“In the aspect of managing air pollution, research group of Tsinghua University have never been absent from any important national event.” On May 7, HE Kebin, the academician of Chinese Academy of Engineering, and professor of School of Environment, Tsinghua University, said while exclusively interviewed by media including Science Daily, in key battles including air quality assurance for Beijing Olympic, plan of controlling air pollution, and the battle to save the blue sky, the platform developed independently by Tsinghua University which took more than 20 years played a great role in them. It is continuing to contribute to the scientific assessments and decision support of collaborative governance of reduction of pollution and carbon emissions in the context of peak carbon dioxide emissions and carbon neutrality.

Recently,National Science Reviewpublished the research results,Pathways of China’sPM_2.5Air Quality 2015-2060 in the Context of Carbon Neutrality,accomplished by Tsinghua University and its collaborating teams jointly, and supported by the autonomous platform. It quantitively revealed the continuous improving way of air quality from 2015 to 2060 in China and the key areas under the goal of peak carbon dioxide emissions and carbon neutrality for the first time.

Picture Source: Visual China Group

How many steps does it take to return carbon emissions to zero? Autonomous platform can work it out.

“The autonomous platform can dynamically simulate productive activities and alteration in discharge of all walks of life in China from past to now,” ZHANG Qiang, one of the main authors of the paper, the Professor of the Department of Earth System Science, Tsinghua University, introduced that, in China Carbon Neuralization and Clean Air Collaborative Scientific Evaluation and Decision Support Platform (CNCAP), emissions of every industry will have a panoramic reveal.

These emission paths are dynamic, and can be interpreted as an “interactive drama”. When exerting various interference (such as industry development, technology renovation, governance measures, etc.), “tendency” of emission varies. Further, emission paths of distinct industries meet, and together they affect atmospheric environment change in China.

The platform can estimate changes in carbon emissions andair pollutant emissions in 2030, so far as to that in 2060, and eventually present the change in air quality.

“The platform consists of multiple independently developed models including Multi-resolution Emission Inventory for China (MEIC), Dynamic Projection model for Emissions in China (DPEC), and Tracking Air Pollution in China (TAP), which contains a lot of data of industries, techniques, spatial locations, energy consumption, and emissions,” explained ZHANG Qiang. The platform has over a thousand types of carbon emissions and air pollutant emissions sources, which are from industrial, electrical power, traffic, and civil fields, and every subdivided industry includes existing techniques, alternative techniques, and techniques under development.

Undoubtedly, to be able to “twin” China’s emissions situation in such a vivid way, and to collect and operate tons of data based on various algorithm and models requires incalculable computing power.

“Sunway TaihuLight Supercomputer provides operating services for the platform,” said ZHANG Qiang. National Supercomputer Wuxi Center is operated and maintained by Tsinghua University, providing powerful computing power and fundamental services for establishment of algorithm models and operation of autonomous platform.

“Digital Twin” of Emissions, different historical stages have different emphases

Peak Carbon dioxide emissions and carbon neutrality is undoubtedly an epic practical masterpiece of human response to climate change for some time to come.

In the “digital twin” simulation of this epic, the final goal is very clear: China will work hard for the carbon dioxide emission to peak before 2030, and strive for realizing carbon neutrality before 2060.

How to achieve the goal of collaborative pollution and carbon reduction? Base on real world simulation, CNCAP platform helps the policymakers to focus on the key points, and makes circumstance prediction to provide policy suggestions.

Research finds that, before 2030, increasing the proportion of renewable energy, promoting the output of high energy consuming products such as steel and cement to peak as soon as possible, promoting pollution control in non-electric industry, diesel engine and other key industries continuously, can achieve the goal of peak carbon dioxide emissions and enable the annual concentration ofPM_2.5 to reach the standard in most of the country.

“In the past few years, emission reduction is mainly achieved by end-of-pipe treatment. By installing end-of-pipe treatment measures and strengthening supervision at heat-engine plant, cement plant and steelworks, we have achieved remarkable results, such as realizing ultra-low-emission in electric power industry,” said HE Kebin.

However, with the progress of treatment, boundaries of end-of-pipe treatment emerge slowly. New plan is needed for the future.

“If the pollution treatments relied on the ground forces in the past, conducting the carbon reduction of energy structure now corresponds to air force and artillery,” HE Kebin points out that, changing the energy structure will become the main driving force of emission reduction in the future.

For instance, according to simulating research, Beijing-Tianjin-Hebei region is still going to be a region with relatively high carbon emissions in the future. “Since steel and cement are advantageous industries of Hebei, they are the most difficult to reduce carbon due to the constraints of existing technologies. However, developed countries have already implemented hydrogen energy steel production commercial demonstration projects, which reminds us to actively develop clean energy technology reserves for steelmaking in terms of technology innovation," said ZHANG Qiang.

"Transformation of energy structure requires leading of technology," HE Kebin said that the drastic fall in the cost of photovoltaic power generation in recent years has given a good example (from $100/kWh in 1990 to less than 2 cents/kWh in 2020).

According to the forecasts, China will mainly complete the transformation to low-carbon energy by 2060. Renewable energy will account for more than 70% of electrical power generation, the proportion of end coal consumption in the industrial section will be less than 15%, the proportion of new energy vehicles will reach more than 60%, and the civil section energy is comprehensively cleaned. By then, the average annualPM_2.5exposure level of national population will reach about 8 micrograms/cubic meter, and the air pollution problem will be fundamentally solved.

The underappreciated fundamental research gives confidence of “autonomy”

While looking forward to emissions to "return to zero", some may ask: is the prediction for the future accurate enough?

"On this platform, the emissions of a steel plant will be meticulously depicted," HE Kebin cited an instance, "its emissions of different technologies such as ironmaking, steelmaking, and coking are different, and the system will be embodied by being divided into various nodes and technologies."

With the development of the platform, the accuracy of model simulation has improved from low to high, and the amount of data has increased from small to large, from model development to software development to super-computing power, CNCAP platform reproduces the change in China’s air quality realistically in the digital world with the advantage of independent innovation.

"From the 1990s to the present, more than 20 years, we have been doing the same thing, that is to establish links between China's production and discharge of pollutants," said HE Kebin. This is arguably the most complex system in the world. It not only spans over large regions and includes many types of pollutants, but also covers the most backward to the most advanced technologies.

The accumulation of data in the past 30 years is all presented in this decision support platform. Not only carbon emissions, but also how much particulate matter emissions, how much sulfur dioxide emissions, how much nitrogen oxide emissions, and how much volatile organic compounds is discharged... how the air quality will change. This platform can not only present rough answers to these questions, but also present gridding and high-precision "blueprint” that is distributed to space and time.

"In the situation of global climate change andthe context of great strategy of peak carbon dioxide emissions and carbon neutrality, we will further develop real-time dynamic simulation technology for emissions, structure a full composition emission inventory of all kinds of toxic and harmful substances, explore the interaction mechanism between climate change and air pollution, optimize the collaborative approach for carbon neutrality and air quality improvement, and continuously improve the platform's decision support capability of collaborative response to pollution and carbon reduction," said HE Kebin.

According to the reports, the research and development of this platform has received financial support from multiple national scientific research projects, including 863, 973, key research and development plans, special research projects, and National Natural Science Foundation of China. The results produced by the platform have supported works including air quality simulation and future scenario evolution analysis of more than 300 academic institutions around the world. China's air quality forecasting system also uses the emission data provided by the platform.

ZHANG Jiaxing, Reporter of Science Daily

Source: Science Daily