Carbon peak and carbon neutrality in China: Goals, implementation path and prospects

Yo Wng, Chi-hui Guo, Xi-ji Chn, Li-qiong Ji, Xio-n Guo, Rui-shn Chn,Mo-shng Zhng, Z-yu Chn, Ho-ong Wng

a Institute of Geology, Chinese Academy of Geological Sciences, China Geological Survey, Beijing 100037, China

b China University of Geosciences (Beijing), Beijing 100083, China

c Development and Research Center of China Geological Survey, Beijing 100037, China

d Shanghai Jiaotong University, Shanghai 200030, China

e Xi’an Jiaotong University, Xi’an 710049, China

f China Institute of Water Resources and Hydropower Research, Beijing 100038, China

Keywords:

Carbon peak

Carbon neutralization

Energy transformation path

Carbon emissions

Carbon capture and storage

Renewable energy

Climate change

Policy development

China

A B S T R A C T

Climate change is a common problem in human society. The Chinese government promises to peak carbon dioxide emissions by 2030 and strives to achieve carbon neutralization by 2060. The proposal of the goal of carbon peak and carbon neutralization has led China into the era of climate economy and set off a green change with both opportunities and challenges. On the basis of expounding the objectives and specific connotation of China’s carbon peak and carbon neutralization, this paper systematically discusses the main implementation path and the prospect of China’s carbon peak and carbon neutralization. China’s path to realizing carbon neutralization includes four directions: (1) in terms of carbon dioxide emission control:energy transformation path, energy conservation, and emission reduction path; (2) for increasing carbon sink: carbon capture, utilization, and storage path, ecological governance, and land greening path; (3) in key technology development: zero-carbon utilization, coal new energy coupling, carbon capture utilization and storage (CCUS), energy storage technology and other key technology paths required to achieve carbon peak and carbon neutralization; (4) from the angle of policy development: Formulate legal guarantees for the government to promote the carbon trading market; Formulate carbon emission standards for enterprises and increase publicity and education for individuals and society. Based on practicing the goal and path of carbon peak and carbon neutralization, China will vigorously develop low carbon and circular economy and promote green and high-quality economic development; speed up to enter the era of fossil resources and promoting energy transformation; accelerate the integrated innovation of green and low-carbon technologies and promote carbon neutrality.

1. Introduction

The latest Intergovernment Panel on Climate Change(IPCC) report stated that limiting the climate change within 1.5℃ promises to peak carbon dioxide emissions by 2030 and strives to achieve carbon neutralization by 2060. The proposal of the goal of carbon peak and carbon neutralization has led to the goal of climate stability (Ritchie H and Roser M, 2020).The Chinese Government aims to peak carbon emission before 2030, according to the announcement at the 75thUnited Nations (UN) General Assembly on September 22,2020. This event marks the beginning of the climate economy in China, which poses great opportunities and challenges for the upcoming green revolution.

After global industrialization, the average CO2concentration in the atmosphere has reached the highest level in the past million years. Since the climate fluctuates unpredictably, both earth’s ecosystem and human society are in great peril. For the past 70 years, The growth rate of CO2concentration in the atmosphere is about 100 times that at the end of the last glacial period. The global average temperature is also 1.1℃ higher than that before industrialization(World Meteorological Organization and Global Atmosphere Watch,2017; IPCC, 2018; Lenton TM et al., 2019). In the future,mankind will face a series of increasingly serious climate changes and their chain reactions, such as the rise of global temperature, the increase of extreme weather events, the rise of sea level and the destruction of marine and terrestrial ecosystems.

The Chinese Government has shown positive responses to climate change with national strategy ambition and determination in the Climate Ambition Summit. It is a great remission of the US withdrawal from theParis Agreement,and a milestone for the global climate treatment. The goal of achieving the carbon peak by 2030 and carbon neutrality by 2060 introduces the era of climate economy in China (Zhang JT and Zhang L, 2021). A thorough green revolution is forthcoming with opportunities and challenges, meaning a comprehensive reformation in the fields of economy, energy consumption, and infrastructure.

Based on those policies, the authors argued the goal and scientific meaning of carbon peak and carbon neutrality.Whether China can achieve the carbon peak and carbon neutrality is analyzed in four parts, emission reduction, carbon sink increase, critical technology and policy development.Furthermore, the authors concluded the implementation path,prospect, and challenges of carbon peak and carbon neutrality.

2. Goal and scientific connotation of carbon peak and carbon neutrality

China has become the world’s largest carbon emitter since 2006. It produced 10.67×109t of CO2in 2020 which accounts for 30.65% of the global total (Ritchie H and Roser M, 2020).In 2020 September, the Chinese Government announced that it will strive to reach the carbon peak before 2030 and carbon neutrality before 2060. Since then, China has become the innovator and leader in low carbon practices, a lifting spirit and confidence in the international community for the implementation and co-work onParis Agreementand “green recovery” after the COVID-19 pandemic (Wang YW, 2021).Meanwhile, extensive attention was drawn by worldwide researchers and policymakers on the goal and scientific connotation of the carbon peak and carbon neutrality (Zhang YS, 2021).

2.1. Goal of carbon peak and carbon neutrality

World Meteorological Organization (WMO) “The State of the Global Climate 2020” stated that the global concentration of main greenhouse gases (GHG) increased globally in 2020,a second warm year with a complete meteorological record(second to 2016). The global mean temperature increased by 1.2°C after industrialization (WMO, Geneva). The UN approved the United Nations Framework Convention on Climate Change (UNFCCC) on May 9th, 1992, with the ultimate goal being to “control the concentration of greenhouse gases at a stable level.

In September 1977, the Kyoto Protocol, a supplementary provision of the UNFCCC, was approved in Japan. The goal was to “stabilize the greenhouse gas concentration GHG emissions in the atmosphere with an approximate level and to prevent potential damage to human beings from climate change” (United Nations Climate Change, 2021). Specifically,emissions of six greenhouse gases shall be controlled and restricted; those being: Carbon dioxide (CO2), methane (CH4),nitrous oxide (N2O), sulfur hexafluoride (SF6),hydrofluorocarbons (HFC), and perfluorocarbon (PFC). On December 12th, 2015, theParis Agreementwas approved and adopted in the 21stUN Conference on Climate Change(COP21, also known as the Climate Conference in Paris). In total, 178 countries from all over the world agreed in the action to set a long-term goal to “limit global warming to well below 2°C, preferably to 1.5°C, compared to pre-industrial levels” (UNFCCC, 2015).

Hereafter, all countries and regions have proposed their national objectives based on national conditions (Chao QC,2016). Among them, the 2.0°C goal corresponds to the positive balance of CO2emissions (carbon neutrality), and the approximate completion time is around 2070-2080 (2074 being the warning year). The GHG emissions (net-zero emissions) shall be neutralized around 2080-2090 (the warning year being 2085). The 1.5°C goals of carbon neutrality shall be achieved by 2050, and the GHG neutrality shall be around 2060-2070 (the warning year being 2063).

To further cope with climate change, the IPCC published the “Global warming of 1.5°C” in 2018 (IPCC, 2018). Based on the global temperature rise of 1.5°C, this report aims to provide essential information on the influence, adaptation, and mitigation of global warming for each government. In addition, this report is the scientific basis for the UNFCCC 2018 promotion dialogue and the Paris Agreement.

After theParis Agreement, by the end of October 31st,2020, 29 countries and regions including China, the EU, and Canada have proposed their initiatives on carbon neutrality in terms of lawmaking, agreement submission, and policy declaration (Deng X et al., 2021). As the largest energyproducing and consuming country, to fulfill theParis Agreementrequests, “an extensive and thorough revolution of the economic social system” shall be imperative. On September 22nd, 2020, the Chinese government promised at the 75thUnited Nations General Assembly (UNGA) that“China will improve intended national determination and contributions by implementing more effective and constructive policies and measures. The Chinese government will strive to reach the carbon peak by 2030 and carbon neutrality by 2060”. On December 12thof the same year,Chinese leaders announced at the Climate Ambition Summit 2020 that “by 2030, CO2emissions per unit GDP will drop at least 65% compared to 2005”. On October 29th, the Fifth Plenum of the 19thCentral Committee of the Communist Party of China (CCCPC) deliberated and approved the CCCPC’s proposals for the formulation of the 14thFive-Year Plan (2021-2025) forNational Economic and Social Development and the Long-Range Objectives Through the Year 2035, which referred “ahead to 2035, carbon peak will be reached and carbon emissions will decrease, fundamental improvement of ecological environment, achieving the basic goal of beautiful China”, “to enact specific action plans for the achievement of carbon peak by 2030. anchoring to strive to achieve carbon neutrality by 2060”.

The enhancement of energy efficiency can largely reduce the carbon emissions from the industrial flow and product custom. A common misunderstanding of carbon neutrality is that economic growth shall be deprived of the carbon emissions during the process to carbon peak. Proposed two essential simultaneous requirements to achieve carbon peak:(1) The annual carbon productivity shall be higher than the GDP growth and (2) the carbon annual consumption per unit shall decrease larger than the increase of energy consumption.In fact, in the early stage of carbon peak and carbon neutrality proposal, He JK and Ma T et al. investigated the feasibility for China to reach carbon peak by 2030 regarding total carbon emissions, intensity, and per capital (He JK, 2013; Ma T and Chen WY, 2016).

Many researchers simulated the path to reach carbon peak from the regional perspective (Li HM et al., 2020; Qi Y et al.,2020; Yuan XL et al., 2020; Zhu PY and Ling W, 2020),combined with the simulation and exploration path for China to decarburization (Den E et al., 2016; Jiang KJ et al., 2018;Liu Q et al., 2017), it can be deduced the expected time of carbon peak would be between 2020 and 2030. Although model parameters may differ from real conditions, China is capable to advance carbon peak, which was already accepted and recognized by the world. As the Research Group for the Implement Approach of Earliest Peaking Carbon Emissions in China has proposed, “China was already prepared for advancing the carbon peak in both economic and technological conditions, prospectively before 2025, or even earlier around 2022” (Research Group for the Implement Approach of Earliest Peaking Carbon Emissions in China,2017). Still, to reach the carbon peak by 2030, there remain many challenges, and another 30 years afterward for the achievement of carbon neutrality poses great requirements in the transformation of China’s economy, technological innovation, and capital investment. The realization of both carbon peak and carbon neutrality require participants’ brandnew thinking modes and strategic patterns, top-level system designs, and scientific long-term planning. The organic combination of short-, medium-, and long-term goals will help identify the optimal transition pathway.

2.2. Scientific connotation of carbon peak and carbon neutrality

Among countries or regions having officially proposed carbon neutrality or climate neutrality, the majority does not strictly comply with the definition by IPCC. Their definition was simply another expression or different unrevealing for the neutrality objective, confusing the scientific connotation between each country (Deng X et al., 2021). Ambiguity and inconsistency exist in the process of goal setting and restricted gas categories. Therefore, it is of great importance to elaborate on the scientific connotation of carbon peak and carbon neutrality. Practical and realizable goals can guarantee the high-quality development of China’s economy, and therefore construct the human community with a shared future actual and profound meanings (Fig. 1).

Fig. 1. The analytical framework of carbon neutral contents (after Zhang XY et al., 2021)

To understand the scientific connotation in carbon peak and carbon neutrality, the first step is to explore the meaning of “carbon” within. TheParis Agreementmentioned “holding the global temperature increase to a given level”, which means almost zero emission of global GHG, that is to achieve the balance between the emission of GHG entering into the atmosphere and the absorption and removal of these gases.This balance is always defined as “neutrality” or “net-zero emissions”. The already approved goals from each nation or region targeting the emission balance are climate neutrality,carbon neutrality, net-zero carbon emissions, and net-zero emissions (Deng X et al., 2021).

“Climate neutrality”, “carbon neutrality”, and “net-zero emissions” were all pointed out and referred to in the 2018 Special Report onGlobal Warming of 1.5℃ by the IPCC(IPCC, 2018). The “carbon neutrality ” (“net-zero carbon emissions”) was explicitly defined as “at a given time to reach a state of global neutrality between CO2emissions by humans and the global CO2removal by humans” (Wang ZX, 2021).The “net-zero emissions” (“greenhouse gas neutrality”) was defined as “at a given time to reach a state of balance between the human-emitted GHG into the atmosphere and the GHG removed by humans from the atmosphere”.

Furthermore, more rigorous measures shall be formulated if we achieve the “climate neutrality” with “net-effect” by human activities on the climate system. Therefore, the definition of “net-zero emissions” and “climate neutrality”cannot be directly equal due to carbon neutrality. The definition of “carbon” within both carbon peak and carbon neutrality by the IPCC is only limited to the CO2emitted and removed from the atmosphere by human activities, and other GHG not included at all.

As knowledge accumulated and was updated, more and more countries and regions have raised weighted consciousness of “carbon neutrality”. At the 2019 UN Climate Action Summit, the Secretary-General of the United Nations(UNSG) Guterres announced: “the 2050 climate group including 65 countries and EU all promised to achieve carbon neutrality before 2050 ”. According to the IPCC announcement, all countries that participated shall achieve the goal of net-zero carbon dioxide emissions. However, these countries have not explicated their target only confined as CO2. For example, Denmark (Danish Ministry of Climate,Energy, and Utilities, 2019), Portugal (Portuguesa and Environment Portugal and Portuguese Agency, 2019), and Canada (Canada, 2016, 2020) all drew up policies targeting the GHG for carbon neutrality. Most countries developed a different conception of carbon neutrality than the IPCC definition, and their target was extended to GHG that includes CO2.

2.3. Definition of carbon peak and carbon neutrality by China

In strict accordance with the IPCC “Global warming of 1.5°C” report, China’s definition of carbon peak and carbon neutrality is in accordance with the original goal of IPCC.

The definition of carbon peak and carbon neutrality was stated in the “14thFive-Year Plan (2021-2025) for National Economic and Social Development and the Long-Range Objectives Through the Year 2035”. Carbon peak: The total emissions of CO2reach a historical peak in a certain period,and after the peak, the emissions gradually decrease; Carbon neutrality: The total emissions of CO2are offset by planting trees, energy-saving, and emission reduction within a certain period.

Specifically, the absolute CO2emissions shall drop to peak carbon emissions and the carbon neutrality requires “netzero emissions”. After the carbon peak and afterward descent of carbon emissions, deep decarburization shall be achieved around 2046-2060, and in the end, carbon neutrality.

Based on China’s definition of “CO2emissions per unit GDP” (He JK, 2021) and the definition of CO2net emissions,the net emission of CO2is the difference value between“emission ” and “removal”. Therefore, the carbon peak defined by China refers to the peak of net CO2emissions,calculated by deducting the removal of CO2emissions. It can be concluded that China has the consistency of “carbon” in both carbon peak and carbon neutrality, hence scientific,integral, and systematic national strategy regarding carbon emission reduction.

3. Implementation paths for China’s carbon peak and carbon achievement

3.1. Energy transformation path

China is the most energy-consuming and CO2emission entity, and China’s energy consumption and carbon emissions of gross domestic product (GDP) are even higher than developed countries (Su J et al., 2021). In 2020, China’s total energy consumption was 4.98×109t of standard coals,equivalent to 9.9 ×109t of CO2emissions, which was the highest in the world, making up 30.9% of total global emissions. To compare, the US, India, and Russia accounted for 13.9%, 7.2%, and 4.5% of total global emissions respectively. Due to the economic underdevelopment in China, historically accumulated carbon emissions per capita were far lower than in developed countries. China’s emission was 16.4×109t of CO2per capita, and the worldwide average value was 214 t of CO2per capita. Therefore, China’s energy transition to push decarbonization is the main approach to peak and neutralize carbon emissions. China shall develop and rapidly transform energy towards a green and low-carbon direction (Zhuang GY, 2021).

China’s energy-related carbon emission is predicted to peak around 2025 (Figs. 2 and 3), nearly remaining unchanged for the next five years, and will drop afterward. By 2050, the carbon emissions will drop to 2.4×109t and reach net emissions by 2060. Currently, the electrical power and industrial sectors are carbon reduction priorities since they account for 43% and 40% of the carbon emissions from the energy industry, respectively. It is projected that the carbon emissions from the industry and transport sectors will peak before 2025, while electrical power and construction will peak before 2030.

Fig. 2. China’s energy-related carbon emission under carbon neutrality scenario (after Wang LN, 2021)

Fig. 3. CO2 emission trajectories under conventional and accelerated energy transition scenarios in China from 2020-2050 (after Zhang HY et al., 2021).

Unlike developed countries of Europe and America,China’s energy structure was highly dependent on coal. More than half of all electrical production was fueled by coal, and over 70% of power plants were coal-fired plants. Carbon emissions from power generation account for 44% of total national emissions in China (Li J et al., 2021). As electrification advances in the future, power generation will play a more important role in the transition of the whole energy system to low-carbon. Meanwhile, the rapid development of the modern service industry and high-end manufacturing will boost the energy efficiency and cycling economy in each field of national production and life. Since the energy intensity will continue decreasing in China, the estimated annual dropping rate will be 3.8% between 2020 and 2050.

3.1.1. Proportion drop of fossil fuels

(i) Coals

Coal is the most carbon emitted energy source that must be reduced to achieve carbon neutrality. China is the largest exploiter, investor, and consumer party of global coals (Fig.4), and the installed capacity of coal power increases from 195 GW in 2000 to 1022 GW in 2020, up to 50% of global coal-fueled power. Therefore, China is in great demand to largely cut down coal consumption to optimize and transit into a low-carbon and clean structure.

Fig. 4. The volume and global proportion of China installed coalfueled power generation during 2000-2020 (after Li J, 2021).

Coal is a low-cost and irreplaceable energy source for the persisting and rapid growth of national entities. The preparation, competition, and completion period of the coal industry development are all shown in Table 1.

Table 1. Development situation anticipation of China’s coal industry under the background of carbon neutrality.

According to “China Statistical Yearbook 2020”, the total primary energy production was 3.97×109t of standard coal in 2019, where unprocessed coals accounted for 68.6%. The total energy consumption was 4.87×109t of standard coal,with 57.7% coals (Sun XD et al., 2021). As coal dependency drops, the proportion of coals will decline to 42.5% by 2035 and 30.4% by 2050 (Pan YR, 2021).

Under the policy of the Belt and Road Initiative, China’s overseas investment in coals is mainly in India, Southeast Asia, Africa for the past years. From 2013 to 2015, more than 100 ×109US dollars from Chinese enterprises were invested in the non-financial nation-building of those countries, mainly on energy and transportation. Since 2020, the investment from the Belt and Road Initiative was shifted into renewable energy sources. The hydraulic power, coals, and solar power counted for 35%, 27%, and 23% respectively. Still, the coal investment increased from 15% (2018) to 27% (2020).

(ii) Oil

The current oil consumption is approximately 650×106t,but 70% are foreign-dependent. The oil demand will peak around 2025 (Fig. 5) with a value of 730×106t and will drop after peaking for a while. Owing to the development and expansion of the electric vehicle industry, the oil demand will decrease to 310×106t by 2050, with an annual decreasing rate of 3.4%. However, the proportion of oil as raw material will rise to 47.5% (Wang LN, 2021).

Fig. 5. China’s demand for oil under different scenarios (after Wang LN, 2021).

Chinese oil companies shall formulate a sophisticated index system to monitor carbon emissions. In the carbon neutrality strategy path, goals at each stage shall be defined to accomplish key indicators. Meanwhile, companies shall actively implement carbon reduction and carbon offset action plans and explicitly quantify indicators within the action plan.In this way, staged goals in the strategic path will be achieved on time (Si J, 2021). New bonus schemes shall be made to reduce carbon emissions. A partial bonus of executive departments shall be directly decided by the staged task index,and a partial annual bonus of employees is by annual completion of carbon reduction. An internal carbon trading system and price mechanism will be established. Hence the price of carbon will influence policymaking when investing in new projects enterprises.

3.1.2. Proportion increase of non-fossil energy

Natural gas is the cleanest fossil energy but similar to liquid oil. Natural gases are less harmful and environmentally friendly, and the most recommended worldwide energy source to replace fossil fuels. Natural gas releases less carbon than fossil oil when generating the same amount of energy.

In 2018, the absolute annual consumption of natural gases was 272.9×109m³. The consumption increased 17.3% than the previous year, an increment of 40×109m³. Still, natural gas only counts for 7% of primary energy consumption in China, while the global average proportion is 23% (Wang HL,2020). Since coal consumption will decrease, China’s growing demand for natural gas is expected due to its low carbon emissions (Fig. 6).

Fig. 6. Changes in China’s energy consumption structure under the target of 2℃. (Data source: China's long-term low-carbon development strategy and transformation path).

Most of the current renewable energy is transformed into electrical power. The large-scale installed capacity of wind and photovoltaic will lay a great impact on the environment.In 2020, the installed capacity of wind and photovoltaic power counted for 24% of the total capacity, but only 9% generated power.

From 2015 to 2020, China’s demand for electricity increased 33%. 54% of the increased gap for electricity was filled up by non-metallic energy technology. The existing challenges for China’s power grid are low coverage and uneven dynamic distribution of power. In remote areas, the basic power supply still relies on fossil fuels. The proportion of coal-fired power was close to 68%.

For renewable energy sources, nuclear and wind power contributed 5% and 18% of total power, respectively, with corresponding 2% and 17% of the total installed capacity (Lin BQ, 2021). By 2030, China’s total installed capacity of wind and solar power will reach over 1.2×109kW. In the future, the main function of accumulation energy and hydrogen energy is to stabilize energy from large-scale wind and photovoltaic power. In this way, clean electric cars not only will replace oil, but also will be an important infusion to the whole power system.

Notably, China has a great storage capacity of shale gas,and the exploitable amount is 3.157×109m³, occupying 15% of the global total shale gas. The development of shale gas exploitation, although late but was gradually reinforced. The explored accumulation of shale gas storage was 2000×109m³and 69.8×109m³ were already exploited and processed by 2020. China ’s shale gas yield in 2020 was 20.1×109m³,counting for 10.64% of the total natural gas (Yu DF, 2021).

3.2. Path for energy saving and emissions reduction

3.2.1. Zero-carbon energy service

The circular carbon economy was first brought up for the green economy recovery and response to climate change after COVID-19. The concept of a circular carbon economy is a guidance for the international society to create a comprehensive, flexible, and renewable integration of energy systems for carbon neutrality and net-zero emissions (Zhou HC et al., 2021). The Report of 19thNational Congress of CCPC proposed “China will establish a green and recycling economic system, will propel the conservation and recycle of energy to reduce the energy and material consumption, and will circularly link the production system with the living system.”

In 2016, the People’s Bank of China enacted theGuidance on the Construction of Green Financial System, which was the world’s first green financial system published by the government. The development idea of this guidance includes“three functions” and “five mainstays”. The functions are resource allocation, risk management, and market pricing.The mainstay requires the development and completion of a green financial system, supervision and information disclosure for the financial institution, an incentive and restrictive mechanism, a green financial product, and market system, and the international cooperation of green finance.

The existing key problem for China is the lack of a management system for a circular economy, a system for cycle industry and technology innovation, and a social cogovernance system (Wei WD et al., 2021). China’s14th Five-Year Plan for Cycle Economyexplicitly stated, “China will strive to develop circular economy, to guarantee the safety of national resources, and to prompt the carbon peak and carbon neutrality. The key approach to carbon peak and carbon neutrality as scheduled is to construct a modern economic system for the development of low carbon and cycling progress, and to strengthen the capability of sustainable development.”

The core of circular economy is efficient and circulating utilization of resources, the principle is “reduction, reuse and recycle”, and the essential features are low cost, low emissions, and high efficiency. Advantages to develop circular economy are: Reduction of steps for product processing and manufacturing; extension of the life cycle for materials and products; capability improvement of product carbon capture and storage; and reduction of energy consumption and CO2emissions during the process of raw materials exploration, preliminary handling of raw materials,waste treatment of products, and remanufacturing (Fig. 7).

Fig. 7. The sketch of energy improvement in the production of circular economy (after Zhou HC, 2021).

The carbon emissions were effectively cut down due to industrial restructure and restrictions on industries with high energy consumption, high emissions, and high pollution. The amount of scrap steel in 2020 was 260×106t, which can reduce 416×106t of CO2emissions. According to the initial estimation by the China Association of Circular Economy(CACE), during the period of the 13thFive-Year Plan, the comprehensive contribution to CO2emissions reduction from the circular economy was 25% (Fu CH, 2021). In 2020 alone,a total of 2.6×109t of CO2emissions was reduced through a circular economy (Wang HJ, 2021).

3.2.2. Total energy consumption control and industrial structure optimization are the main approaches to reduce carbon emissions

(i) Electrical power

The application of renewable energy in the power industry displays increasing impacts on carbon emissions (Fig. 8).Despite the COVID-19 pandemic in 2020, the development of renewable energy still skyrocketed. Compared to 2019, the contribution to carbon emissions reduction from renewable energy increased by 50% in 2020, at a rate of 45% (Fig. 9).Nuclear, wind, and photovoltaic power are the prime energy generations to achieve China’s transition.

Fig. 8. Total installed capacity and structure of power in China from 2020 to 2060 (Data source: China Energy and Electricity Outlook 2020).

Nuclear power: Nuclear power was already confirmed as one of the clean power generation technologies and will be the main force to achieve net-zero emissions. Until September of 2019, 47 units of nuclear power have been operated for commercial power generation. The capacity of in-service nuclear power was 100 GW in 2020, accounting for 2% of total power. However, long construction duration and large investment requirements of nuclear power cause a low ratio of units are in operation. Due to technology improvement and strategy deployment, a growing proportion of nuclear power is expected in the future.

Wind power: China started early on the research, test, and promotion of wind power. The capacity of wind power was 280 GW in 2020, with a share of 13%. The current wind power plants were mainly installed inland, covering the regions in Northeast, Northwest, and North China. The substantial and rapid implementation of wind power is still challenged by the high offshore cost.

Photovoltaic power: The capacity of photovoltaic power was 253 GW in 2020 with a share of 12%. The transformation rate and cost of solar power are highly dependent on photovoltaic technology. The rapid growth of solar power capacity is a necessity to reach net-zero emissions. Although the proportion of solar power gradually increased, however,they were mainly operated in the Three North Areas.

(ii) Chemical industry

Industries with the most emissions shall be targeted for carbon reduction. The chemical industry is the second source of carbon emissions, close to the pressing of ferrous metals.Effectively implemented measures include improvement on utilizing raw materials, especially for coals, power consumption regulation, CO2recycling and capture as much as possible, and biodegradable materials development.

(iii) Architecture

In August of 2020, Academician Qian Qihu of the Chinese Academy of Engineering pointed out at the 16thInternational Conference on Green and Energy-efficient Building and New Technologies and Products Expo, after COVID-19, the biggest challenge for humans is climate change. Policies properly responding to climate change shall be formulated focusing on green development, ecological conservation, and green ecological city. China’s government shall implement measures to conserve energy and reduce emissions, including industrial structure adjustment, green transportation, building energy conservation, and green construction (Wang YW, 2021).

During the accelerating process of urbanization, experts are expecting an urbanization rate of around 65%-70%, with annual new building areas of 1.5×109-2×109m2. The proportion of the construction industry is anticipated to increase by 50% of total carbon emissions. China is currently in the initial stage of energy conservation and renovation for buildings, hence the annual increase of 2×109m2building areas contributes to the growing carbon emissions.

Big data is an indispensable part of the promotion of smart city construction in China. Much work on energy conservation and emissions reduction has been implemented by the Chinese Government. By constructing a platform to display energy consumption, many valuable data on energy consumption can be acquired as the basis for further analysis of carbon emissions.

3.3. Carbon capture, utilization, and storage path

Carbon capture, utilization, and storage (CCUS) is the technical process for carbon emissions reduction. CCUS can remove CO2from emission sources, or directly use CO2, or store CO2. China is the largest carbon emissions country, and its energy consumption still mainly depends on coal.Therefore, the CCUS technique is the key to achieving carbon peak and carbon neutrality (Wang Y et al., 2021).

Only highly developed CCUS techniques can break through the potential of negative emissions. However, the current situation is not suitable for the extensive promotion of CCUS. The CO2demand in China is not scale-integrated and the foundation on commercialization is weak. The technique is still to be perfected as the current cost of the CCUS technique is 300-900 yuan/t. With insufficient and unspecified policy support, the CCUS always plays a“reserved and conserved” role when competing with other low-carbon technologies. Consequently, the CCUS project is often inadequately funded, which hinders the deployment of project schedules and technology advancement.

CCUS is the main approach for China to achieve carbon neutrality by 2060 and the only technique to utilize fossil fuels in a low-carbon and large-scale way (Zhang X, 2020).Since 2000, several policies and projects have been issued by the Chinese Government to advance the CCUS technique.Examples of those projects are listed in Table 2.

Table 2. Details of selected CCUS and CCS demonstration projects in China (after Mi JF and Ma XF, 2019).

Since 2006, CCUS has been listed as China’s most advanced technology for mid-and long-term technical development, hence extensive funds have been granted by national research. Continual funds have been invested in CCUS since 2006, and research groups have been formed to specialize in CCUS. The CCUS is well-financed in different stages and the entire technical process. The research stage includes free exploration, fundamental research, technical development, and demonstration project, and the technical processes refer to capture, transport, utilization, and storage(Zhang JT and Zhang L, 2021). “Technical Development Route for China’s CCUS Technique” was published in 2011 byChina’s Ministry of Science and Technology Social Development Division and Administrative Centre for China’s Agenda 21. By the end of 2020, a total of 35 demonstration projects of CCUS have been established with accumulated CO2storage of 2×106t (Chen F et al., 2021).

Sinopec has already completed a CCUS demonstration project with a complete process of coal-fired power plants,refinery plant smoke gas, and high-carbon natural gas separation. The annual capture amount was 0.6×106t. After many years of development, the application target expands from low permeability reservoirs to reservoirs with extra-rich water volume and reservoirs at complex fault blocks. The applied field also expands. The exploitation rate of CO2flooding pilots in East China, Shengli, and Zhongyuan Oil fields improved 8%-15%. A thorough technical system was formulated including experiment evaluation, numerical simulation, optimized integration of exploration and storage,sealing and prevention, and safety monitoring evaluation.

3.3.1. Carbon capture

(i) Bio-energy carbon capture and storage (BECCS)

The bio-energy carbon capture and storage (BECCS)technique is a combination of bio-energy and CO2capture and storage to achieve GHG negative emissions. The BECCS technique uses plants’ photosynthesis to transform atmospheric CO2into organic matter. CO2is stored and sealed in plants, which can directly be burned for heat and energy supply. Another path is through chemical synthesis reactions to produce natural gas or hydrogen as high-value clean energy. CCS technique can capture CO2produced during the burning process. Further, CO2is compressed and cooled down, and processed CO2will be transported by ships or pipes. Finally, CO2will be buried and stored in lands with suitable geological structures (Chen C et al., 2019).

The application of the BECCS technique can help China achieve multi goals in coping with climate change, energy safety, and deep emissions reduction. According to the data from the renewable energy notebook, the total amount of bioenergy in 2020, 2030, and 2050 will be 12.08 EJ/a, 14.58 EJ/a, 17.24 EJ/a (Fig. 10) (Fan JL, 2021).

Fig. 10. China’s biomass resources in 2020, 2030, and 2050 (after Fan JL, 2021).

(ii) Direct air carbon capture (DAC)

Direct air carbon capture (DAC) is a major technical measure for closing the carbon cycle and achieving negative carbon emissions (Wang T, 2019). DAC technique is free from the restriction of emission variety and geographic location, which can flexibly comply with the CCUS process(Fig. 11). Lackner first proposed DAC in 1999 to mitigate climate change, and after that, the DAC technique was wildly argued for its application (Lackner K et al., 1999). Nowadays,technical development and integrity push the preliminary exploration and experiment on the DAC technique. For example, adsorbents of alkaline liquids and amine organics have been developed and applied, and Chinese researchers conducted experiments on regenerative absorption techniques based on the wet method. It is concluded that the DAC technique has a sweeping applied potential of carbon reduction and carbon neutrality.

Fig. 11. System process of DAC (after Sutherland BR, 2019).

CO2emissions from millions of small-scale burning fuel devices and billions of transportations will be captured for treatment, effectively reducing the CO2concentration in the atmosphere. Correlational studies have pointed out the key to the DAC technique would be to synthesize absorption materials and equipment with high efficiency and low cost(Zhang J et al., 2021).

3.3.2. Carbon utilization

New technologies of carbon utilization have emerged recently, for example, CO2electrocatalytic reduction synthetic chemicals, and photocatalysis, and “artificial photosynthesis”transforming CO2through photocatalysis and photo transformation. In the application of bio-utilization, CO2can be produced in the form of food and feed, and related industries were already commercialized extensively. Still,other techniques are in the development or demonstration stage. The CO2utilization technique can bring about considerable economic and social values during the reduction process.

(i) CO2-methyl alcohol-hydrogen

Methyl alcohol has two functions of “hydrogen capacity”and “carbon capacity ”, therefore is the optimal choice for solving hydrogen energy and CO2development. CO2is the economic connection between methyl alcohol and hydrogen.Currently, the overall technical level of CO2chemical utilization is at the pilot test stage. Demonstration studies have already been accomplished, including reforming and preparation techniques for synthetic gas, synthetic degradable polymer, synthetic organic carbonic ester. Pilot tests have already been conducted on synthetic methyl alcohol, synthetic polymer polyol, and mineralization.

(ii) Artificial synthesis technique of CO2to starch

Research groups such as the Tianjin Institute of Industrial Technology and the Dalian Institute of Chemical Physics and the Chinese Academy of Science designed an artificial approach for synthetic starch by combining CO2and hydrogen produced by electrolysis. Detailed literature can be found in “Science”.This is the first approach to find a replacement of plant photosynthesis to produce starch, which provides a new technical route to “carbon peak” and “carbon neutrality”. This experiment achievement is still in the laboratory stage, and the research group expressed their next goal is “to continue solving substantial problems in the design and regulation of artificial biosystem to synthesize starch, all while promoting the industrial application of correlated outcome”.

3.3.3. Carbon sequestration

Current techniques for carbon sequestration include (1)geological sequestration. This technique directly conserves and stores CO2in the deep saline layer, depleted oil fields, or aquifers in basalts; (2) CO2Enhanced Oil Recovery (CO2-EOR) technique; (3) CO2Enhanced Coal Bed Methane (CO2-ECBM) technique; (4) oceanic storage.

China has already accumulated practical experiences in CO2-EOR and CO2-ECBM techniques. Still, geological sealup is the technique with the most potential, particularly the deep saline water sequestration technique. The first Chinese oceanic CO2sequestration demonstration project was launched in the Pearl River Mouth Basin of the South China Sea (Fig. 12). This project aims to seal up and store CO2emitted during ocean oilfield exploration into reservoirs at 800m ocean depth. A total of 0.3×106t of CO2was stored annually and with a total of 1.46×106t, that is equivalent to 14×106trees planted or 1×106cars’ CO2emissions (Qu J,2021).

Fig. 12. China’s first oceanic CO2 sequestration demonstration project in the Pearl River Mouth Basin (Source: China National Offshore Oil Corporation).

3.4. Approaches for ecological governance and land greening

China ’s goals for ecological construction and environmental protection are to recover the ecological environment and build beautiful China by 2035 and elevate the ecological culture and fundamentally enhance the national treatment system and modern ability by the middle of the next century. The goals of carbon peak by 2030, carbon neutrality by 2060, and ecological culture construction are inherently the same (Guo YQ, 2021).

3.4.1. Ecological recovery

Since the 18thNational Congress of CCPC, ecological civilization has been incorporated into the “Five-Sphere Integrated Plan”. The idea of ecological civilization is to construct a human community with a shared future and a clean, beautiful world. Since the issue of ecological civilization, breakthroughs have been achieved in the promotion of ecological recovery, protection, repair, and climate change due to fundamental and pioneering works.

Since 2016, 25 projects were successfully launched to solve ecological degradation. Pilot projects were carried out in three stages to protect and recover the ecology of mountains,rivers, forests, cropland, lake, and grassland. Historical problems of the ecological environment of depleted mines have been solved in priority regions, including the Yangtze River, Yellow River, Beijing-Tianjin-Hebei Region, and Fen-Wei Plains. Almost 9000 mines were recovered with total areas of 25000 hectares. In 2020, the “Overall Planning of Major Projects on National Critical Ecosystem Protection and Recovery (2021-2035)” was issued. This overall plan stipulates 9 mega projects and 47 major articles covering the Yangtze River, Yellow River, and coastal regions.

The protection and recovery of “integrated mountain,river, forest, cropland, lake, grassland, and dessert” have been continuously launched by China. Fig. 13 illustrates all comprehensive treatment stations for low-carbon and whole domain coverage. Natural restoration is preferably recommended to enhance the ecological capacity of carbon storage. The protection and recovery treatment focus on proceeding with the ecological recovery of historically depleted mines, and comprehensive treatment of deserts,stony deserts, and water and soil erosion. Nature-based solutions (NbS) show great ecological potential for carbon sequestration, carbon storage, and adaptation to climate change. Natural forces are used to improve the relationship between humans and nature. Properly executing land greening must follow these principles: Paying attention to the influence on carbon sequestration by land use and land cover change;reinforcing the treatment on blue bays; strengthening the ecological corridor construction and biodiversity protection.The carbon sequestration ability is mainly improved through increasing carbon sinks of land and oceanic ecosystem.Forest, grassland, wetland, cropland, and deserts are part of the land ecosystem, while mangrove forests and seagrass beds represent the oceanic ecosystem.

Fig. 13. Ecological protection and restoration projects for mountains, rivers, forests, cropland, lakes, and grassland, with China’s ecological security strategic pattern (after Luo M et al., 2019).

3.4.2. Land greening

(i) Soil carbon sink

Soil is the main carbon sink to reduce carbon emissions and achieve carbon neutrality. In the global carbon cycle, soil stores five times more carbon than that of forests and other vegetation, and three times higher than the atmosphere. Sixty percent of the carbon stored in soils is in organic matter (Xi YG and Chen QH, 2021), hence the carbon storage capacity of soil greatly impacts atmospheric CO2concentration. The organic carbon cycle in the soil contains two links: “Carbon input” by plants sealing up CO2from the atmosphere; and“carbon output” by microorganisms decomposing organic carbon in the soil. Inorganic carbon is mainly stocked in dry or semi-dry soils. The CO2absorption mechanism of soil includes atmospheric transport, carbonate dissolution, and soil water infiltration in the aeration zone. The inverse process will release CO2and form the cycle of inorganic carbon.

A research group, from the Chinese Academy of Sciences Institute of Botany led by Jingyun Fang, analyzed field data from 17090 survey sites and concluded that during 2001-2010 China’s average annual augment of soil carbon storage was 270×106t CO2equivalent (Fang JY et al.,2015;Tang X et al., 2018). Lal, President of the International Union of Soil Sciences, roughly calculated and reckoned that China’s potential for carbon sequestration from 2000 to 2050 would be 40×109-44×109t of CO2equivalent. The potential of organic and inorganic carbon sequestration would be 380×106-730×106t of CO2equivalent/a and 26×106-500×106t of CO2equivalent/a, respectively (Zhou P et al.,2021; Zheng JF et al., 2011). The organic carbon storage in the soil can be increased by improving soil fertility, which can further mitigate GHG emissions. Therefore, increasing the capability of soil organic carbon storage is an important approach for China to achieve carbon neutrality.

(ii) Forest carbon sink

Forests are the largest sink inland ecosystem and the ecological benefits of forests are low-cost carbon sequestration, biodiversity protection, and water conservation.Thanks to the extensive implementation of forestry ecological projects, China’s forest ongoing expansion has lasted for 30 years (Fig. 14), with a coverage rate of 23.04% (Li Y, 2021).

Fig. 14. Forest carbon sink areas in China Data (Data source:China Energy and Electricity Outlook 2020).

Coal enterprises initiatively take their responsibilities in national territory greening. The supplementary to forest carbon sink is through forest planting in barren mountains and deserts. The large growth of forest coverage is benefited from intensive forest planting and vegetation recovery. Newly planted and half-mature forests are the majority of increased forests, and they have great potential to grow flourishingly and store carbon. Compared to 2005, the forest stock volume is expected to increase 6×109m3by 2030, and the total installed capacity of wind and solar power generation will reach over 1.2×106kW.

The authors cannot deny the important role of forests in carbon neutrality. Even so, carbon emissions by human production and living cannot be offset. Improvement of regional carbon storage by forests shall follow the principle of forestation and reforestation, as well as the regeneration and fostering of forests. The most suitable situation shall be chosen for forest planting, and a reasonable logging ratio and tools to be applied for cutting down trees. In addition, fire risk and insect pest hazards shall be avoided to weaken the storage capability of the forest (Li SC, 2021).

(iii) Oceanic sink

The ocean is the largest sink on Earth as more than half of bio-achieved carbon is produced by marine organisms, vastly reducing the atmospheric CO2concentration. Being the world’s largest industry, marine farming is an important component of China’s marine economy.

Macroalgae absorbs sea CO2by photosynthesis to increase oceanic sink. This process can prompt and accelerate the spread of atmospheric CO2into the ocean, and thus it is a great input to increase oceanic carbon sequestration and ecological environmental improvement. The advantages of macroalgae are low cost, high productivity, measurable carbon storage, and cultivated controllability. In offshore areas, the blue carbon industry is formed. Macroalgae farming is a proposed renewable developing pattern for oceanic carbon sequestration (Yang YF et al., 2021). To increase macroalgae carbon sink is a vigorous path to mitigate global climate warming, to reduce GHG emissions like CO2, to blossom marine low-carbon economy, and to achieve carbon neutrality. Furthermore, the implementation of large-scale macroalgae farming can achieve marine negative emissions,and therefore is an effective measure to achieve offshore carbon neutrality in China. Currently, only 0.3% of coastal areas are used for macroalgae farming, and the potential developing space is immense. China’s carbon market is the second-largest market for the global transaction of carbon quota, however still no standard system is formulated for oceanic carbon sink.

3.5. Development pathway for key technology

3.5.1. Zero carbon utilization technology

(i) Hydrogen energy

In 2020 December, China’s National Alliance of Hydrogen and Fuel Cell (China Hydrogen Alliance) was the first to issue “Standard and Evaluation for Low-Carbon Hydrogen, Clean Hydrogen, and Renewable Hydrogen Energy”. Low-carbon and clean hydrogen energy is a crucial measure to achieve carbon neutrality because of their low carbon emissions.

Research shows if the carbon peak was achieved in 2030,China’s annual demand for hydrogen would increase to 37.15×106t (Fig. 15) and renewable hydrogen would be 5×106t/year, with installed electrolytic cells of 80 GW. To achieve carbon neutrality by 2060, the annual demand for hydrogen will increase to 130×106t and end-use energy consumption will take up 20%. 100×106t of renewable hydrogen will be generated, and at least 500 GW electrolytic cells will be deployed in operation (Liu W et al., 2021).

Fig. 15. Prediction of China’s hydrogen energy demand under carbon neutrality scenario (after Liu W, 2021).

To deeply reduce emissions, hydrogen-based industries will be a great option for industries that are difficult to cut down CO2emissions. High CO2emissions industries include steel, cement, synthetic ammonia, ethylene, benzene, and methyl alcohol. To achieve carbon neutrality, low-carbon or zero-carbon manufacturing techniques shall be employed,especially in those industrial sectors with less reduction being done. Hydrogen as the component and raw materials used for most petrochemical products are excellent zero-carbon reducing agents. Therefore, hydrogen will play an irreplaceable role in future industrial deep carbon reduction(Jiang KJ et al., 2021).

(ii)In-situresource utilization of coals

Fifty percent of China’s coals are fueled to generate power, hence, how to utilize coals with high efficiency and low pollution is the key to zero-carbon technology.Underground gasification can transform coals into fuel gases and transport them to the ground, which is the main technique to in-situ fluidized exploit deep coals. China has rich resources in deep coal. Coal buried 1000-2000 m deep is 2.7×1012t, and 1000-3000 m is 3.77×1012t. Currently, deep coal resource buried under 1000 m is affected by ground temperature and rockburst. No technical and financial conditions are available for underground mining. Even so,insitugasification mining of deep coals is the most ideal mining technique (Liu SQ et al., 2021).

Deeplyin-situutilization is performed through underground gasification. Natural gas is the ultimate production of underground gasification of deep coals. This technique has both technical and financial advantages.Underground gasification not only can exploit deep coalsinsitugasification with cleanliness and high efficiency but also can compensate for the natural gas supply gap. The integrated supply of coal, electric, gas, heat, hydro, and oil power can satisfy China’s growing demand for natural gas.

3.5.2. Coupling technology of coal and new energy

(i) Integrated storage of wind, solar, hydro, and fire energy

Coals and renewable energy can complement each other.The integration of coals and renewable energy to generate power can guarantee the fundamental power supply during rush hours; renewable energy sources such as solar, wind, and water-holding power. When the power supply is lacking, coal power will be deployed to fill the supply gap. The energy integration can fund a support base for new energy development. Renewable energy is a great source to neutralize carbon. By increasing the contribution to carbon emissions reduction, the instability of renewable energy power can be avoided, and in reverse can act as an alternative approach to reduce carbon emissions. The new coupled system of coals and new energy will realize the integrated storage of wind,solar, hydro, and firepower, and eventually largely reduce carbon emissions from coal-burning.

The installed capacity of renewable energy is rapidly growing in China. By the end of 2017, the installed capacity of renewable energy will reach 1.7×1012kW·h, and power production will be 1.7×1012kW·h. However, the effective consumption rate of renewable energy is still low. In 2017,unpreserved or unused wind and solar power was 41.9×109kW·h and 7.3×109kW·h, respectively. Therefore, the enhancement of effectively integrating into the power grid and decreasing wind and solar energy waste are key tasks for renewable energy development (Li ZW et al., 2019).

(ii) Biomass energy

Biomass energy technology is an indispensable option for China ’s electric power department in low-carbon transformation. Biomass technology includes biomass power generation, biology liquid fuels, biogas, solid fuels, bio raw materials, and chemicals (Fig. 16).

Fig. 16. Boundary sketch of power generation technology by different biomass resources (after Li J, 2021).

“Bluebook for the Development Potential of 3060 Zerocarbon Biomass Energy” was published by the China Association for the Promotion of Industrial Development Biomass Energy Branch. China’s current yearly production of major biomass resources is 3.494×109t. Among them, the development potential for energy utilization is 460×106t of standard coals. It is expected by 2030 the total biomass resources will reach 3.795×109t, and 5.346×109t by 2060. By 2030, the utilization of biomass energy will reduce over 900×106t of carbon emissions, and 2×109t by 2060 (Deng Y,2021).

Direct-fired power is the main biomass energy in China.The technical start-up was late but rapidly developed, and the total installed biomass capacity is second only to the US. By the end of 2017, China’s total capacity of grid-connected biomass power was 14.762×106kW. Agriculture and forestry grid-connected power accounted for 7.009×106kW, power production through household waste burning was 7.253×106kW, and biogas power production was 500000 kW (Ma LL et al., 2019).

3.5.3. CCUS Technology

The core of carbon neutrality is to reduce or even remove CO2emissions. CCUS/CCS technology can help achieve the goal of carbon neutrality, while the related carbon industry is emerging. CCUS technology includes carbon capture,utilization, and storage. CCUS deprives CO2of emission resources, or directly utilized, or stored CO2to reduce carbon emissions (Zhang X, 2020).

CCUS (carbon capture, utilization, and storage)technology targets GHG emissions reduction. The goal is to largely reduce GHG emissions produced by fossil fuels.CCUS comprehends four steps of CO2capture, transportation,utilization, and storage. The coverage of CCUS technology is extensive that covers key technologies from deep saline water sequestration, CO2driving agent of oil displacement, and CO2driving replacement of coalbed methane.

To advance the 2ndgeneration carbon capture technology of coal-fueled power plant, demonstrated and operated commercially by 2030, policy support and financial investment shall increase. Meanwhile, pre-combustion treatment is still a new technology. Electrical generation is high-cost while technology investment shall be accelerated.Restricted by the current level of CCUS technology, one-time energy consumption will increase 10%-20% or even more when deploying the project (Xing LR et al., 2021). The energy loss that hinders the promotion and implementation of CCUS technology is immense. The next generation of carbon capture technology shall focus on the innovation of materials,the improvement of the process, and equipment to breakthrough. Take, for example, the non-aqueous solution from Ion Engineering, the membrane separation system from MTR, KS-21 solvent from Mitsubishi Heavy Industries, and the rich and poor solution absorption regeneration cycling technology from Lind-BASF (Zhao ZQ et al., 2021). These achievements will reduce the investment and operation capital and enhance carbon capture efficiency.

By solving key technologies in each process, China pushes to apply the commercialized 2ndgeneration carbon capture technology by 2035. The goal is to commercially popularize these new technologies and extensively develop integrated full-chain demonstration projects. China is striving to establish 3-5 CCUS full-chain demonstration projects with a million-ton scale during the “14thFive Year Plan” period,and a CCUS industrial promotion center with a scale of 10×106t by 2030 (Zhang X, 2020). By 2050, through CCUS technology, China’s CO2reduction in electric and industrial fields will reach 800×106and 600×106t/year, respectively(Xing LR et al., 2021).

3.5.4. Energy storage technology

Energy storage is the supporting technology for “five major pillars” in the 3rdindustrial revolution. The National Economic 14thFive Year Plan stated to reinforce the link between source grid and charge storage, to enhance the consumption and storage capacity of clean energy, to accelerate the construction of pumped storage power stations,and the extensive application of new energy storage technology. More requirements for energy storage are emerging in the process of restructuring energy resources.Renewable energy is the main source and fossil fuel is the alternative source. Meanwhile, power battery technology develops on a large scale.

Until the end of 2020, a total of 35.6 GW of energy storage projects has been operated in China, and 3.2 GW was the newly-added capacity, increased by 9.8% from a year ago.The capacity of pumped storage power accounts for 89.3% of the total capacity. Proportions of electrochemical and fuse salt heat storage are 9.2% and 1.5%, while compressed-air storage is only 0.03% (Fig. 17). China’s National Development and Reform Commission published the “Guidance on Promoting the Development of New Energy Storage System (Exposure Draft)”, and the guidance stated that by 2025 the installed capacity of new energy storage will reach over 30 GW; by 2030 market of new energy storage will be fully covered; and by 2060, new energy storage capacity will reach over 420×106kW and the nationally total installed capacity will be 750×106kW. The market of new energy storage will be a trillion scales(Table 3), therefore being a great development potential for energy storage.

Fig. 17. Total scale of China’ s energy storage market (after Chen HS, 2021).

Table 3. Development route of energy storage technology in China.

3.6. Pathway of policy development

The achievement of carbon peak and carbon neutrality cannot separate from government policy support. The Chinese government is the leader, supervisor, and policymaker in the action of carbon neutrality (Wang C and Zhang YX, 2020).The goal to achieve carbon peak and carbon neutrality shall be incorporated in the plan of the national economy and social development, and mid-to-long term projects and plans shall be organized in phases. Since the September of 2020, China has released dozens of policy documents to support the carbon peak and carbon neutrality goals, and the national and local media also delivers topics related to that, so that public awareness was largely raised. Besides, China invested a large amount of money to implement the carbon peak and carbon neutrality goals. For example, China has set up a 200×109RMB special funding to support clean coal and high efficiency use, including green and smart extraction, cleaner production and manufacture, efficient utilization, clean combustion and heat supply, household heating,comprehensive coal utilization, and coal bed methane development (Lu, 2021).

3.6.1. Complete market/policy agenda

Management of the carbon cycle is the key challenge of climate protection. To achieve carbon peak and carbon neutrality as soon as possible, a complete agenda of market management and policy is highly required, especially in the key process of energy transformation, energy-saving technology, carbon capture and utilization technology, and carbon sequestration technology. Under the general framework of “carbon management”, implemented measures shall include a series of carbon reduction and removal work on reduction, capture, transportation, storage, and utilization.

Even though China already has the essentials to achieve carbon neutrality by 2060, even higher and more precise requirements are raised due to limited time and tough tasks,an adjustment in each industrial structure, alteration of production method, and every aspect of human living. The government shall formulate more sophisticated management policies in every possible aspect, and spare no effort in the function of guiding, relocating, and restraining.

(i) Legislative measures can legally guarantee China to achieve carbon neutrality. Legislative measures are the legal basis to continuously and effectively support carbon reduction policies and reinforce executive power. Based on legislation,a “sweeping approach ” is avoided when completing the regulations on climate change. Considering regional variation on development degree and economic circumstance, carbon reduction policies shall be issued according to local conditions. In some regions, people’s livelihood still highly relies on the production and consumption of high-carbon energy resources. When reducing carbon emissions, local social policies shall be at least guarantee basic living.

In addition, radical and irrational measures unfit to local conditions on carbon reduction must be avoided to achieve the“carbon peak ” and “carbon neutrality ” goals. Sharply reducing the yield and consumption of fossil fuel energy such as coal and oil or gas, shall not be the competition of carbon reduction. An energy deficit will hinder economic development if the energy transition is abrupt or fossil fuel investment is inadequate (Liu MP, 2021).

In 2021 September, Tianjin issued “Tianjin Regulations on Promoting Carbon Peak and Carbon Neutrality”, which was China’s first regulation on carbon peak and carbon neutrality. This regulation further explicates the action on promoting carbon peak and carbon neutrality across the city also stipulates the reward and punishment mechanism of related behaviors. It is called a system guarantee for carbon peak and carbon neutrality.

(ii) Adaptation policy can support the development of CCUS/CCS technology. Current CCUS/CCS technology is still underdeveloped and refers to CO2capture, transportation,and storage. CCUS/CCS project is not widely recognized and accepted by enterprises and the public due to technical unreliability and overspending. Therefore, adaptation policy shall be made by the government to support enterprises and research institutions to increase investment and study in related fields. Market competitive capability can only be enhanced when enterprises are encouraged to invest more.

3.6.2. Industry standards establishment

Technology is the ultimate tool to achieve carbon neutrality. Enterprises are subject to technology and direct sources of carbon emissions. To achieve carbon neutrality,more rigorous standards regarding carbon emissions shall be issued to restrict enterprises, or more expensive to emit carbon.

The prospect of carbon neutrality will bring policy risk for investment and construction in projects with high emissions and long periods. To reduce the commercial attraction and financing ability of such projects can indirectly provide favorable conditions for the investment and promotion of lowcarbon technology. Therefore, the government shall perfect the industrial emission standard and formulate a carbon tax mechanism. In this way, the carbon emission permit transaction market in each industry will be complete and the green financial system will be constructed. There will be policy guidance and support for enterprises to develop carbon reduction technology. By reducing the transformation cost and fund access difficulty, enterprises can achieve transition with fewer expenses.

Currently, China ’s “Regulation on National Carbon Emission Trading Scheme (Pilot Rules)” (Exposure Draft) is open and available for public advice, and the next stage will be accelerating the formulation of related rules and completion of hardware facility. The final purpose is a substantial operation of the national carbon market.

3.6.3. Trading mechanism for carbon emission rights

China’s carbon market will be constructed within two stages of local carbon market pilot and national carbon market development. In 2005, China participated in the European carbon trading market and benefited from it. The first phase started in 2013. The carbon market pilot program was launched in seven cities and provinces, including Beijing,Tianjin, Shanghai, Chongqing, Guangdong, Hubei, and Shenzhen. Later on, Sichuan and Fujian were added to the program.

The second phase started in 2017. China’s carbon emissions trading market began in the power generation industry. China National Development and Reform Commission issued the “Plan on National Carbon Emissions Trading Market Construction (Power Generation Industry)”,which marks the national carbon emission trading. In 2020,China’s Ministry of Ecology and Environment issued the“2019-2020 National Carbon Emissions Trading Total Quota Design and Distribution Implementation Plan (Power Generation Industry)”.

China’s carbon market extends from pilots into full implementation. First, the “door” for the national carbon market has been opened in major industries, which is beneficial with enormous CO2emissions. Key industries will trade carbon emissions through carbon market supply and demand relation, pricing mechanism, among different bodies market distribution of carbon emissions right, to reach the optimized resources allocation goal.

The current implementation of the carbon market still faces problems and challenges. For example, a function of main body relations in the operation of the carbon market is still undefined; fair and effective approved budget allocation needs to be perfected; various regulations and accessory systems to support the carbon market need to be established.These existing problems will affect the activity level of quota suppliers and demanders whether trading or not in the carbon market, the trading volume, and finally the emissions reduction (Weng ZX, 2021).

3.7. Ten actions for China to realize the vision of carbon peak

The above six paths for China’s carbon peak and carbon neutralization involve four main aspects: Emission reduction(energy transformation path, energy conservation, and emission reduction path), increase carbon sink (carbon capture and storage path, ecological restoration and land greening path), key technology development path (zero carbon utilization, coupling between coal and new energy,CCUS and energy storage technology), and policy development path. These paths basically involve all aspects of China’s social and economic development. As a large manufacturing country and the largest developing country,China’s industrialization and urbanization are still developing in depth, and energy consumption will still maintain rigid growth. Under this background, the Chinese government has put forward goals such as increasing the proportion of nonfossil energy consumption, improving energy utilization efficiency and reducing carbon dioxide emissions. These goals are fully in line with the objectives and requirements of the Paris Agreement, It reflects China’s greatest ambition to deal with climate change. In order to smoothly promote the peak of carbon dioxide emissions, the Chinese government issued the action plan for carbon peak by 2030 in October 2021, which puts forward ten actions for China’s carbon peak(Table 4).

Table 4. Top Ten Actions for China's Carbon Peak.

4. Objective prospects for reaching carbon peak and carbon neutrality

Carbon neutrality is the consensus goal for the world to respond to climate change, but still, many challenges remain:(1) Global total CO2emissions are immense, and the average CO2concentration in the atmosphere has continuously increased; (2) challenges remain in the energy transformation as global energy consumption structure is still dominated by fossil fuels and the proportion of new energy is low; (3) the change of new energy development faces challenges as new energy, such as solar and wind powers have drawbacks of intermittence and spatially distributed diversity; (4) expenses of hydrogen, CCUS, and energy storage technology on the technical application are high, and these energies are still hard for large-scale commercial popularization and application(Zou CN et al., 2021). However, carbon peak and carbon neutrality are the major practice of global green low-carbon renewable development. In the future, China will progressively establish its own “Carbon Neutrality Study ”based on earth system science. The study will cover energy science, and the focus will be the interaction and coevolution of the earth, energy, and human being. China will form a new energy system named “new energy and intelligent energy”.Targeting carbon neutrality, the core of this new energy system will be cleanliness, carbon-free, intelligence, and high efficiency (Pan SQ et al., 2021). Furthermore, a technical system will be formed covering the entire and related process of CO2emissions, capture, utilization, storage, and removal by human activities.

4.1. Carbon reduction

CO2reduction is a necessary approach to achieve carbon neutrality (Zhang QB and Zhou QF, 2021). The IPCC reports that human CO2sources are from fossil fuels and land-use change. 43.2% of CO2is preserved in the atmosphere, 27.9% is absorbed by the marine ecosystem, and 28.9% by the terrestrial ecosystem (IPCC, 2013). To support and achieve the “double carbon ” goal, China will spare no effort in developing a circular economy in the future, focusing on the idea of high-frequency power, and dedicating it to the energy transition.

4.1.1.Advocationofenergy-savingandefficiency improvement and promotion of energy consumption rigid saving and high efficiency

The priority to achieve CO2emissions reduction and the “double carbon” goal is to pinpoint “energy conserving is the first energy resource”. Rigid or mandatory energy conservation and high efficiency of energy consumption is prompted through measures on energy-conserving of consciousness, structure, technology, and management.Effective measures include: Promotion of national energy conserving initiatives; adjustment of industrial energy structure and elimination of industries with high emissions;acceleration of energy-conserving technology and equipment development, deep integration of new generation digital technology, information technology, and energy industry, and energy efficiency improvement through technical innovation;completion of regulations on energy saving and efficiency,increase of rewards and punishments, and guarantee for longterm stable operation of energy-saving and emissions reduction management (Zou CN et al., 2021).

4.1.2. Largely developing carbon circular economy and promoting green and high-quality economy development

Regarding China’s current basic national condition,focusing on the future development, green cycling low-carbon development idea, and the pathway are the inevitable options to achieve the development of a high-quality economy and response to climate change. Zhou HC (2020) stated carbon cycling economy is a “window” to cope with climate change.Wang MY et al. (2017) considered “low-carbon cycling economy is an organic combination of low-carbon economic pattern and cycling economy pattern”. Therefore, carbon economy, cycling economy, and low-carbon economy cannot be treated equally. The circular economy emphasizes the cycling utilization of materials, low-carbon economy focuses on maximized and alternative energy utilization. But it is an organic extension of the development idea for the circular economy, the same purpose as a low-carbon economy.Therefore, special materials such as CO2are concentrated to reduction and resource utilization, to develop carbon cycling economy, with the main purpose being to complete the regular circulation of carbon, to preserve the balance of carbon source and carbon sink, and carbon emissions and carbon utilization. This is the exact definition connotation of carbon neutrality by IPCC.

To develop a carbon circular economy, the relation between its nature and other elements shall be precisely located. The first is to understand the basic attribute of a carbon circular economy. Zhou HC et al. (2021) state that the carbon cycle is systematically integrated, spatially and temporally phrased, and highly efficient with a low amount of carbon produced. System integration refers to the integration within the framework of green development. Carbon circular economy is the core of system integration. The green and low carbon society is the carrier and support to efficiently and environmentally friendlily utilize clean and green energy resources. People living in the society shall follow the systematic principle of green and low carbon as overall a green and low-carbon culture will be framed. Second, the relationship between low-carbon and development shall be accurate. “Low-carbon” and “development” are not simply syntagmatic. Instead, they reinforce and support each other.The balance between “low-carbon” and “development” needs to be balanced properly.

To achieve green and efficient economic development, we should also accelerate building a green financial innovation system. In January of 2021, the People’s Bank of China first proposed that “We will implement major policies and plans to carbon peak and carbon neutrality and will improve the policy framework and mechanisms for green finance”. Hereafter,green finance will play its role in promoting low-carbon development, sustainable development, and ecological civilization. During the 14thFive-Year Plan period, China will continue improving infrastructure on green and low-carbon technologies with the goal of carbon peak and carbon neutrality (An GJ, 2021). Green finance will sustainably evolve if carbon markets are promptly constructed, and opportunities for the green industry are tightly seized.

4.1.3. Accelerating the fossil fuel era and promoting energy transition

The fundamental reason for China’s large total carbon emissions is the massive consumption of fossil fuel energy,mainly coal and oil. Therefore, the utilization of fossil fuel resources is an inevitable choice to respond to the goal of carbon neutrality and to promote industrial transformation.The realization of carbon neutrality will reveal a significant transformation from fossil fuel energy to fossil fuel resources.

In 2018, the industry was still the main energy source in China, according to the industrial proportion of energy consumption (Zhang ZY et al., 2021). Therefore, key approaches to reducing industrial energy consumption are to adjust industrial structure, break through technical problems,improve energy efficiency, and develop industry towards a high-end and green direction (Yuan XL et al., 2020). Building operation and transportation energy are also important sources of energy consumption and emissions. The effective ways to change the current situation are to adopt the concept of optimal house design, to apply low-energy building technology, to develop clean energy and new energy vehicles,and to create intelligent and information transportation (Lin D et al., 2019; Litz P and Tu JJ, 2020; Lu Q and Wings H,2007). In China’s energy structure, coal has high unit energy consumption and accounts for a significant proportion of total energy consumption. Referring to Germany’s energy transition route “Coal Phase-Out”, critical steps for China to get rid of coal dependency shall include phasing out coal,promoting the transformation of outdated mining areas,advancing the modernization construction of electric power systems, and exploring distributed and renewable technologies for energy storage.

Scientific and technological innovation and progress are the driving forces for China’s energy transformation since the innovation and progress of energy technology will directly affect the industrial structure, energy intensity, and energy price (Zhang QB and Zhou QF, 2021). Currently, coal resource utilization is mainly through the coal chemical industry (Wang JL and Wen L, 2021). However, problems such as high cost, low efficiency, and large emissions also arise successively in the practice of the coal chemical industry. In the long run, the coal chemical industry will eventually be replaced by a better technique of resource utilization, and the promotion of coal resource utilization in the future will rely on quality-based utilization. A research group, from the Tsinghua University, explored and optimized systems and processes for producing oxygen-containing organic compounds from CO2and coal (Wang TF et al.,2021). Synthetic hydrocarbons can further be broken down to produce hydrogen. Calculating based on China’s current coal consumption, this method can produce at least 150×106t of H2every year, equivalent to a yield of 200×106t/a from coalhydrogen conversion. When 1 t of hydrogen is converted from coal, 11 t of CO2will be produced. Accordingly, 2.9×109t of carbon emissions will be reduced through this new hydrogen method. New technologies for petroleum utilization are also emerging. For example, DCC-PLUS catalytic cracking technology by Sinopec can greatly reduce energy consumption (Cai JC and Wan T, 2019). Chen JJ and Wei F succeeded in reducing the yield of petrol and diesel to an extremely low rate by improving experimental conditions(Chen JJ and Wei F, 2020). Large-scale resource utilization of petroleum is possible if the improvement is applied in catalyzer, reactor, and single-pass yield of chemicals.

4.1.4. Promotion of clean energy and optimization of energy structure

Non-renewable energy cannot solely serve as the energy supply chain as they are finite resources. Otherwise,permanent damage to the ecological environment will be inevitable, or even worse wars will be started to compete for resources. Therefore, it should vigorously promote and develop clean energy. The current energy structure shall be optimized to reduce fossil energy dependency. Renewable energy and zero-carbon technology are excellent replacements for fossil energy consumption. Renewable energy includes wind, solar, ocean, and geothermal energy, and zero-carbon technology refers to hydrogen, new material energy storage,intelligent energy, nuclear energy, and controlled nuclear fusion.

Guided by carbon peak and carbon neutrality, China’s natural gas market has a bright prospect in the future. In 2017,the “Strategy for Energy Production and Consumption Revolution (2016-2030)” (National Development and Reform Commission and National Energy Administration, 2016)pointed out by 2030 China will confine the total energy consumption below 6×109t of standard coal, and natural gas will contribute to 15% of energy consumption. According to the “Global Energy Outlook 2020” by International Energy Agency (Agency, 2020), China’s natural gas consumption will continue growing for the next 20 years, driven by changing coal to natural gas in industrial electric power.Therefore, in the 14thFive Year Plan, the development of natural gas should focus on the systemically integrated construction of production, supply, storage, and marketing chain. A firm supply system of natural gas shall be established with both domestic and overseas sources. The natural gas supply must adhere to the principle of “domestic first and multi-source import”. In the storage and transportation construction of natural gas, priority projects of the natural gas pipeline network stated in the 14thFive Year Plan are the state-level trunk pipeline, regional pipeline network, and gas storage. Since the 13thFive Year Plan, China has established a market system of “X+1+X ” and a market structure with diverse competition. During the 14thFive Year Plan period,the responsibilities for peak regulation and supply will be clearly assigned. Relevant rules and standards will be formulated regarding the construction and operation of the pipeline network. Regional monopoly shall be forbidden when promoting local reformation of pipeline networks (Zhou SH et al., 2021).

In the future, China will continue the development pathway of ecology first, green, low-carbon, and intelligence.The energy consumption structure will further be optimized.On one hand, clean and efficient utilization of fossil fuels,such as coal, will persistently be advanced, while on the other hand, individual supply capability of oil and gas resources will be further improved.

4.2. Increasing carbon sinks

Emission reduction and carbon sink increment are two fundamental paths to achieving carbon neutrality. In the general layout of China’s ecological civilization construction,the ecological capability of carbon sequestration is required to improve. The increase of ecological carbon storage is through national territory planning and control, effectively expanding the storage of forest, grassland, wetland, ocean, soil, and permafrost.

Carbon sink refers to the ability of forest and grassland to absorb and store CO2(Zhang XF, 2019), compromised by terrestrial and marine carbon sink. A terrestrial carbon sink is called “green carbon” that green plants absorb atmospheric CO2through photosynthesis. An oceanic carbon sink is called“blue carbon” that CO2in the atmosphere is absorbed by marine organisms and marine activities (Cai ZN et al., 2021;Lei XJ, 2020). Photosynthesis is the main approach to carbon sequestration. According to China’s statistics during 2010-2016, 45% of the total anthropogenic CO2emissions were sequestrated in carbon sink and the annual absorption of CO2was 3.8×109t-4.4×109t. It is expected that by 2060 China′s carbon sink will reach 6×109t of CO2(Wang J et al.,2020; Wang J et al., 2021). Studies showed that from 1949 to 2018, carbon storage from forest resources decreased at first and then gradually increased. The lowest carbon storage was during 1977 and 1981, afterward increasing on a yearly basis.The rapid growth of carbon sink was recorded since 1989,with an average annual increase of 6.05×108t CO2(Zhang YX et al., 2021). It is anticipated that by 2030 China’s forest coverage rate will increase to 25% from 23% in 2018, and forest growing stock will increase from 17.6×109m3in 2018 to 21×109m3. Additional 7.3×109t of CO2will be absorbed and stored. However, China’s oceanic carbon storage is only around 306×106t-342×106t CO2per year (Fan ZL, 2021; Jiao NZ, 2021). By 2030, China’s annual carbon sequestration will exceed 50% of contemporary anthropogenic CO2emissions,and 6×109t CO2will be stored by 2060.

The seminar on the goal and path for enhancing ecological carbon sink was held in Beijing in the context of carbon neutrality. The seminar pointed out guidelines to increase carbon sink are rules and regulations, protecting and repairing, and ecosystem quality. China will gradually complete the legal and institutional system by publishing plans, policies, and technologies. Nation-wide major projects regarding ecological protection and restoration will be carried out for the next 15 years. The principle of “sequestration,increase, expansion” was proposed to strengthen planning and regulate application. Sequestration is the protection of existing carbon storage, and specific measures are: Protecting natural ecological space and avoiding deforestation,unreasonable land use, and land destruction; protecting the authenticity, integrity, biodiversity, and carbon sink function of the ecosystem; strictly protecting and rationally utilizing forest, grassland, wetland, and other resources, and scientifically managing forest logging; lowering fire and insect pests risk to destroy forest and grassland to reduce related carbon emissions. An increase is the improvement of forest and grassland. To increase, it must follow these approaches: Launching promotion projects to improve the quality of forests, compiling scientific forest management plans, and regulating forest management activities; optimizing and adjusting the structure of tree species and stand age,planting according to local conditions, and increasing the proportion of trees with efficient carbon sequestration rate,and extending the circulation period; reinforcing the tending of young and middle-aged forests and the restoration of degraded forests, advancing the planting transformation, and continuously improving quality, carbon sequestration efficiency, and carbon storage of forests. Expansion means further expanding forest and territory greening areas and measures include: Coordinating the integrated treatment of mountain, river, forest, cropland, lake, grassland, and sand,and promoting afforestation and closing hillsides to facilitate afforestation; strengthening the treatment and restoration of degraded land, further implementing major ecological projects such as returning farmland to forests, and deeply advancing large-scale territory greening; promoting nation-wide voluntary tree planting, developing forest city and countryside landscaping, and increasing green growth and carbon sink through various resources.

4.3. Key technology

The “double carbon” technology reveals an extensive and profound revolution for the society and economy, providing a historic opportunity for green and low-carbon related technologies.

4.3.1. CCUS/CCS centered carbon industry technical system

CCUS is an important approach for China to peak and neutralize carbon emissions since it is the only technology that can achieve low-carbon utilization of fossil energy on a large scale. Although China has the capability to apply CCUS technology in industries, challenges exist due to high costs and high energy consumption. Still, relevant policies and management mechanisms need to be improved. In the future,China will develop new generation CCUS technology and accelerate the research and integrated demonstration on new generation CCUS technology. The first is to increase investment in technology research and development. Key technologies will be studied during the process of carbon capture, separation, transportation, utilization, storage, and monitoring, and large-scale full-chain integrated demonstration projects will be carried out. Secondly, CCUS technology will be applied in the commercial industry. The years 2030 to 2035 are the best period for power plant transformation through CCUS, and benefits from emission reduction will be maximized, and is the best transformation window to complete the intergenerational replacement technology, so as to avoid technology lock-in should technology change during this period before it’s finished.Third, incentive policies and standard systems shall be formed to support CCUS.

CO2has dual properties of organic conversion and greenhouse effect in the ecosystem, categorized into “grey carbon” that can be used or fixed by human beings and “black carbon” that cannot be used or fixed (Zou CN et al., 2021). In the earth’s carbon cycle, CO2mainly comes from energy consumption, agricultural and forestry land, land use, and waste emissions. “Grey carbon ” can be utilized through technologies, such as ecological sequestration, CO2-produced chemicals, artificial green conversion of CO2, and geological oil displacement, and lastly atmospheric CO2concentration can be effectively reduced. To achieve carbon neutrality,CCUS/CCS-centered technical system (Fig. 18) in the carbon industry is a revolutionary technology to completely remove“black carbon”. The technical system covers the operation of carbon capture, carbon transportation, carbon oil displacement, carbon storage, carbon production, and carbon finance (Table 5, Table 6; Zou CN et al., 2021).

Fig. 18. Structure sketch of carbon industrial system with the core of CCDUS/CCS (after Zou CN et al., 2021).

Table 6. Description of energy, product, and technology related to carbon neutrality.

Therefore, the carbon industry is low-cost and highly efficient and will be one of the keys and emerging industries for the world to achieve carbon neutrality. In the future,CCUS/CCS will store carbon in depleted oil fields, gas fields,and paddy fields with great underground storage space. In addition, policies and economic systems, like the carbon tax,carbon trading, coupling carbon emission right trading, and financial subsidies shall be established to effectively reduce CO2emissions.

4.3.2. Green hydrogen centered technical system of the hydrogen industry

Hydrogen is a secondary energy source, green energy,easily accessible, and will be leading the future energy system to renewable energy. Hydrogen energy is mostly used in the fuel cell field. Currently, hydrogen production and storage technologies are still the main factors restricting the largescale industrial development of hydrogen energy.

In China’s future hydrogen development, two aspects shall be emphasized (Lei C and Li T, 2021). First, emphasis shall be applied on the development of hydrogen supply,storage, and transportation. The development of hydrogen source supply, storage, and transportation shall adhere to local conditions on sources and production methods. During the construction of hydrogen plants, profit models shall be explored to guarantee operation. Second, hydrogen energy shall be utilized in as many various fields as possible. Except for hydrogen fuel cells, hydrogen energy can have more productive effects on the carbon peak and carbon neutrality as a major secondary energy carrier. Therefore, we should take examples from developed countries such as Europe and Japan,in hydrogen energy development to discover more application plans.

Hydrogen energy is the most ideal energy carrier in the post-petroleum era. Under the goal of carbon neutrality, it is necessary to build a full-chain hydrogen industry similar to the coal industry and petroleum industry. The system core is green hydrogen and covers the operation of preparation,storage, transportation, fueling, utilization, detection, and safety. The hydrogen industry can therefore be applied in fields of transportation involving hydrogen transportation,hydrogen storage, hydrogen chemical industry, and hydrogen metallurgy. At present, hydrogen energy mostly is produced from fossil fuels and is mainly supplied in industries, such as oil refining, synthesis ammonia, methanol production, and steelmaking. However, hydrogen energy has not been widely promoted and applied in transportation, power generation, and construction. The high cost of hydrogen energy is the main reason to hinder the application in power generation,industrial and civilian fields. The cost for manufacturing green hydrogen is expected to decrease 30% by 2030, and the price may be lower than hydrogen produced by fossil fuels(IRENA, 2020). By 2050, hydrogen energy is expected to account for about 18% of the global end-energy consumption.Even so, hydrogen energy is difficult to be widely applied in electrified industries with “zero carbon emissions” and longdistance transportation (HIS M, 2020). The hydrogen industry will replace the petroleum gas industry, and the industrial core will transform from petroleum to green hydrogen. Hydrogen energy will be widely applied in major fields such as power generation, industry, architecture, and transportation (Fig. 19).A complete hydrogen production chain will be shaped from hydrogen preparation, storage, transportation, fuel cells supply, and hydrogen fueling stations.

Fig. 19. Technical system sketch of hydrogen industry with green hydrogen as the core (after Zou CN et al., 2021).

4.4. Policy

To achieve the goal of “Double Carbon”, a sophisticated,scientific, and rational policy supporting system shall be constructed. The Chinese government intensively published CO2reduction policies in 2020. Constraints from these issued policies deeply affect the energy consumption structure and intensity adjustment procedure in China.

To achieve carbon neutrality, laws and regulation for the carbon market shall be stipulated. National administration or leader group targeting carbon neutrality will be established to overall cooperative exploration and utilization of green and low-carbon energy. A finance and tax support system shall be established to support the transition to low carbon for associated enterprises and main producing areas. The carbon trading market has two functions; those being incentive and constraint. China will establish pilot carbon emission trading markets and financial institutions are encouraged to participate. To fully develop carbon markets, international carbon pricing centers will be constructed as trading categories that will further enlarge the market (Peng Y and Zhao BZN, 2021).

5. Conclusions

(i) China will formulate vigorous policies and measures to reach the CO2peak by 2030, and carbon neutrality by 2060. A 30-year timeline is left for China to transform its economic structure, innovate technology, and invest capital, with which high requirements are expected. Brand new thinking and the strategic pattern will be applied to achieve the carbon peak and carbon neutrality. Top-line design and scientific longterm planning of the system shall be integrated to organic combine short-mid-long-term objectives and identify the most optimized transformation pathway.

(ii) Our different approaches will be available for China to achieve carbon neutrality. (1) For controlling CO2emissions:energy transition pathway, energy reduction and saving pathway; (2) increasing carbon sink: carbon capture and storage pathway, ecological treatment, and land greening pathway; (3) developing key technology: zero-carbon utilization, integrated coals, and new energy, CCUS, storage technology, essential key technology pathway to achieve carbon peak and carbon neutrality; (4) formulating policy:legal guarantees enacted by the government to promote carbon trading market, carbon emission standard targeting enterprises, targeting publicity and education targeting the individual and society.

(iii) China needs fully reforming in the economy, energy consumption, and infrastructure. The idea of energy-saving and efficiency improvement leads to the development of a carbon circular economy. In the fossil fuel energy stage,energy structure cannot be transformed and optimized without the promotion and development of clean energy. The utilization of renewable energy and zero-carbon technology can largely reduce energy dependency on fossil fuels.Renewable energy includes wind, solar, oceanic, and geothermal energy, and zero-carbon technologies are hydrogen, new material energy storage, intelligent energy,nuclear energy, and controlled nuclear fusion. The ecological carbon storage capability is strengthened through territory planning and application regulation, effectively expanding the carbon storage of forests, grasslands, wetlands, the oceans,soil, and permafrost.

(iv) Both opportunities and challenges exist in the achievement of carbon peak and carbon achievement for China, with a promising prospect. China′s economy is growing rapidly but also facing the internal pressure of energy consumption and carbon emissions reduction. Meanwhile,China has become the world’s second-largest economic entity and has the capital and capability to achieve carbon peak and carbon neutrality. On the way to carbon peak and carbon neutrality, China will largely promote the development of a carbon circular economy and green economy with high speed and quality. The energy consumption and structure will be transformed by accelerating the utilization of fossil fuels.Green low-carbon technology will be integrated and innovated to propel carbon neutrality. The goals of carbon peak and carbon neutrality bring new opportunities and challenges to economic and social development. In the future,theories and key technologies are still demand reinforced adaptation to climate change and finally support the carbon peak and carbon neutrality.

CRediT authorship contribution statement

Yao Wang and Chi-hui Guo conceived of the presented idea. Chi-hui Guo developed the theory and wrote the original draft. Xi-jie Chen, Li-qiong Jia, Xiao-na Guo, Rui-shan Chen and Mao-sheng Zhang reviewed and edited the manuscript.Hao-dong Wang helped improve the figures and tables in the manuscript. All authors discussed the results and contributed to the final manuscript.

Declaration of competing interest

The authors declare no conflicts of interest.

Acknowledgment

This study was supported by the project of China Geological Survey (DD20211413, Comprehensive Evaluation of Ecological Protection and Utilization of Natural Resources).