Jing-Jin-Ji economic circle.Considering the electricity trade in Southeast Asia in 2050, the results show that significant amounts of carbon emissions are transferred among countries.Approximately 19698 ktCO2 of carbon emissions in Malaysia are attributable to electricity demands of other countries.Conversely, the Philippines and Vietnam would be responsible for additional carbon emissions of 10620 ktCO2 and 42375 ktCO2, respectively.With the CEF model, carbon emissions in different energy sectors can be reasonably quantified, thus facilitating the allocation of emission reduction targets in climate change negotiations and low-carbon policymaking.

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The electric energy system in Indonesia is undergoing with the challenges of fast-increasing electricity demand,carbon constraints, and rising costs.Using our model of the Australian and Indonesian electrical grids (either separately or interconnected) that incorporates operational flexibility in capacity expansion planning, we first show that meeting the projected demand for Java and Bali—the main Indonesian grid, with 100% locally integrated renewables by 2050 would be challenging.However, a submarine high-voltage DC (HVDC) link connecting Indonesia’s Java-Bali power grid to the Australian National Electricity Market (NEM) grid through the Northern Territory would help alleviate this situation, given Australia’s abundant renewable energy resources.Then, our model reveals that the Australian NEM could also profit from additional renewables if connected to the Northern Territory through a ground HVDC transmission line to gather intermittent wind and solar generation, which would be curtailed otherwise if unused by Indonesia through the submarine link.Despite the expensiveness of long HVDC links, the wholesale electricity cost of the integrated 100% renewable Australasia power system could be reduced by over 16%, from $AUD177/MWh with only local renewables to $AUD148/MWh with integrated HVDC transmission.The model retrieved the optimal international HVDC link with capacity of 43.8 GW, and the optimal regional HVDC transmission line with a capacity of 5.5 GW.To the best of our knowledge, this is the first detailed model on power system decarbonisation planning for both Australian NEM and Indonesian Java-Bali power grid considering HVDC interconnections.

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With the development of modern power systems, especially that of the global energy internet, high-voltage, direct current (HVDC) cable power transmission will play an important role in the future.The key problem of HVDC cable power transmission is the need for novel cable insulation materials that have high performance, recyclability, and higher working temperature to replace traditional crosslinked polyethylene.This paper investigates the thermal and electrical properties of polypropylene (PP)/Al2O3 nanocomposites as a potential recyclable HVDC cable insulation material.The developed nanocomposites exhibit excellent thermal and electrical properties with the introduction of Al2O3 nanoparticles.Particularly,the space charge accumulation is greatly suppressed.

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