Carbon Emissions In Power Sector Research Articles

Unlocking Power: Impact of Physical and Mechanical Properties of Biomass Wood Pellets on Energy Release and Carbon Emissions in Power Sector

Abstract This study investigates the physical and mechanical properties of 12 biomass wood pellet samples utilised in a power generation, focusing on their implications for energy release and carbon emissions during combustion. Through comprehensive analysis involving bulk density measurements, compression tests, moisture analysis, calorimetry and controlled burning experiments, significant correlations among key properties are identified. Pellets with densities above 1100 kg/m3 demonstrate superior mechanical durability and strength, achieving maximum strengths of 0.6 to 0.8 kN with durability exceeding 99.4%. Optimal moisture content, typically between 6 and 7% is crucial for maximising density, bulk density, mechanical durability and fracture resistance, ensuring robust pellet structure and performance. The research underscores the impact of pellet dimensions, highlighting those longer lengths, > 12 mm enhance durability, while larger diameters > 8 mm exhibit reduced durability. Elemental analysis focusing on calcium, silicon and potassium plays a critical role in predicting and managing combustion system fouling, potentially reducing operational costs. Moreover, the study emphasises the significant influence of oxygen levels during combustion on CO2 emissions, achieving optimal results with moisture content in the 7–8% range for maximum higher heating value (HHV). The moisture content in the 14–15% range represents the lowest CO2 emission. The findings underscore the intricacy of the system and the interplay of parameters with one another. In accordance with the priority of each application, the selection of parameters warrants careful consideration. Graphical Abstract

CO2 emissions of constructing China's power grid towards carbon-neutral target: Based on top-down and bottom-up integrated model.

Power sector is the largest industrial emitter in China, and renewable energy development would contribute to the large-scale construction of power grid. Mitigating carbon emissions of power gird construction is extremely important. So, the objective of this study is to understand embodied carbon emissions of power grid construction under carbon neutrality target, and then put forward to policy implications of carbon mitigation. This study, based on top-down and bottom-up integrated assessment models (IAMs), investigates carbon emissions of power grid construction towards 2060, through identifying the key driving factors and forecasting their embodied emissions in line with China's carbon neutrality target. Our results show that, the increase of Gross Domestic Product (GDP) dominates the increase in embodied carbon emissions of power grid construction, while energy efficiency and energy structure improvement contribute to the decrease. Large scale renewable energy development promotes the power grid construction. In 2060, total embodied carbon emissions would increase to 1105.7 Million tons (Mt) under the carbon neutrality target. However, the cost and key carbon-neutral technologies should be re-considered to ensure the sustainable electricity supply. The results could provide data reference and decision-making of designing power construction and mitigating carbon emissions of power sector in future.

Drivers of renewable energy penetration and its role in power sector's deep decarbonization towards carbon peak

The power sector is a linchpin of global carbon mitigation goal, and renewables are increasingly the preferred source of new electricity generation globally. It is necessary to uncover the driving mechanism of renewable energy penetration and its impact on deep decarbonization of the power sector. To this end, this research utilizes the production-theoretical decomposition analysis to attribute the change in renewable electricity generation to nine drivers. Then, a system dynamics model is established to track the trajectory of carbon emissions in the power sector under multiple scenario settings of renewable energy penetration. Additionally, cross-country heterogeneity analysis is conducted between China, the USA, the UK, and Germany. The results indicate that: (1) The electricity consumption scale plays a decisive role in driving China's renewable electricity generation during 1995–2018, while electricity productivity and output productivity are the major negative contributors. (2) In the UK, the USA, and Germany, electricity productivity and output productivity act as the main promoters of renewable electricity generation. (3) The decline in China's two productivity effects is primarily attributed to the drop of technical efficiency. However, technology progress in these developed countries contributes to increasing the two productivity indexes. (4) The IRENA roadmap scenario (40%) is not enough to peak carbon emissions in China's power sector before 2030, while 46.3% of renewables in electricity generation is sufficient to achieve this goal. This research provides an insightful roadmap for facilitating renewable energy transition and decarbonizing the power sector.

Decomposition and decoupling research of Chinese power sector carbon emissions through the consumption accounting principle.

The Logarithmic Mean Divisia Index (LMDI) model is applied to study Chinese national and regional power sector carbon emission changes through consumption side from 2003 to 2017, and regional power sector carbon emissions are estimated through the production and consumption accounting principle. The two-factor ANOVA and one-factor ANOVA are used to compare the differences of regional power sector carbon emissions through the two principles. In addition, the Tapio decoupling analysis model is used to investigate the decoupling state between carbon emissions of power sector and the corresponding driving forces through the consumption side. There are several results: (1) Through the two different principles, regional power sector carbon emissions are statistically significant, yet national power sector carbon emissions are not statistically significant; (2) the main factors contributing to the power sector carbon emission growth are economic scale effect and income level effect, and the main restraining factors are electricity consumption carbon intensity effect and production sector electricity intensity effect; (3) the highest contribution effect to the decoupling indexes between various influencing factors and power sector carbon emissions was scale effect, and technical effect had the second largest contribution value; (4) in 2003-2017, economic scale effect was the first significant factor causing the difference of regional power sector carbon emissions, followed by production sector electricity intensity effect and electricity consumption carbon intensity through the regional decomposition analysis. Finally, this paper gives some targeted suggestions for the low-carbon development of the power sector through national and regional perspectives.

Study on the biomass-based integrated gasification combined cycle with negative CO2 emissions under different temperatures and pressures

To reduce the carbon emissions in power sector, a biomass-based integrated gasification combined cycle (BIGCC) with oxy-fuel combustion is proposed. The syngas generated from biomass gasification is burned under oxy-fuel atmosphere for power generation, and CO2 in the flue gas is captured by merely cooling. Thus, the negative CO2 emissions are realized considering the carbon neutral character of biomass. The effects of gasification temperature and pressure on syngas composition and system performance are investigated. The results show that rising pressure and temperature lead to lower H2 and CO production, while CO2 and CH4 generation are enhanced with higher pressure and lower temperature. The system efficiency increases with the pressure rise, while it fluctuates with the temperature variation. The optimum temperature and pressure of gasification is 1000 °C and 3.5 MPa. The corresponding energy and exergy efficiency is 35.41% and 31.21%. The thermodynamic analysis is carried out for each subsystem. The energy loss and exergy destruction is 76.2% and 55.4% for gasifier and 21.8% and 31.3% for HRSG. Considering the unavoidable energy and exergy consumption in gasification, the system optimization can be concentrated on HRSG. The efficient power generation and significant carbon emissions reduction are achieved in the proposed system.

Regional power system modeling for evaluating renewable energy development and CO2 emissions reduction in China

This study demonstrates how a regional power system modeling tool could be applied to evaluate renewable energy development and emissions reduction with technology change and market reform. We introduce a capacity expansion and operation model with provincial details for China's power system – the Renewable Electricity Planning and Operation (REPO) Model. We compare the spatial and temporal variation of renewable energy development under three alternative scenarios that depict three potentially important technology and reform directions – flexible district heating technology, ultra-high voltage transmission technology and complete spot market to the reference scenario. Under the reference scenario, the share of non-hydro renewable energy in China's power sector will reach 11.3% and carbon emissions of the power sector will increase to 5.1 billion metric tons in 2050. With assumptions made in the flexible district heating technology, ultra-high voltage transmission technology and complete spot market scenario, the share of non-hydro renewable energy in the power sector could increase to 14.3%, 11.5%, and 23.7%, and carbon emissions of power sector will change by −0.3, +0.0, and −1.0 billion metric tons in 2050, respectively. Similar analyses could be extended to other developing countries that plan to deregulate and decarbonize their power systems.