Response Of Energy System Transformation To The Climate Change Mitigation Targets And Simulation Analysis

Mitigating climate change and ensuring regional equity development is equitable are matters of global concern,the key focus of which is energy system.At present,compared with the research on the relationship between climate change and energy consumption,which has been relatively mature,the research on the response of energy system to different targets of climate mitigation in the future is basically blank.Based on the previous studies,this paper systematically combs the experience and facts of the evolution of energy consumption at different spatial scales such as global,regional and national in the past 50 years.Based on that,by setting four scenarios?CPol,NDC,2?and 1.5??in the future,six comprehensive assessment models?AIM/CGE,IMAGE,MESSAGEix-GLOBIOM,POLEs,REMIND-MAgPIE and WITCH-GLOBIOM?were selected to conduct numerical simulation on different time scales for energy-related indicators at global and regional scales,to analyze and explain the transformation trajectory of energy systems in different scenarios,and to judge trend characteristics and differences,as well as the response of low-carbon indicators.Taking the CPol scenario as the benchmark reference,this paper measures the net energy investment gap of each region under different scenarios based on the assumption that all countries in the world would impose the same level carbon tax under the same scenario and use the same model in 2025 and beyond,and they would take the carbon tax as an important source of energy investment.Meanwhile,it is further supposed that the net energy investment gap of each region will be solved by itself.In order to facilitate the unified comparison of regions with different economic levels,the ratio of energy investment gap to regional GDP is regarded as the contribution index of climate mitigation.Meanwhile,the ratio of regional policy cost?GDP loss value?to GDP and the global proportion of regional policy cost?GDP loss value?under different scenarios are also regarded as the contribution indexes of climate mitigation,revealing the relevant contribution of different development level regions to climate change mitigation from a new perspective.Besides,it further studies and compares the relative contribution of China,the largest developing country,and the United States,the largest developed country,to the future mitigation of global climate change.The main conclusions of this study are as follows:1.Empirical facts on global energy consumption?1?From 1965 to 2018,the global primary energy consumption increased by2.74 times,of which the Asia-Pacific region grew the most,contributing 54.56%to the global growth.The average growth rate of energy consumption in developing countries is higher than that in developed countries,and some developed countries even show negative growth,which partly verifies the energy decoupling theory.Over the past 50 years,the global consumption scale of non-fossil energy and its proportion in primary energy have increased significantly,while the proportion of nuclear energy and renewable energy?excluding water energy?has also increased rapidly.?2?The global per capita consumption of primary energy has increased significantly,but the regional per capita consumption of primary energy in developing countries such as Africa,Asia-Pacific region,Central and South America has been lower than the global average.The countries with high per capita primary energy consumption are mainly oil and gas exporting countries and developed countries.The per capita consumption of primary energy in China has been lower than the average level in the Asia Pacific region before 2000,and lower than the global average before2008.In 2018,the per capita consumption of primary energy in China is only 32.87%of that in the United States in the same period.?3?The global power generation has increased steadily.Coal-fired power generation accounts for the absolute proportion,while the proportion of natural gas and renewable energy?excluding water energy?power generation shows an increasing trend.Except for the Asia-Pacific region,the power generation energy in each region tends to be low-carbon energy which is mainly composed of natural gas.?4?Over the past 50 years,the overall inequality of global primary energy consumption per capita has weakened.From a regional perspective,the inequality of primary energy consumption per capita is relatively small in developed countries and relatively large in developing countries.In fossil energy,the global per capita consumption of natural gas is the most unequal,while coal is the least.The global per capita consumption inequality of non-fossil energy is significantly greater than that of fossil energy.The contribution rate of non-fossil energy per capita consumption to the total Gini coefficient of primary energy per capita consumption is higher in developed countries than in developing countries.2.Response of energy system to different mitigation scenarios?1?Compared with the CPol?benchmark?scenario,the global primary energy supply scale will decrease under different temperature rising scenarios?NDC,2?,1.5??in the future,and this decrease will be more obvious under the stricter temperature rising scenario.In the medium and long term,the proportion of fossil energy will increase in the CPol and NDC scenarios,and decrease in the 2?and1.5?scenario,while non-fossil energy will increase in all scenarios.?2?From a regional perspective,the primary energy supply decrease of LAM?Latin American and Caribbean countries?and OECD90+EU?OECD member countries and EU member countries?in NDC scenario is larger than the global average compared with that in CPol?benchmark?scenario.However,if under the strict temperature rising scenario?2?,1.5??,it will cause an opposite result,in which the decrease of primary energy supply in ASIA?Asian countries,except former Soviet Union,Japan and the Middle East?,MAF?countries in Africa and the Middle East?and REF?countries in the former Soviet Union?is larger than the global average.?3?In terms of global power generation,the primary position of coal-fired power generation will not be changed under the CPol benchmark scenario.Under the NDC scenario,the total global power generation is slightly lower than that in the CPol benchmark scenario,but the absolute amount of coal-fired power generation will not decrease.Under the strict scenario?2?,1.5??,the global power generation will decline to a certain extent in the short term compared with the benchmark scenario,but it will significantly increase in the medium and long term.Besides,in this scenario,the proportion of fossil energy power generation will be controlled at 30%⁴0%in the short term and 1%⁴%in the medium term,while renewable energy will take the dominant position.In the long run,solar and wind power will account for more than 70%of global electricity generation by 2100.?4?In terms of the composition of power generation in each region in the future,the proportion of fossil energy power generation will decrease over time under the CPol and NDC scenarios.By the end of the 21st century,this proportion will still be over 30%,while the total proportion of wind energy and solar energy will not exceed50%.Under the strict temperature rising scenarios,solar energy and wind energy will dominate the power generation in all regions in the medium and long term.?5?The reduction of CO₂ emissions will be larger under the stricter temperature rising scenario.CO₂ emissions will show a sustaining decline trend under the strict temperature rising scenario?2?,1.5??.LAM region?Latin American and Caribbean countries?will achieve zero CO₂ emissions first,while ASIA region?Asian countries except the former Soviet Union,Japan and the Middle East?will achieve zero CO₂ emissions at the last.In the short term,most regions will be mainly affected by energy intensity,while in the medium and long term,they will be mainly affected by energy mix.3.Energy investment gap and policy cost in different temperature rising scenarios?1?Considering the future energy investment gap under the premise of carbon tax,in the short and medium term,the global energy investment gap shows an increasing trend under the strict temperature rising scenario 2??1.5??.The global energy investment gap will reach its peak around 2050,with a gap rate of 47.24%?72.15%?.In the medium and long term,the global energy investment gap is relatively stable.Under the NDC scenario,the global energy investment gap is small,and it will show a decreasing trend in long term.The gap rate of global energy investment is less than 1%in the medium and long-term.?2?From the perspective of regions and its energy investment gap,it is more difficult for developing regions,mainly ASIA,to achieve the target of climate change mitigation.At present,China is the largest energy investor in the world,accounting for about 20.63%of global energy investment,but China's economic development mainly depends on high-carbon fossil energy.Compared with the United States,China's net energy investment in the CPol scenario can basically meet the net energy investment demand in the NDC scenario and the short-term in 2?scenario.In the medium and long term,there is a large energy investment gap in the both countries,but the gap rate of China's energy investment is significantly higher than that of the United States and the global average.To achieve the 2?emission reduction target,from the perspective of net energy investment,China's relative contribution is far greater than that of the United States and the world average level.?3?From the perspective of relative policy cost:the OECD90+EU regions of developed countries only bear about 64%of the global policy cost in the short and medium term under the NDC?Nationally Determined Contributions?scenario;while the developing countries and some emerging economies will always bear about 80%of the global policy cost in the strict temperature rising scenario?2?,1.5??.?4?From the national perspective of relative policy costs,China's contribution to global GDP loss is far greater than that of the United States under the 2?scenario and NDC scenario?medium and long term?.This analysis should lead us to reconsider the division of responsibilities and obligations of countries at different levels of development to mitigate climate change.Based on the analysis above,this paper holds that,if there is no international mechanism to coordinate and help developing countries or regions to achieve the predetermined target of strict mitigation of climate change?2?,1.5??,the relative contribution of developing countries or regions represented by China in the future will far exceed their economic strength,development stage and historical accumulation of carbon emissions.In order to ensure global equity,sustainable development and better achievement of climate mitigation targets,developing countries deserve technical support and financial assistance from developed countries and international organizations for their participation in climate change mitigation.This study will help regions or countries with different levels of development to select effective energy development strategies,provide empirical basis for formulating policies adapt to climate change mitigation,and provide objective arguments for participating in international climate negotiations.