Curb CO2 Emissions Research Articles

CO2 Emissions and Development Indicators: a Causality Analysis for Bangladesh

This paper aims to check the dynamic linkages between CO2 emissions and development indicators (per capita Gross Domestic Product (GDP), population density, and urbanisation) of Bangladesh. Using annual data in IPAT model for the period of 1972–2015, we have applied Johansen co-integration and Granger causality tests to examine the long-run co-integration and short-run dynamics of the concerned variables. The obtained results reveal that there is bidirectional causality between CO2 emissions and urbanisation, and CO2 emissions and GDP per capita for the study period in Bangladesh. This implies that GDP growth and urbanisation process are the major sources of CO2 emissions in the country. Therefore, policy makers should take extreme care in designing and implementing the environmental protection policies to curb CO2 emissions with a desired level of economic growth and urbanization.

What determines the diversity of CO2 emission patterns in the Beijing-Tianjin-Hebei region of China? An analysis focusing on industrial structure change

As the largest CO2 emitter in the world, China is facing significant challenges in CO2 mitigation. In the search for low-carbon development and industrial upgrading, the Beijing-Tianjin-Hebei (BTH) region represents an experimental plot for all of China. In this study, we employed a comprehensive analytical framework to investigate the changing pattern of CO2 emissions in the BTH region, where large-scale industrial structural changes are happening; the results of this study provide a critical reference for regions facing the dual tasks of industrial transitions and environmental protection. The results indicate that industrial structural changes have helped diminish mounting CO2 emissions in the BTH region; however, the extent of the effect differs among the provinces involved. Improvements in technology and organization level in the fastest growing sectors, such as machinery manufacturing and service industries, have helped to curb CO2 emissions significantly. However, industrial structural changes have failed to narrow the CO2 emission gaps among provinces in the region. Being in different phase of development and possessing various resource endowments, the provinces in the BTH region have followed a diversified path of industrial upgrading and have emerged as a region with explicit labor divisions and supply chains. On one hand, this intensifies regional CO2 emission differences, and on the other, it has allowed policymakers to promote more customized decarbonizing plans.

Extended STIRPAT model-based driving factor analysis of energy-related CO2 emissions in Kazakhstan.

Extended stochastic impact by regression on population, affluence, and technology model incorporating ridge regression was used to analyze the driving mechanism of energy-related CO2 emissions in Kazakhstan during 1992-2014. The research period was divided into two stages based on GDP of Kazakhstan in 1991 (85.70 × 109 dollars), the first stage (1992-2002), GDP < 85.70 × 109 dollars, the stage of economic recovery; the second stage (2003-2014), GDP > 85.70 × 109 dollars, the stable economic development stage. The results demonstrated that (1) population scale and the technological improvement were the dominant contributors to promote the growth of the CO2 emissions during 1992-2014 in Kazakhstan. (2) Economic growth and industrialization played more positive effect on the increase of the CO2 emissions in the stable economic development stage (2003-2014) than those in the stage of economic recovery (1992-2002). The proportion of the tertiary industry, the trade openness, and foreign direct investment were transformed from negative factors into positive factors in the stable economic development stage (2003-2014). (3) Due to the over-urbanization of Kazakhstan before the independence, the level of urbanization continued to decline, urbanization was the first factor to curb CO2 emissions during 1992-2014. Finally, some policy recommendations are put forward to reduce energy-related carbon emissions.

CCUS: Solving the conundrum of decoupling sustainable economic growth and CO2 emissions

COP-24 left us with the important legacy of a rulebook for putting the Paris Agreement into practice, particularly in terms of measuring and reporting CO2 emissions. However, countries failed to agree voluntary market mechanisms, and more importantly, the imperative of staying below the 1.5°C of the IPCC report. Globally, in 2017 renewable power contributed to 70% of net additions to power generating capacity with estimated 178 gigawatts added.1 New additions to solar capacity were greater than combined additions in coal, natural gas and nuclear power. However, CO2 energy-related emissions increased 1.4%, primarily due to global economic growth of 3.7%. The UK has successfully managed to curb CO2 emissions by 43% compared to 1990 levels, and therefore, making good progress towards the 80% reduction target by 2050.2 This is especially significant considering that during the same period the UK economy grew by over 70% (above the G7 average). So, have we solved the conundrum of decoupling economic growth and CO2 emissions? Decarbonisation of the power sector with a shift from coal to gas is largely responsible for the UK emissions reduction, with 75% reductions since 2012 coming from the power sector. It is clear, though, that further reductions require decarbonisation of other sectors, particularly heat, industry and transport. The UK Spring Statement 2019 introduced the Future Homes Standard, mandating the end of fossil-fuel heating systems in all new houses from 2025, and this has been met with disbelief in the construction sector. There is consensus that meeting the global climate ambitions of the Paris Agreement without jeopardising economic growth requires that we take a holistic approach to decarbonisation, particularly to incentivise decarbonisation of energy intensive industries.3 For example, existing 45Q tax legislation in the United States provides incentives in reducing CO2 emissions to power plants and industrial facilities and offering tax credits of $50 per tonne of CO2 stored and $35 per tonne for CO2 utilised. It is clear also that policy parity is needed across energy technologies.4 The UK has recently set up the Clean Growth Strategy aiming to grow national income, while cutting CO2 emissions.5 The UK CCUS Cost Challenge Taskforce reported that CCUS can play a critical role in reducing emissions across electricity, as well as heating, industry and transport.3 In addition, CCUS can also improve productivity and competitiveness in a future low carbon economy. It is also clear that a ‘no CCS pathway’ would result in a more costly option to achieve the required targets. For example, for the UK to decarbonise electricity without CCS, it would require low-carbon generation to be more than quadrupled between now and 2050. The deployment of CCUS in industrial clusters can help drive lower costs. These clusters are areas with a number of industrial sites (e.g. chemicals, iron/steel, food/drink, cement, refineries etc) and will benefit from sharing infrastructure as well as knowledge. Industrial decarbonisation is key to achieve the 80% reduction target as around 25% of UK emissions come from industry. The UK Industrial Strategy has set out Grand Challenges to maximise the advantages for UK industry from the global shift to clean growth. This includes establishing at least one low-carbon cluster by 2030 and a net-zero carbon industrial cluster by 2040.6 King Coal's abdication is only a partial fix for decarbonisation of the power sector. It will not solve the conundrum of decoupling sustainable economic growth and CO2 emissions. CCUS does! Prof M. Mercedes Maroto-Valer, FRSE, FIChemE, FRSC, FRSA R. Buchan Chair in Sustainable Energy Engineering Director Research Centre for Carbon Solutions (RCCS) Assistant Deputy Principal (Research & Innovation) Heriot-Watt University

Global Development, Converging Divergence and Development Studies: A Rejoinder

Global Development, Converging Divergence and Development Studies: A Rejoinder

The convergence characteristics of China's carbon intensity: Evidence from a dynamic spatial panel approach

In recent years, China's CO2 emissions have surged as the country's economy has expanded rapidly. Faced with mounting international and domestic pressures, China has made great efforts to curb CO2 emissions. To formulate targeted regional reduction plans, the features and characters of provincial carbon intensity should be carefully evaluated. In this study, the existence of convergence in China's carbon intensity and possible technological factors that may influence the convergence, are carefully investigated by building a united framework and employing dynamic spatial panel approach. The estimation results verify that there is significant spatial correlation in China's provincial carbon intensity. There is also evidence that the three different types of convergence (i.e., stochastic convergence, σ-convergence and β-convergence) exist during the sample period of 2000–2016. Moreover, among the technological factors of conditional β-convergence, indigenous innovation activity is most critical. Not all foreign innovations stem from the inflow of foreign direct investment and trade exert a positive effect on carbon intensity reduction. Besides, it is estimated that the spatial spillovers effects from neighboring provinces are important to carbon intensity.

Policies to reduce CO2 emissions: Fallacies and evidence from the United States and California

Since the 1990s, advocates of policy to prevent catastrophic climate change have been divided over the appropriate economic instruments to curb CO2 emissions—carbon taxes or schemes of emission trading. Barack Obama claimed that policies implemented during his presidency set in motion irreversible trends toward a clean-energy economy, with the years 2008–2015 given as evidence of decoupling between CO2 emissions and economic growth. This is despite California being the only state in the USA that has implemented a specific policy to curb emissions, a cap-and-trade scheme in place since 2013. To assess Obama’s claims and the effectiveness of policies to reduce CO2 emissions, we analyze national and state-level data from the USA over the period 1990–2015. We find: (a) annual changes in emissions strongly correlated with the growth conditions of the economy; (b) no evidence for decoupling; and (c) a trajectory of CO2 emissions in California which does not at all support the claim that the cap-and-trade system implemented there has reduced CO2 emissions.

Investigation of the disruption of algal biomass with chlorine

BackgroundAlgal biofuel has a potential for reducing dependence on fossil fuel while curbing CO2 emissions. Despite these potential benefits, a scalable, sustainable, and commercially viable system has not yet been developed. One of the key barriers is the lack of viable methods for disrupting algal biomass for the separation and extraction of bioproducts. This study experimentally investigated the feasibility of using chlorine as an agent for algal biomass disruption.ResultsChlorine was an effective agent for disrupting algal cell, as demonstrated with cell viability and SEM analyses. For disruption studies conducted using algal suspension at 0.02% solids (0.2 g/L), 90% of the algal cells were disrupted in 6 min at 10 mg/L chlorine dose. Moreover, the results demonstrated that the estimated specific energy requirement, specific cost, and GWP for chlorine were lower than those of the existing methods. The energy requirement for chlorine was 3.73 MJ/ kg of dry algae disrupted, while the requirements for the existing methods ranged from 33 to 860 MJ/ kg of dry algae. The GWP for chlorine was 0.3 kg CO2-eq./kg dry algae, while for the existing methods it varied from 5.9 to 369.8 CO2-eq./kg dry algae. Despite these advantages, it was observed that residual chlorine reacted with and mineralized the cell contents, which is undesirable.ConclusionsFuture research efforts must be focused on eliminating or reducing the reaction of residual chlorine with cell contents. If this challenge is addressed, chlorine has a potential to be developed into an energy-efficient, cost-effective, and sustainable method for algal biomass disruption. This will in turn will overcome one of the technical bottlenecks, and ultimately increase algal biofuel production and reduce dependence on fossil fuel and curb CO2 emissions.

The role of renewable energy technological innovation on climate change: Empirical evidence from China

To develop renewable energy as well as promote China's transition to a low-carbon economy, the government needs to pay attention to renewable energy technological innovation (RETI). Using China's provincial panel data from 2000 to 2015, and regarding the CO2 emissions as the proxy of climate change, this paper identifies the relationship between RETI and CO2 emissions as well as seeks to confirm the role of RETI on climate change. The linear regression model confirms that the RETI has a significant negative effect on CO2 emissions. In addition, considering the disparities of energy structure, the impacts of RETI on CO2 emissions may be distinct. We, therefore, construct a panel threshold model by taking into account the distinct effect of RETI under different energy structure. We find that the effect of RETI on curbing CO2 emissions decreases with the rising of coal-dominated energy consumption structure but in contrast, this effect increases with the growing proportion of renewable energy generation. This paper provides new insight into the relationship between technological innovation and climate change. Based on these findings, some relevant policy recommendations are proposed.

Dynamic Optimization Applied for Modelling and Optimal Control of a Packed Bed Reactor for Chemical-Looping Combustion

Abstract Chemical-looping Combustion (CLC) has recently emerged as a promising technology to curb CO2 emissions. The novelty of CLC resides on its inherent ability of avoid direct contact between the fuel and the air, while producing a highly concentrated CO2 stream. This study presents a dynamic modelling and controllability study that demonstrates the technical feasibility of a fixed bed CLC reactor to produce a constant high temperature air stream during the oxidation stage. The heterogeneous model, which considers mass and heat transport resistances in the oxygen carrier particle and the bulk fluid phase, was validated using data reported in the literature. Also, a sensitivity analysis was conducted to gain insight on system’s behaviour. Furthermore, an optimal control problem was formulated to identify optimal control profiles that can improve the efficiency of this process.

Does environmental regulation affect CO2 emissions? Analysis based on threshold effect model

With the increasing pressure on China to reduce carbon dioxide (CO2) emissions, it is crucial to clarify the effect of implementing environmental regulations and their impact on the region. Many studies have focused on the linear, rather than nonlinear, relationship between environmental regulation and CO2 emissions. The exploration of nonlinear relations is conducive to the in-depth study of policy effects and regional differences of environmental regulations in China. To ensure effective CO2 emission reductions, regional differences in CO2 emissions in China should also be considered. In this study 30 provinces of China were divided into three different regions according to their level of economic development from 2004 to 2015. Taking the energy intensity and foreign direct investment (FDI) as threshold variables, a threshold model was used to examine the relationship between environmental regulation and CO2 emissions. It was found that environmental regulation has a threshold effect on CO2 emissions, with significant differences among the eastern, central, and western regions. Environmental regulations in the eastern region were ineffective for curbing CO2 emissions, while the energy intensity was in the middle and low threshold range. However, FDI had a promotional effect on CO2 emissions. In the central region, environmental regulations reduced CO2 emissions under the influence of energy intensity and FDI. In the western region, environmental regulations could not mitigate CO2 emissions when the energy intensity and FDI were used as the threshold variables. It was concluded that a diverse range of measures for CO2 reduction should be adopted according to the local economic situation.

Do Environmental Taxes Pay Off? The Impact of Energy and Transport Taxes on CO2 Emissions in Transition Economies

Abstract In this paper we investigate the impact of environmental taxes on CO2 emissions in the context of emerging market economies. An attempt has been made to identify what role environmental policy and specific tax policy measures play in understanding the relationship between economic development and environmental degradation. The empirical analysis covers ten Central and Eastern European countries in the period from 1995 to 2015. The latest data on environmental taxes are available only from 1995. We contribute to recent literature in two respects. First, we study this relationship within a dynamic framework in which we take into account the issues of serial correlation and endogeneity in the regressors due to the cointegration relationship. Specifically, we rely on the fully-modified least squares (FM-OLS) estimation technique to model the long-term relationship between income and carbon-dioxide emissions. Second, this paper advances our understanding on the effectiveness of tax policy measures in curbing CO2 emissions, on which we have scarce empirical evidence. The results of this analysis provide rather strong evidence in support of an inverted U-shaped relationship between economic growth and the environment. However, environmental taxes do not seem to be effective in modifying the behaviour of economic agents and in protecting the environment. The results are robust to different models.

Exploring the Potential of CO2-EOR as a Mitigation Strategy in the Colombian Oil Value Chain

CCS is considered a primary strategy to curb CO2 emissions. In many models, CCS is an essential technology to meet the 2C target. Drastically reducing GHG emissions in the oil and gas industry will be needed to reach the 2C target as this industry is one of the five most energy and GHG intensive sectors. The implementation of CCS technologies has been widely studied for the refining stage of the oil value chain. According to Berghout et al., between 80 to 90% of GHG emissions in the refining industry could be reduced using CCS. However, the cost involved for its implementation, make it an unattractive pathway. CO2-EOR is currently a promising alternative to reduce CCS costs, and would be able to produce an oil with low-associated emissions during its recovery. This paper aims to estimate the techno-economic potential of CO2-EOR for reducing GHG emissions in the Colombian oil industry. For this purpose, the supply and demand of CO2 are studied by including the CO2 capture potential of the oil industry, cement, power generation and bioethanol, as well as the storage potential of CO2 through the oil recovery miscible process. The state-owned oil company Ecopetrol S.A. was taken as a case study, which represents the oil value chain in Colombia, with about 70% of crude oil produced and 100% of oil transported and refined in the country. A total of 193 Mt CO2 between 2025 and 2040 could be stored through CO2-EOR. As the projected emissions of the oil and gas industry in Colombia from 2010 to 2040 are estimated at 570 Mt CO2, this is equivalent to a potential 34% reduction in CO2 emissions. This mitigation represents approximately 20% of the total reduction under the INDC target for the period 2025 to 2030.

Structural transformation of manufacturing, natural resource dependence, and carbon emissions reduction: Evidence of a threshold effect from China

Natural resource endowment has a significant influence on manufacturing structure which in turn influences CO2 emissions. This paper investigates the effect of the rationalization and upgrading of manufacturing structure on carbon dioxide emissions in China, based on the perspective of natural resource dependence. The results of the STIRPAT model on provincial panel data of the manufacturing sector from 2003 to 2014 show that manufacturing structure rationalization and upgrading will help curb CO2 emissions, while such effects are restricted by a region's reliance on natural resources. The panel threshold model estimations further indicate that the greater the ratio of industrial output to GDP, the weaker the restricting effect of resource dependence on the emissions reduction of manufacturing structure. These findings reveal that the development strategies of manufacturing structural rationalization and upgrading that aim to reduce emissions depend on the level of a region's resource dependence and industrialization.

Current Emissions and Future Mitigation Pathways of Coal-Fired Power Plants in China from 2010 to 2030.

As the largest energy infrastructure in China, the power sector consumed approximately half of China's coal over the past decade and threatened air quality and greenhouse gas (GHG) abatement targets. In this work, we assessed the evolution of coal-fired power plants and associated emissions in China during 2010-2030 by using a unit-based emission projection model, which integrated the historical power plant information, turnover of the future power plant fleet, and evolution of end-of-pipe control technologies. We found that, driven by stringent environmental legislation, SO2, NO x, and PM2.5 (particulate matter less than 2.5 μm in diameter) emissions from coal-fired power plants decreased by 49%, 45%, and 24%, respectively, during 2010-2015, compared to 15% increase in CO2 emissions. In contrast to ever-increasing CO2 emissions until 2030 under current energy development planning, we found that aggressive energy development planning could curb CO2 emissions from the peak before 2030. Owing to the implementation of a "near zero" emission control policy, we projected emissions of air pollutants will significantly decrease during 2016-2030. Early retirement of small and low-efficiency power plants would further reduce air pollutants and CO2 emissions. Our study explored various mitigation pathways for China's coal-fired power plants, which could reduce coal consumption, air pollutants, and CO2 emissions and improve energy efficiency.

Long-run dynamics of renewable energy consumption on carbon emissions and economic growth in the European union

ABSTRACTThis paper examines long-run and short-run dynamics of renewable energy consumption on carbon dioxide (CO2) emissions and economic growth in the European Union. This study employs cointegration tests, Granger causality tests and vector error correction estimates to examine the direction of Granger causality, the long-run dynamics of economic growth and energy variables on carbon emissions. This study analyses time series data from the World Development Indicators over the period from1961 to 2012. The results of this study support a link between renewable energy consumption, economic growth, industrialization, exports and CO2 emissions in the long-run and short-run. The results support that the sign of the long-run dynamics from the endogenous variables to the CO2 emissions variable is negative and significant, which implies that the energy and environmental policies of the European Union aimed at curbing CO2 emissions must have been effective in the long-term. Furthermore, renewable energy consumption and exports have significant negative impact on CO2 emissions in the short-run. However, industrialization and economic growth have positive impact on CO2 emissions in the short-run. The results suggest that both economic growth and industrialization must have been achieved at the cost of harming the environment. The finding suggests that the increasing consumption of renewable energy tends to play an important role in curbing carbon emissions in the region.

Does financial development improve environmental quality in Turkey? An application of endogenous structural breaks based cointegration approach

PurposeThe purpose of this paper is to investigate the long-run effect of financial sector development, energy use and economic growth on carbon emissions for Turkey, in presence of possible regime shifts over a period of 1960-2013.Design/methodology/approachAlong with the conventional unit root tests, Zivot-Andrews unit root test with structural break has been employed to check the stationarity of variables. The cointegrating relationship between variables is investigated by using the autoregressive distributed lag bounds test and Hatemi-J threshold cointegration test.FindingsThe results confirm a cointegrating relationship between the variables. The long-run relationship between the variables has gone through two endogenous structural breaks in 1976 and 1986. Development of financial sector improves environmental quality whereas energy use and economic growth degrade it. The results challenge the validity of environmental Kuznets curve hypothesis in Turkish economy.Research limitations/implicationsThe study uses domestic credit to private sector as a proxy for development of financial sector. The model can be improved by constructing an index of financial development instead of using a single determinant as a proxy for financial development.Practical implicationsThe study may pave the way for policy makers to capture important environmental pollutants in better way and develop effective and efficient energy and economic policies. This may make significant contribution to curbing CO2 emissions while sustaining economic growth.Originality/valueThis is the only study to examine long-run impact of financial sector development on carbon emissions, using the threshold cointegration approach. Hence, the study is a gentle request to reduce the possible omitted variable econometric estimation bias and fill the gap in the existing literature.

Paper

Paper is a material we know from our day-to-day lives because it is used in newspapers, tissues, packaging, etc. Its web-like structure consists of wood fibres and can be visualised by comparing it to the cooking of a portion of spaghetti that is later served onto a plate. Paper is often associated with traditional materials and production technologies. Brought to life in the second century AD, paper has had a significant role in the history of civilisations, from the Chinese empire through the Guttenberg era up to the current ‘digital age’. It has primarily been used as an information carrier and packaging material. However, the architectural applications of paper have been known since the eighth century AD. Although production technologies and the finish of paper have changed and improved over the years, paper has in fact remained remarkably the same through the centuries. It still has the same composition: cellulose fibres bonded in a wet environment, then pressed and dried. Recently, not only the paper-making industry has undergone change, but other industries, like architecture, electronics, the automotive industry and others, are also receptive to the innovative qualities of paper. Growing awareness of the scarceness of fossil fuels and natural resources, the need to curb CO2 emissions and the necessity of reducing the ecological burden caused by the use of materials such as plastics, foam, concrete or steel is encouraging people to find more environmentally friendly solutions, including the circular economy. Paper and its derivatives can satisfy these needs, although it seems that the golden age of paper is coming to an end. Electronic devices such as smartphones, tablets and e-readers, as well as the growing popularity of electronic media, have taken the place of traditional print media, which has resulted in the paper industry’s decline as the producer of information carriers. However, the paper industry can develop in other directions, e.g. smart packaging, the provision of energy and construction materials, where this renewable and cheap material can make a new start, using and being used along with new technologies and innovations. Sustainable development was first described in the Agenda21 document in 1992 and its appendices, which state that the most important challenges for global policy are improving people’s lives and conserving our natural resources in a world that is growing in population, with ever-increasing demands for food, water, shelter, sanitation, energy, health services and economic security. Moreover, the European Parliament and the Council of the European Union ordered in Directive 2008/98/EC that by 2020, the weight amount of recycled or re-used construction waste must be increased to a minimum of 70%. These challenges can be addressed by renewable resources – reusable, recyclable, available and affordable materials, among other things. One of these renewable resources is paper.

Carbon dioxide emissions from the electricity sector in major countries: a decomposition analysis.

The electric power sector is one of the primary sources of CO2 emissions. Analyzing the influential factors that result in CO2 emissions from the power sector would provide valuable information to reduce the world's CO2 emissions. Herein, we applied the Divisia decomposition method to analyze the influential factors for CO2 emissions from the power sector from 11 countries, which account for 67% of the world's emissions from 1990 to 2013. We decompose the influential factors for CO2 emissions into seven areas: the emission coefficient, energy intensity, the share of electricity generation, the share of thermal power generation, electricity intensity, economic activity, and population. The decomposition analysis results show that economic activity, population, and the emission coefficient have positive roles in increasing CO2 emissions, and their contribution rates are 119, 23.9, and 0.5%, respectively. Energy intensity, electricity intensity, the share of electricity generation, and the share of thermal power generation curb CO2 emissions and their contribution rates are 17.2, 15.7, 7.7, and 2.8%, respectively. Through decomposition analysis for each country, economic activity and population are the major factors responsible for increasing CO2 emissions from the power sector. However, the other factors from developed countries can offset the growth in CO2 emissions due to economic activities.

Scenario analysis of the carbon pricing policy in China’s power sector through 2050: Based on an improved CGE model

In this study, an improved computable general equilibrium (CGE) model is developed, and 13 carbon dioxide (CO2) emission scenarios comprising 1 business-as-usual (BAU) scenario and 12 emission-reduction scenarios are designed to evaluate the effects of carbon pricing policy, which includes carbon tax and carbon emission trading, on CO2 emissions, CO2 emission intensity, output, and energy consumption of China’s power sector during 2010–2050. Results show that carbon tax policy plays an important role in curbing CO2 emissions but does not work very well in optimizing the energy structure in a short term. Carbon tax also decreases output, and the reduction of CO2 emissions becomes significant as carbon tax rate raises. High carbon tax would significantly promote the reduction of CO2 emissions in the long run. The output of the power sector would increase under the single carbon emission trading policy. CO2 emissions will continually reduce when various sectors participate in carbon emission trading mechanism. However, the combination of carbon tax and carbon emission trading is hopeful to reduce CO2 emissions of China’s power sector by 90602.15Mt during 2010–2050 under the CT30ETAA scenario. Therefore, a policy that combines carbon tax and carbon emission trading is suggested to sharply reduce CO2 emissions and help optimize the energy structure.