Quantitative Assessment Of Carbon Reduction Responsibility Of Heterogeneous Energy Source In Power System

Global warming caused by excessive emissions of greenhouse gases due to human activities has posed a serious challenge to human development,and China,as the largest emitter of carbon,is facing enormous pressure and responsibility to reduce emissions.As a major emitter of CO2 emissions in China,the power system needs to take up an important responsibility for carbon reduction.Renewable Energy Sources has huge potential to reduce emissions due to its zero-carbon nature,and is an important technology option for achieving"carbon peaking and carbon neutrality" and decarbonisation in the power sector.However,with the increasing penetration of renewable energy sources such as photovoltaic and wind power in the power system,the intermittent,uncertain and fluctuating nature of their power generation not only poses a huge challenge to the safe and stable operation of the power system,but also has a negative impact on the overall operational efficiency of the power system and carbon emissions of thermal power units.From the perspective of the power system as a whole,renewable energy does not have independence,i.e.it does not have the ability to follow system load changes independently.In order to adapt to the net load changes caused by renewables,thermal power with controllability will change from a base load power source to a regulating power source,which will lead to a reduction in the operating efficiency of thermal power units,an increase in the intensity of unit carbon emissions and additional carbon emissions.In the context of low-carbon electricity,it is obviously unfair to let the thermal power system bear the responsibility of additional carbon emissions.To the above issues,this paper focuses on the mechanism of additional carbon emissions caused by renewable energy in the power system,with the theme of quantitative assessment of carbon emission reduction responsibilities of heterogeneous energy sources in the power system.The main work and research results of this paper are summarised as follows:(1)The evaluation method for the additional carbon emission of renewable energy has been proposed.The mechanism of additional carbon emissions from renewable energy sources is revealed.Firstly,the basic operating scenario and alternative scenario of the power system with and without renewable energy grid connection are constructed,taking into account the uncertainty of renewable energy output.Based on the robust optimization unit combination model of the power system,short-term production simulation is conducted,and the difference in system carbon dioxide emissions between the two scenarios is calculated through the model as the actual carbon reduction of renewable energy power generation.Secondly,based on the marginal emission factor,evaluate the equivalent emission reduction of renewable energy generation substitution under ideal conditions,and compare it with the actual carbon reduction of renewable energy to extract additional carbon emissions.Finally,based on the IEEE RTS-96 testing system,production simulation was conducted to reveal the mechanism of additional carbon emissions from renewable energy,providing basis and data support for the allocation of responsibility for additional carbon emissions between renewable energy and thermal power unit.(2)The mechanism for sharing the responsibility of carbon emission reduction among heterogeneous energy players is proposed.Based on the mechanism of additional carbon emission,a model is constructed based on cooperative game theory to share the responsibility for additional carbon emissions between thermal and renewable energy source.Based on the Shapley value sharing method,the responsibility is shared according to the marginal contribution of the energy players to the additional carbon emission of the coalition.Further,the Shapley value method is improved by introducing an integrated correction factor that takes into account the load-following characteristics and the available generation capacity,which corrects the homogenisation of the Shapley value solution for the individual variability of different energy players,thus stimulating the renewable energy sources to optimise their output curves and improve the load-following characteristics.Finally,the Shapley value estimation method is used to share the additional carbon emission responsibility among multiple energy sources,taking into account the "combinatorial explosion" problem arising from the application of the Shapley value method to large power system.The fairness and effectiveness of the proposed apportionment method is verified based on simulation.(3)The low-carbon optimal dispatch strategy that takes into account the carbon reduction responsibilities of heterogeneous energy sources.In order to ensure fairness and incentive,the additional carbon emission responsibility of renewable energy is taken into account in the low-carbon optimal dispatch strategy.The carbon trading mechanism is combined with the additional carbon emission responsibility of renewable energy,and the offsetting mechanism for renewable energy is proposed based on the additional carbon emission responsibility of renewable energy and the offsetting of excess emission credits of thermal power units with efficiency losses.In addition,as the energy mix is dominated by thermal power,carbon capture and storage units have become an important transitional source of power for decarbonisation and power supply retention after large-scale renewable energy is connected to the grid.A robust low-carbon optimal dispatch model is developed to take into account the additional carbon emission responsibility and carbon capture technology,and a nested Benders decomposition method is used to solve the model.The fairness and effectiveness of the proposed low-carbon optimal dispatch model are verified through case studies,which provide a reference for the development of low-carbon power system.