China's rapid economic growth over the past three decades has led to massive fossil fuel consumption, resulting in significant greenhouse gas and air pollution emissions. This poses serious threats to global warming and public health. The "13th Five-Year Plan" established a national strategy for a clean-energy society and ecological preservation, including ambitious carbon emission reduction targets aligned with the Paris Agreement. A major source of air pollution in Northern China stems from rural residents burning raw coal for heating. While this practice offers low cost and high heat value, it releases substantial SO2, NOx, and particulate matter. To address this, a series of Electric Heating Policies (EHPs) were implemented since 2015, aiming to replace raw coal with electric heating. While improving air quality, this transition caused a sharp increase in electricity demand, potentially increasing carbon emissions from power generation. Existing literature addresses the environmental impacts of China's residential heating, but few studies quantify the greenhouse gas impacts of EHP or explore its conflict with carbon mitigation goals. This study aims to quantify the contribution of China's EHP to national carbon emissions using a theoretical model encompassing power generation and rural residential heating sectors. It further analyzes key factors influencing policy implementation and provides policy suggestions for low-carbon electric heating.

A considerable body of research exists on the environmental impacts of China's residential heating sector. Studies have estimated carbon and pollutant emissions, analyzed policy implications for emission control, and investigated the effects on life expectancy and public health. However, there is a notable gap in quantifying the greenhouse gas impact specifically from electric heating and the inherent tension between China’s EHP and its overarching carbon mitigation goals. This study addresses this gap by providing a quantitative assessment of the EHP’s carbon footprint.

The study employs a theoretical model to quantify CO2 emissions from both power generation and rural residential heating. Data on rural resident population, housing areas, household heating coal consumption, household electric heating load, and rooftop solar power were collected from various sources, including the Sixth National Census, the "Report on Chinese Residential Energy Consumption," and the World Meteorological Organization's weather dataset. EnergyPlus, a building energy consumption simulation software, was used to simulate household heating coal consumption and electric heating load, considering outdoor air temperature, indoor comfort temperature, and housing area. Data on thermal generator parameters, renewable power, and electric power system load were collected from power grid companies in four Northern Chinese provinces: Hebei (HB), Henan (HN), Shandong (SD), and Shanxi (SX). A day-ahead unit commitment model was formulated to quantify thermal coal consumption, minimizing generation costs and considering constraints such as power balance, spinning reserve requirements, and generator operational limits. The model incorporates renewable power and net electric heating load data. The study expands its findings from the four provinces to the entire Northern China region, considering factors such as per capita heating coal consumption and per capita electric heating load. The total heating coal and thermal coal consumption were estimated for Northern China. The emission factors for raw coal and thermal coal were calculated based on their heating values and net carbon contents. The final CO2 emission calculation incorporated emissions from both residential heating coal and thermal coal consumption. A cost analysis for various electric heating pathways, including electric heaters (EHs), heat pumps (HPs), and photovoltaic-powered electric heating (PVEH), was also conducted.

The study's key findings show that the implementation of EHP significantly increases provincial and national carbon emissions. In 2015, the incremental carbon emission in Northern China was estimated to be 135.60 megatons in the base case (50% policy implementation rate), ranging from 101.69 to 162.89 megatons considering uncertainties in policy implementation and electric heating mix. This represents a substantial increase compared to the emissions from using raw coal. In 2020, this is projected to reach 168.80 megatons, ranging from 130.03 to 197.87 megatons. However, by 2030, due to urbanization, the growth slows down with the carbon emission increase dropping to 119.19–177.47 megatons. The provincial carbon emissions vary based on climate conditions (ambient air temperature), rural resident population using electric heating, and the thermal coal consumption rate of marginal power generation units. Shandong province displayed the highest daily average electric heating load (54.35 kWh), while Henan had the lowest (36.71 kWh). The thermal coal consumption rate directly impacts carbon emission intensity; Shanxi, a large power exporter, had the highest intensity (635.71 kg/MWh). The study explores low-carbon pathways to offset these increases. Integrating inter-provincial renewable energy effectively reduces carbon emissions, although the marginal reduction decreases with higher renewable energy penetration. Installing distributed photovoltaic (PV) systems also significantly reduces emissions, but the reduction rate declines with increasing PV capacity. Replacing electric heaters (EHs) with heat pumps (HPs) offers another viable path, with estimates suggesting that a 60-90% HP adoption rate is needed to completely offset EHP-induced carbon emissions. The cost analysis reveals that while electric heaters currently are cost-effective compared to heat pumps, the integration of solar power with appropriate subsidies can make it competitive. However, reductions in solar energy subsidies will increase the cost making it less competitive.

The findings highlight the unintended consequence of China's EHP, demonstrating a significant increase in carbon emissions despite achieving improved air quality. This underscores the importance of considering the broader environmental impact when designing and implementing policies. The observed trade-off between air quality improvement and increased carbon emissions necessitates a holistic approach. The model's conservative estimates, which do not fully account for transmission and distribution network losses, suggest that the actual carbon impact may be even larger. The exploration of low-carbon pathways using renewable energy integration and efficient heating technologies presents viable solutions to mitigate the EHP's carbon footprint. The effectiveness of these solutions, however, is dependent on factors such as the availability of renewable energy resources, the level of renewable energy curtailment, and the cost-effectiveness of heat pumps. The cost analysis demonstrates that policy incentives, such as subsidies for solar power and heat pumps, are crucial in promoting the adoption of these low-carbon technologies among rural residents.

This study demonstrates a significant increase in carbon emissions resulting from China's EHP, despite its positive impact on air quality. The analysis underscores the need for a comprehensive approach to policy-making, anticipating and addressing potential trade-offs. The suggested low-carbon pathways, focusing on renewable energy integration and efficient heating technology, offer effective mitigation strategies. Future research should investigate the impact of network congestion on renewable energy curtailment, explore innovative policy designs to balance air quality and carbon emission targets, and further refine cost-benefit analyses for different low-carbon technologies.

The study's limitations stem primarily from data availability. Power transmission and distribution network losses were not incorporated into the electricity dispatch model due to limited data, potentially underestimating future renewable energy curtailment. The model's estimation of total heating coal and thermal coal consumption in Northern China relies on extrapolations from four provinces, introducing uncertainties. Future research should address these data limitations for a more comprehensive assessment.