• Energy Research

Climate change present a range of equity issues for human being, but operating the equity principle within emission allocation scheme to various parties has raised multiple challenges. Although more than 40 schemes have been suggested in the literatures, there is little consistency in the way that baselines, scope, coverage and other key parameters have been compared or discussed. In this paper, we reviewed 41 schemes used in the literature so far and compared the cumulative allowances of main countries under various schemes in a consistent framework. Two cases are considered, i.e. only energy and industry related CO2 and all Kyoto GHGs. Besides the allowances, carbon Gini coefficient in the global perspective and the reduction tradeoffs between country groups are further quantitatively discussed. It is demon- strated that the full ranges of countries' allowances are quite large resulting from different equity consid- erations and implement methods behind different effort-sharing schemes. However, absolute mitigations are always required in developed countries in order to realize the 2 C target, regardless of schemes.

Abstract China is facing a huge challenge in achieving its carbon neutrality goal by 2060 given that it is currently one of the world’s largest greenhouse gas (GHG) emitters and has set a very short timeline for going from peak emissions to carbon neutrality. Natural climate solutions (NCS) that protect, manage, and restore ecosystems have shown substantial potential for increasing carbon sinks or reducing GHG emissions to offset fossil fuel CO2 emissions. This study quantified the mitigation potential of 18 NCS pathways in China at 0.67–1.65 Gigatonne of CO2 equivalent (Gt CO2e) yr−1 averaged from 2020 to 2060, which is even larger than the size of the current national terrestrial carbon sink. Compared with a previous global estimate, our results show a lower mitigation potential in forest ecosystems but a much greater potential for cropland ecosystems in China. From 2020 to 2060, all 18 pathways combined can provide cost-effective mitigation compared to the global social cost of CO2 emission and carbon prices, and 98.6% and 83.3% mitigation potential are cost-effective, respectively. This study further showed that immediate action provides the greatest mitigation. Our estimates highlight the important role of NCS in achieving the national carbon neutrality goal because of their large mitigation potential and cost-effectiveness.

In order to achieve the Paris Agreement goals of keeping the temperature rise well below 2 °C or even 1.5 °C, all countries would need to make fair and ambitious contributions to reducing emissions. A vast majority of countries have adopted reduction targets by 2030 in their Nationally Determined Contributions (NDCs). There are many alternative ways to analyze the fairness of national mitigation contributions. This article uses a model framework based on six equity principles of effort-sharing, to allocate countries’ reduction targets under global emissions scenarios consistent with meeting the Paris climate goals. It further compares these allocations with the NDCs. The analysis shows that most countries need to adopt more ambitious reduction targets by 2030 to meet 2 °C, and even more for 1.5 °C. In the context of 2 °C, the NDCs of the United States of America and the European Union lack ambition with respect to the approaches that emphasize responsibility; China's NDC projection falls short of satisfying any approach in 2030. In the context of 1.5 °C, only India, by implementing its most ambitious efforts by 2030, could be in line with most equity principles. For most countries, the NDCs would use most of their allowed emissions space for the entire 21 st century by 2030, posing a major challenge to transform to a pathway consistent with their fair contributions in the long-term.

Nationally Determined Contributions (NDCs) are a core component for post-2020 global climate agreements to achieve the 2 °C goal in addressing climate change. In the NDC, China has declared to lower carbon intensity by 60–65% from the 2005 level by 2030 and achieve the peak of CO2 emissions around 2030. In the context of the 2 °C goal, this study assesses China’s CO2 mitigation targets in the NDC using fair ranges of emissions allowances as calculated from an effort-sharing framework based on six equity principles (and cost-effectiveness). Results show that understanding the fairness of China’s NDC would rely heavily on selected equity principles. If the 65% target is implemented, China’s NDC would position within full ranges of emissions allowances and align with responsibility–capacity–need based on comparisons in 2030, and with responsibility–capacity–need and equal cumulative per capita emissions based on comparisons during 2011–2030. Implications of the NDC on China’s long-term CO2 mitigation targets beyond 2030 are also explored, which indicate that China’s energy system would need to realize carbon neutrality by 2070s at the latest in the scenarios in this study.

Abstract A method, based on spatial analysis of the different criteria to be taken into consideration for building scenarios of CO 2 capture and storage (CCS), has been developed and applied to real case studies in the Hebei province. Totally 88 point sources (42 from power sector, 9 from iron and steel, 18 from cement, 16 from ammonia, and 3 from oil refinery) are estimated and their total emission amounts to 231.7 MtCO 2 /year with power, iron and steel, cement, ammonia and oil refinery sharing 59.13%, 25.03%, 11.44%, 3.5%, and 0.91%, respectively. Storage opportunities can be found in Hebei province, characterised by a strong tectonic subsidence during the Tertiary, with several kilometres of accumulated clastic sediments. Carbon storage potential for 25 hydrocarbon fields selected from the Huabei complex is estimated as 215 MtCO 2 with optimistic assumption that all recovered hydrocarbon could be replaced by an equivalent volume of CO 2 at reservoir conditions. Storage potential for aquifers in the Miocene Guantao formation is estimated as 747 MtCO 2 if closed aquifer assumed or 371 MtCO 2 if open aquifer and single highly permeable horizon assumed. Due to poor knowledge on deep hydrogeology and to pressure increase in aquifer, injecting very high rates requested by the major CO 2 sources (>10 MtCO 2 /year) is the main challenge, therefore piezometry and discharge must be carefully controlled. A source sink matching model using ArcGIS software is designed to find the least-cost pathway and to estimate transport route and cost accounting for the additional costs of pipeline construction due to landform and land use. Source sink matching results show that only 15–25% of the emissions estimated for the 88 sources can be sequestrated into the hydrocarbon fields and the aquifers if assuming sinks should be able to accommodate at least 15 years of the emissions of a given source.

As the world's biggest carbon dioxide (CO2) emitter and the largest developing country, China faces daunting challenges to peak its emissions before 2030 and achieve carbon neutrality within 40 years. This study fully considered the carbon-neutrality goal and the temperature rise constraints required by the Paris Agreement, by developing six long-term development scenarios, and conducting a quantitative evaluation on the carbon emissions pathways, energy transformation, technology, policy and investment demand for each scenario. This study combined both bottom-up and top-down methodologies, including simulations and analyses of energy consumption of end-use and power sectors (bottom-up), as well as scenario analysis, investment demand and technology evaluation at the macro level (top-down). This study demonstrates that achieving carbon neutrality before 2060 translates to significant efforts and overwhelming challenges for China. To comply with the target, a high rate of an average annual reduction of CO2 emissions by 9.3% from 2030 to 2050 is a necessity, which requires a huge investment demand. For example, in the 1.5 °C scenario, an investment in energy infrastructure alone equivalent to 2.6% of that year's GDP will be necessary. The technological pathway towards carbon neutrality will rely highly on both conventional emission reduction technologies and breakthrough technologies. China needs to balance a long-term development strategy of lower greenhouse gas emissions that meets both the Paris Agreement and the long-term goals for domestic economic and social development, with a phased implementation for both its five-year and long-term plans.

Abstract We analyzed the impacts of incorporating local air quality improvement and environmental co-benefits into the climate policy and mitigation technology assessment of the cement sector in China. Local air quality can benefit from reducing greenhouse gas emissions, which consequently lowers abatement costs and strengthens the cost-effectiveness of mitigation technologies. We used a simplified approach to estimate environmental damage factors due to air pollution at the sub-national level in China. The calculated economic costs of environmental damage due to PM10, NOx, and SO2 were 7,714 $/t, 1,006 $/t, and 902 $/t, respectively. These values vary among the provinces. We found that most energy-saving technologies in the cement industry will create significant co-benefits, ranging from 3 $/t CO2 to 39 $/t CO2 at the national level; however, a tradeoff for carbon capture and storage (CCS) and energy-saving technologies also resulted with increased electricity consumption. Large spatial variations of co-benefits can be gained at the sub-national level and justify the enactment of more stringent climate policies in the wealthier regions in China.

Abstract The prohibitive cost of carbon abatement has put large pressure on China’s government during its carbon mitigation process to meet the country’s target for Intended Nationally Determined Contributions (INDC). Previous studies mostly focus on the cost analysis of China’s INDC. This study fills the gap between the cost of carbon mitigation and auxiliary benefits, and attempts to answer the following key questions associated with China’s INDC: (1) How much of the mitigation cost can be offset by environmental benefits? (2) What is the break-even carbon mitigation rate? (3) Is China’s INDC carbon reduction target cost effective? In this study, carbon tax is added into China-Multi-Pollutant Abatement Planning and Long-term Benefit Evaluation (China-MAPLE). The corresponding carbon mitigation rate is calculated to construct the marginal abatement cost curves (MACCs). The environmental co-benefit from air pollutant abatement is evaluated by the health damage avoided, and the benefit is added into the revised MACCs. Several conclusions are drawn from analysis based on MACC and China-MAPLE model. First, the net cost of carbon abatement can be substantially reduced when considering environmental benefits. When mitigation rate in normal end-of-pipe control (NEPC) scenario is below 16.8%, carbon mitigation cost is fully compensated by environmental benefits. Second, if strict end-of-pipe control (EPC) measures are implemented, then environmental benefits can be sternly influenced but can continue to fully compensate the cost when mitigation rate is below 3%. Third, the carbon mitigation target of China’s INDC is achievable and cost effective under the NEPC scenario. Carbon mitigation cost is 0.08% of the GDP loss, which is compensated by the 0.14% environmental benefit of the GDP. As a result, a net benefit of 0.06% of the GDP is obtained. The cost effectiveness of China’s INDC is largely dependent on the stringency of EPC measures. However, even in the strict EPC scenario, 0.02% of the GDP loss accounting for the mitigation cost is partially offset by environmental benefits. These results strongly support the implementation of China’s serious de-carbonization effort toward its INDC and serve as a good reference for other developing countries.